IVI STEP TYPES. Contents

Transcription

1 IVI STEP TYPES Contents This document describes the set of IVI step types that TestStand provides. First, the document discusses how to use the IVI step types and how to edit IVI steps. Next, the document describes the functionality of each of the IVI step types. Overview... 3 Editing an IVI Step... 5 Expression Controls... 6 Extensions... 7 Operation Settings... 8 Validating a Configuration... 9 Using Soft Front Panels Get Information Instrument Session Manager IVI Dmm Step Configure Basic Tab Advanced Tab Temperature Tab Extensions Tab Operation Settings Tab Read and Fetch Initiate Abort Send SW Trigger Get Information Step Properties IVI Scope Step Configure Basic Tab Advanced Tab Channels Tab Trigger Tab CVI, LabVIEW, TestStand, National Instruments, and ni.com are trademarks of National Instruments Corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies A-01 Copyright 2001 National Instruments Corp. All rights reserved. March 2001

2 Extensions Tab...46 Operation Settings Tab...48 Read and Fetch...48 Channels Tab...49 Operation Settings Tab...52 Initiate...52 Abort...52 Auto Setup...53 Get Information...53 Step Properties...55 IVI Fgen Step...56 Configure...57 Basic Tab...57 Channels Tab...60 Waveforms Tab...65 Sequences Tab...68 Extensions Tab...69 Operation Settings Tab...70 Initiate...70 Abort...71 Send Software Trigger...72 Get Information...72 Step Properties...74 IVI DC Power Supply Step...75 Configure...76 Channels Tab...76 Extensions Tab...80 Operation Settings Tab...81 Measure...81 Channels Tab...82 Initiate...83 Abort...83 Send Software Trigger...83 Reset Output Protection...83 Get Information...84 Step Properties...87 IVI Tools Step...88 Get Session Info...88 Init...90 Close...91 Reset...91 Self Test...91 Revision Query...93 Error Query...93 Get Error Info...95 Set/Get/Check Attributes...96 IVI Step Types 2 ni.com

3 Step Properties Overview TestStand provides several step types that enable you to configure and acquire data from IVI class compliant instruments. IVI is an instrument driver standard that provides common programming interfaces for several classes of instruments. IVI drivers exist for a number of popular instruments, including all applicable devices from National Instruments. For more information on IVI and IVI class compliant instrument drivers, see the National Instruments web site at ni.com TestStand includes the following IVI step types: Dmm Performs single-point and multipoint measurements with digital multimeters. Scope Performs single-point and waveform measurements with oscilloscopes. Fgen Generates predefined or custom waveforms using arbitrary waveform generators. DCPower Controls and monitors the output of DC power supplies. Tools Sets or gets instrument attributes and performs utility operations on any IVI instrument. IVI step types offer a configuration-based approach to instrument control. Typically, you use an initial step to configure an instrument and then perform measurements in one or more subsequent steps. TestStand references a session to an instrument using the instrument logical name. TestStand automatically initializes the instrument session when the instrument is first configured and automatically closes the instrument session when the execution is closed. If two executions reference the same logical name, the session is shared and the session closes when the last execution is released. To support the IVI step types, TestStand installs VISA, Measurement and Automation Explorer (MAX), and a set of basic IVI class drivers. TestStand installs one specific driver for each instrument class so that you can use specific driver simulation when your development machine does not connect to instruments. Note The basic class drivers do not support class level simulation or IVI class level API spying. To obtain fully functional IVI class drivers and a complete set of specific drivers, you can purchase version 1.1 or later of the IVI driver toolset. You can also download IVI specific drivers from ni.com National Instruments Corporation 3 IVI Step Types

4 Measurement & Automation Explorer (MAX) provides access to the National Instruments DAQ, GPIB, IMAQ, IVI, Motion, VISA, and VXI devices. Measurement & Automation Explorer allows you to configure your National Instruments hardware and software, add new channels, interfaces, and virtual instruments, execute system diagnostics, and view devices and instruments connected to your system. By default TestStand configures a sample logical name for each IVI class. The following figure shows the default IVI instruments defined in MAX. IVI step types complement but do not replace the instrument configuration and measurement operations you perform in code modules that you write using LabVIEW, Measurement Studio, Visual Basic, or other tools. Although IVI step types are the easiest way to configure and acquire data from IVI class instruments, you must use code modules to control instruments under the following circumstances: You need to precisely specify the instrument driver calls to ensure optimal performance. You need to call specific driver functions that an IVI class does not support. Your instrument does not conform to an IVI class or does not have an IVI driver. You need to interleave your instrument control operations with other code that must reside in a single code module. IVI Step Types 4 ni.com

5 Editing an IVI Step To use an IVI step, insert an IVI step for the class of instrument you want to control. To edit the step, right-click on the step and select Edit from the context menu. The following figure shows the Configure operation for the IVI Dmm step. Figure 1. Edit Dmm Step Dialog Box Each edit step dialog box contains a Logical Name control. The control selects a logical name or a virtual instrument name that you configure in Measurement and Automation Explorer (MAX). You can use the buttons to the right of the control to display the Browse for Expression dialog box and to launch Measurement and Automation Explorer. Each edit step dialog box contains an Operation control. The control specifies the action the step performs. Typical operations include configuring the instrument, taking a reading, or showing or hiding a graphical display panel for the instrument, also called a soft front panel. Depending on the instrument, you can also select other lower level actions National Instruments Corporation 5 IVI Step Types

6 Expression Controls such as Initiate, Send Software Trigger, or retrieve state information from the instrument. When you select an operation, the area under the operation control changes. Many operations group their settings on tab controls. In some cases, when TestStand configures an instrument, the instrument driver may coerce a settings value. Configuring an instrument might result in an invalid value error for a particular setting because the instrument-based values are not checked for validity until the configuration actually occurs. Once configure completes successfully, you can issue all of the other operations in subsequent steps. Most controls for settings accept expressions so you can either specify a literal value or an expression with variables and properties that TestStand evaluates at runtime. If you leave the expression empty, the operation does not update the setting value. This can be useful if you previously configured an instrument and all you want to do is change a few specific settings. You can use the browse button to the right of each control to display the Browse for Expression dialog box. Some expression controls use a ring control, which contains commonly used values. When you select an item from the ring, the control automatically displays the selected value. Many of the setting controls automatically check your expressions. Once the control looses focus, the control highlights syntax errors with red strikethrough text, and evaluation or type mismatch errors with red text. To display the error details, you can use the mouse to review the tooltip for the control as shown in the following figure. IVI Step Types 6 ni.com

7 Extensions The configure operation configures the instrument to match the settings as specified by the step. To enable instrument configuration controls that apply to features that IVI defines as class extensions, select from the Extensions tab the extended features that your instrument supports. The following figure shows the Extensions tab for the IVI Dmm step. Figure 2. Dmm Class Extension Tab The configure operation handles only those settings that are supported by the base class specification and the extension groups specified on the Extensions tab. For best results, enable only those extensions that are required for your application. National Instruments Corporation 7 IVI Step Types

8 Operation Settings Many of the operations, such as Configure and Fetch, allow you to specify where the dialog saves the operation settings for the step. For example, you could save the configure settings in a shared variable so that multiple steps could use the same settings. The following figure shows the Operation Settings tab for the configure operation. The Configuration Source control specifies the name of the property or variable where TestStand stores the settings when you select the OK button. The Load button reloads the settings from the specified property or variable location. IVI Step Types 8 ni.com

9 Validating a Configuration When you edit a step that configures an instrument, you can use the Validate button to test your configuration before closing the edit dialog box. For the IVI Dmm step type, the Validate button displays the following dialog box. The Validate IVI Configuration dialog box contains the following controls: Logical Name Selects a logical name or a virtual instrument name that you configure in Measurement and Automation Explorer (MAX). Configure Attributes Lists the settings to validate with the instrument. The Expression and Value controls display the settings for the currently selected setting. Show All When unchecked, the list control displays only the expressions that could not be evaluated. When checked, the list control displays all settings. Init Opens an IVI session to a virtual instrument. The Simulate checkbox specifies whether the instrument session uses simulation instead of talking directly to the instrument. Close Closes the instrument session. Reset Places the instrument in a known state by sending the command string *RST to the instrument. Configure Configures the instrument to match the state as specified by the specified settings. Show Soft Front Panel Displays the instrument soft front panel so that you can directly interact with the instrument. National Instruments Corporation 9 IVI Step Types

10 Using Soft Front Panels Each IVI session for an IVI step type can display a graphical display panel for the instrument, also called a soft front panel. The show and hide soft front panel operations control whether TestStand displays a soft front panel for the instrument. The following figure shows the soft front panel for the IVI Scope step. Figure 3. IVI Scope Step Soft Front Panel When the soft front panel is visible, you can interact directly with the instrument session that TestStand is controlling. IVI Step Types 10 ni.com

11 The following figure shows the SFP Options tab for the Show Soft Front Panel operation. The SFP Options tab for the Show Soft Front Panel operation contains the following controls: Allow Control Specifies whether the soft front panel responds to user input. Automatically Close Window When Execution is Released Specifies whether the soft front panel is closed when the execution is released. If not, the instrument session remains open until the soft front panel is closed. Allow User to Close Specifies whether the user can close the soft front panel window. National Instruments Corporation 11 IVI Step Types

12 Wait for User to Close Before Continuing Specifies whether the execution waits for the soft front panel to close before continuing to the next step. Auto Read Interval Specifies the rate at which the soft front panel reads or fetches measurements to update its display. This setting applies to the Dmm, Scope and DC Power Supply step types. The following figure shows the SFP Options tab for the Show Soft Front Panel operation. The Window Options tab for the Show Soft Front Panel operation contains the following controls: Window Title Specifies the title to display on the soft front panel window. Location Specifies the location and size of the soft front panel window. Show Modal Specifies that the soft front panel window is modal to the main application window. IVI Step Types 12 ni.com

13 The Operations Settings tab specifies to which property or variable the step saves the soft front panel operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Get Information You can use the Get Information operation for each instrument class step type to retrieve low-level status and information from the instrument. For the Get Information tab you must specify an expression that contains a variable or property to which the step assigns the retrieved value. In some cases, you must specify a channel name for the value to retrieve. Instrument Session Manager IVI step types use a software component called the Session Manager to share named instrument connections. You can use the Session Manager to share instrument connections in code modules that you write, even if you do not use IVI step types. For more information about the Session Manager, refer to the Session Manager help file in the National Instruments section of the Windows Start menu. Note Currently available drivers do not allow you to use the same instrument driver session in more than one operating system process simultaneously. IVI Dmm Step You use the IVI Dmm step type to perform single-point and multipoint measurements with digital multimeters. The step type supports the following operations: Configure Configures the instrument to match the state as specified by the step. Show Soft Front Panel Displays the soft front panel for the instrument. Hide Soft Front Panel Hides the soft front panel for the instrument. Read Initiates and returns a measurement from an instrument. Initiate Initiates a measurement. Fetch Returns the measured value from a measurement that the Initiate operation has started. Abort Cancels the wait for a trigger. Send SW Trigger Sends a software trigger command to trigger the instrument. Get Information Retrieves low-level status and information from the instrument. National Instruments Corporation 13 IVI Step Types

14 Configure The Configure operation configures the instrument to match the instrument state as specified by the step. Basic Tab The following figure shows the Basic tab for the Configure operation. The Basic tab for the Configure operation contains the following controls: Measurement Function Specifies the measurement function. The value of this setting determines the units for the Range and Resolution settings and the measurement values returned by the Read and Fetch operations. Supported values: DC Volts (1) Sets the DMM to measure DC voltage. AC Volts (2) Sets the DMM to measure AC voltage. DC Current (3) Sets the DMM to measure DC current. IVI Step Types 14 ni.com

15 AC Current (4) Resistance 2-wire (5) Resistance 4-wire (101) AC Plus DC Volts (106) Sets the DMM to measure AC current. Sets the DMM to measure 2-wire resistance. Sets the DMM to measure 4-wire resistance. Sets the DMM to measure AC voltage plus DC voltage. AC Plus DC Current (107) Sets the DMM to measure AC current plus DC current. Resolution Specifies the measurement resolution in absolute units of precision. The Measurement Function setting determines the units for resolution. If the Resolution value that you specify does not exactly match a value supported by an instrument driver, the instrument driver will coerce down to the next supported value. The digits of precision can be calculated from the Range and Resolution properties: Precision = Log 10 (Range/Resolution). Min AC Freq Specifies the minimum frequency component (in Hertz) of the input signal for AC measurements. If AC Min Freq does not exactly match a supported value by an instrument driver, the instrument driver will coerce down to the next supported value. The value of this setting affects instrument behavior only when the Measurement Function setting is set to an AC voltage or AC current measurement and the AC Measurement extension is enabled. Max AC Freq Specifies the maximum frequency component (in Hertz) of the input signal for AC measurements. If AC Max Freq does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. The value of this setting affects instrument behavior only when the Measurement Function setting is set to an AC voltage or AC current measurement and the AC Measurement extension is enabled. Trigger Source Specifies the trigger source. You can use a trigger to control when the DMM takes its measurement. The trigger s location is defined by the Trigger Source setting. Supported values: Immediate (1) Specifies that the DMM does not wait for a trigger before taking a measurement. External (2) Specifies that the DMM waits for a trigger on the external trigger input before taking a measurement. Software ( 3) Specifies that the DMM waits for a trigger until Send Software Trigger operation executes and then takes a measurement. National Instruments Corporation 15 IVI Step Types

16 TTL0 (111) Specifies that the DMM waits for a trigger on TTL0 before taking a measurement. TTL1 (112) Specifies that the DMM waits for a trigger on TTL1 before taking a measurement. TTL2 (113) Specifies that the DMM waits for a trigger on TTL2 before taking a measurement. TTL3 (114) Specifies that the DMM waits for a trigger on TTL3 before taking a measurement. TTL4 (115) Specifies that the DMM waits for a trigger on TTL4 before taking a measurement. TTL5 (116) Specifies that the DMM waits for a trigger on TTL5 before taking a measurement. TTL6 (117) Specifies that the DMM waits for a trigger on TTL6 before taking a measurement. TTL7 (118) Specifies that the DMM waits for a trigger on TTL7 before taking a measurement. ECL0 (119) Specifies that the DMM waits for a trigger on ECL0 before taking a measurement. ECL1 (120) Specifies that the DMM waits for a trigger on ECL1 before taking a measurement. PXI STAR (131) Specifies that the DMM waits for a trigger on the PXI Star trigger bus before taking a measurement. RTSI0 (140) Specifies that the DMM waits for a trigger on RTSI0 before taking a measurement. RTSI1 (141) Specifies that the DMM waits for a trigger on RTSI1 before taking a measurement. RTSI2 (142) Specifies that the DMM waits for a trigger on RTSI2 before taking a measurement. RTSI3 (143) Specifies that the DMM waits for a trigger on RTSI3 before taking a measurement. RTSI4 (144) Specifies that the DMM waits for a trigger on RTSI4 before taking a measurement. RTSI5 (145) Specifies that the DMM waits for a trigger on RTSI5 before taking a measurement. RTSI6 (146) Specifies that the DMM waits for a trigger on RTSI6 before taking a measurement. Range Specifies the measurement range. The Range setting is used only when the Range Mode setting is set to Use Specified Range. If Range value that you specify does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next IVI Step Types 16 ni.com

17 supported value. The Measurement Function setting determines the units of Range. The digits of precision can be calculated from the Range and Resolution properties: Precision = Log10(Range/Resolution). Supported values: Auto Range On ( 1) Auto Range Off ( 2) Sets the DMM to calculate the range before each measurement automatically. Disables autoranging. The DMM sets the range to the value it most recently calculated. Auto Range Once ( 3) Sets the DMM to calculate the range before the next measurement. The DMM uses this range value for all subsequent measurements. Use Specified Delay (0) Enables you to manually specify the measurement range. Trigger Delay Specifies the length of time in seconds between the DMM receiving the trigger and taking the measurement. Many DMMs have a small, nonzero value as the minimum value for trigger delay. To configure the instrument to use the shortest trigger delay, set this setting to zero. The driver will coerce any value between zero and the minimum Trigger Delay value that you specify to the minimum supported value. Trigger Delay is used only when the Trigger Delay Mode setting is set to Use Specified Delay. Supported values: Auto Delay On ( 1) Auto Delay Off ( 2) Use Specified Delay (0) Sets the DMM to calculate the trigger delay before each measurement. Stops the DMM from calculating the trigger delay and sets the trigger delay to the last trigger delay the DMM calculated. Enables you to manually specify the length of time in seconds between the DMM receiving the trigger and taking the measurement. National Instruments Corporation 17 IVI Step Types

18 Advanced Tab The following figure shows the Advanced tab for the Configure operation. The Advanced tab for the Configure operation contains the following controls: Sample Count Specifies the number of measurements the DMM takes each time it receives a trigger. The value of this setting affects instrument behavior only when the Multi Point extension is enabled. Sample Interval Specifies the interval between samples in seconds. This setting affects instrument behavior only when Sample Count is greater than 1, Sample Trigger is set to Interval ST, and the Multi Point extension is enabled. If Sample Interval does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. Trigger Count Specifies the number of triggers the DMM accepts before it returns to the idle state. The value of this setting affects instrument behavior only when the Multi Point extension is enabled. Sample Trigger Specifies the trigger source for each sample. The Sample Trigger setting is typically used when handshaking with a switching system. For example, you can set up a switching system to IVI Step Types 18 ni.com

19 go through a scan specified by a switch scan list and set up the DMM to take a measurement at each channel specified in the scan list. You can connect the DMM's VMC (voltmeter complete) signal to trigger input on the switching system. Also, the switching system can be set up so that once if finishes a step in its scan, it sends out a pulse on the scanner advanced line. That line can be hooked to the DMM's sample trigger. If the value of the Sample Count is greater than 1, the DMM waits until a sample trigger occurs after taking a single measurement. When the sample trigger specified by this setting occurs, the DMM takes the next measurement. This setting affects instrument behavior only when Sample Count is greater than 1 and the Multi Point extension is enabled. Supported values: Immediate (1) Specifies that the DMM does not wait for a trigger before acquiring a sample. External (2) Specifies that the DMM waits until a sample trigger occurs on the external trigger input and then acquires a sample. Software (3) Specifies that the DMM waits for a sample trigger until the Send Software Trigger operation executes and then acquires a sample. TTL0 (111) Specifies that the DMM waits until a sample trigger occurs on TTL0 and then acquires a sample. TTL1 (112) Specifies that the DMM waits until a sample trigger occurs on TTL1 and then acquires a sample. TTL2 (113) Specifies that the DMM waits until a sample trigger occurs on TTL2 and then acquires a sample. TTL3 (114) Specifies that the DMM waits until a sample trigger occurs on TTL3 and then acquires a sample. TTL4 (115) Specifies that the DMM waits until a sample trigger occurs on TTL4 and then acquires a sample. TTL5 (116) Specifies that the DMM waits until a sample trigger occurs on TTL5 and then acquires a sample. TTL6 (117) Specifies that the DMM waits until a sample trigger occurs on TTL6 and then acquires a sample. National Instruments Corporation 19 IVI Step Types

20 TTL7 (118) Specifies that the DMM waits until a sample trigger occurs on TTL7 and then acquires a sample. ECL0 (119) Specifies that the DMM waits until a sample trigger occurs on ECLO and then acquires a sample. ECL1 (120) Specifies that the DMM waits until a sample trigger occurs on ECL1 and then acquires a sample. PXI STAR (131) Specifies that the DMM waits until a sample trigger occurs on the PXI Star trigger bus and then acquires a sample. RTSI0 (140) Specifies that the DMM waits until a sample trigger occurs on RTSI0 and then acquires a sample. RTSI1 (141) Specifies that the DMM waits until a sample trigger occurs on RTSI1 and then acquires a sample. RTSI2 (142) Specifies that the DMM waits until a sample trigger occurs on RTSI2 and then acquires a sample. RTSI3 (143) Specifies that the DMM waits until a sample trigger occurs on RTSI3 and then acquires a sample. RTSI4 (144) Specifies that the DMM waits until a sample trigger occurs on RTSI4 and then acquires a sample. RTSI5 (145) Specifies that the DMM waits until a sample trigger occurs on RTSI5 and then acquires a sample. RTSI6 (146) Specifies that the DMM waits until a sample trigger occurs on RTSI6 and then acquires a sample. Interval (10) Specifies that the DMM waits for a sample trigger to occur for the amount of time specified by Sample Interval and then acquires a sample. Meas Complete Dest Specifies the destination of the measurement complete signal. After each measurement, the DMM generates a measurement complete signal. This signal is sometimes referred to as Voltmeter Complete. The value of this setting affects instrument behavior only when the Multi Point extension is enabled. IVI Step Types 20 ni.com

21 Supported values: None ( 1) External (2) TTL0 (111) TTL1 (112) TTL2 (113) TTL3 (114) TTL4 (115) TTL5 (116) TTL6 (117) TTL7 (118) ECL0 (119) ECL1 (120) PXI STAR (131) RTSI0 (140) RTSI1 (141) RTSI2 (142) RTSI3 (143) RTSI4 (144) RTSI5 (145) RTSI6 (146) Does not route the measurement complete signal. Routes the measurement complete signal to the external connector. Routes the measurement complete signal to TTL0. Routes the measurement complete signal to TTL1. Routes the measurement complete signal to TTL2. Routes the measurement complete signal to TTL3. Routes the measurement complete signal to TTL4. Routes the measurement complete signal to TTL5. Routes the measurement complete signal to TTL60. Routes the measurement complete signal to TTL7. Routes the measurement complete signal to ECL0. Routes the measurement complete signal to ECL 1. Routes the measurement complete signal to PXIStartriggerbus. Routes the measurement complete signal to RTSI0. Routes the measurement complete signal to RTSI1. Routes the measurement complete signal to RTSI2. Routes the measurement complete signal to RTSI3. Routes the measurement complete signal to RTSI4. Routes the measurement complete signal to RTSI5. Routes the measurement complete signal to RTSI6. National Instruments Corporation 21 IVI Step Types

22 Voltage Range for Freq Specifies the expected range of the amplitude of the input signal in volts RMS for frequency and period measurements. If the Voltage Range For Freq setting does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. The value of this setting affects instrument behavior only when the Frequency Measurement extension is enabled and the Measurement Function setting is set to a frequency or period measurement. Auto Zero Specifies the auto-zero mode. When the Auto Zero setting is enabled, the DMM internally disconnects the input signal and takes a zero reading. The DMM then subtracts the zero reading from the measurement to prevent offset voltages present in the instrument s input circuitry from affecting measurement accuracy. The value of this setting affects instrument behavior only when the Auto Zero extension is enabled. Supported values: Auto Zero Off (0) Disables the auto-zero feature. Auto Zero On (1) Configures the DMM to take a zero reading for each measurement. The DMM subtracts the zero reading from the value it measures. Auto Zero Once (2) Configures the DMM to take a zero reading immediately. The DMM then subtracts this zero reading from all subsequent values it measures. Powerline Freq Specifies the power line frequency in Hertz. Some devices require that the frequency of the power line that they are connected is specified for accurate measurements. The value of this setting affects instrument behavior only when the Powerline Frequency extension is enabled. Trigger Slope Specifies the polarity of the external trigger slope. The DMM triggers on either the rising or the falling edge of the external trigger source depending on the value of the Trigger Slope setting. The value of this setting affects instrument behavior only when the Trigger Slope extension is enabled. Supported values: Positive (0) Sets the trigger event to occur on the rising edge of the trigger pulse. Negative (1) Sets the trigger event to occur on the falling edge of the trigger pulse. IVI Step Types 22 ni.com

23 Temperature Tab The following figure shows the Temperature tab for the Configure operation. The Temperature tab for the Configure operation contains the following controls: Transducer Type Specifies the device used to measure the temperature. The value of this setting affects instrument behavior only when the Temperature Measurement extension is enabled and the Measurement Function setting is set to Temp. Supported values: Thermocouple (1) Sets the DMM to measure temperature using a thermocouple. Thermistor (2) Sets the DMM to measure temperature using a thermistor. National Instruments Corporation 23 IVI Step Types

24 2 Wire RTD (3) Sets the DMM to measure temperature using a 2-wire temperature resistance device. 4 Wire RTD (4) Sets the DMM to measure temperature using a 4-wire temperature resistance device. Thermistor Resistance Specifies the resistance of the thermistor in ohms. The value of this setting affects instrument behavior only when the Thermistor and Temperature Measurement extensions are enabled and the Transducer Type is set to Thermistor. Rtd Alpha Specifies the alpha parameter for a resistance temperature device (RTD). The value of this setting affects instrument behavior only when the RTD and Temperature Measurement extensions are enabled and the Transducer Type is set to 2 Wire RTD or 4 Wire RTD. Rtd Resistance Specifies the R0 parameter (resistance) for a resistance temperature device (RTD) in ohms. The RTD resistance is also known as the RTD reference value. The value of this setting affects instrument behavior only when the RTD and Temperature Measurement extensions are enabled and the Transducer Type is set to 2WireRTDor4WireRTD. Thermocouple Type Specifies the type of thermocouple used to measure the temperature. The value of this setting affects instrument behavior only when the Thermocouple and Temperature Measurement extensions are enabled and the Transducer Type is set to Thermocouple. B (1) Measures temperature from a B-type thermocouple. C (2) Measures temperature from a C-type thermocouple. D (3) Measures temperature from a D-type thermocouple. E (4) Measures temperature from a E-type thermocouple. G (5) Measures temperature from a G-type thermocouple. J (6) Measures temperature from a J-type thermocouple. K (7) Measures temperature from a K-type thermocouple. N (8) Measures temperature from a N-type thermocouple. IVI Step Types 24 ni.com

25 R (9) Measures temperature from a R-type thermocouple. S (10) Measures temperature from a S-type thermocouple. T (11) Measures temperature from a T-type thermocouple. U (12) Measures temperature from a U-type thermocouple. V (13) Measures temperature from a V-type thermocouple. Reference Junction Type Specifies the type of reference junction to be used in the reference junction compensation of a thermocouple measurement. Supported values: Internal (1) Sets the DMM to use an internal sensor at the thermocouple junction for the junction compensation. Fixed (2) Sets the DMM to use a fixed value for the thermocouple junction compensation. National Instruments Corporation 25 IVI Step Types

26 Extensions Tab The following figure shows the Extensions tab for the Configure operation. The Extensions tab for the Configure operation contains the following controls. AC Measurement Supports the IviDmmACMeasurement extension group. Frequency Measurement Supports the IviDmmFrequencyMeasurement extension group. Temperature Measurement Supports the IviDmmTemperatureMeasurement extension group. Multi Point Supports the IviDmmMultiPoint extension group. Trigger Slope Supports the IviDmmTriggerSlope extension group. Software Trigger Supports the IviDmmSoftwareTrigger extension group. Device Info Supports the IviDmmDeviceInfo extension group. Auto Range Value Supports the IviDmmAutoRangeValue extension group. IVI Step Types 26 ni.com

27 Auto Zero Supports the IviDmmAutoZero extension group. Powerline Frequency Supports the IviDmmPowerLineFrequency extension group. Operation Settings Tab The Operations Settings tab specifies to which property or variable the step saves the operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Read and Fetch The Read operation initiates and returns a measurement from an instrument. Read is a higher-level acquisition operation that encapsulates some of the details of using the Initiate and Fetch operations. If Sample Count setting is greater than 1 and the Multi Point extension is enabled, the Read operation returns an array of values. Otherwise the operation returns a single value. The returned value is either the actual reading in units defined by the Measurement Function setting, or a value indicating that an overrange condition occurred. If an overrange condition occurs, the reading parameter contains an IEEE-defined NaN (not a number) value. To test a value for the overrange condition, specify a status expression in the Set Status if Over-Range control. If Timeout seconds occur before the Read operation completes, the Set Status on Timeout control determines the step status. The Fetch operation returns the measured value from a measurement that the Initiate operation started. If Trigger Count is greater than 1 and the Multi Point extension is enabled, the Fetch operation returns an array of values. Otherwise it returns a single value. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Initiate operation. Before issuing a Fetch operation, use the Initiate operation in a separate step to initiate a measurement. If you perform other operations on the instrument after the call to an Initiate operation but prior to issuing a Fetch operation, the Fetch operation might not return valid data. National Instruments Corporation 27 IVI Step Types

28 The following figure shows the Read operation. The Read operation contains the following controls: Data Type Specifies whether the step expects a single value or array of values. The step coerces the data type of the Step.Result.Reading property to NI_IviSinglePoint or NI_IviWave, respectively. Measurement Destination Specifies a variable or property to which the step assigns the measurement value. For single values, the data type of the variable or property must be Number or NI_IviSinglePoint. For array of values, the data type of the variable or property must be array of Number or NI_IviWave. The default configuration for the step specifies Step.Result.Reading as the destination. When you edit the step, the step automatically coerces the data type of the Step.Result.Reading property to NI_IviSinglePoint or NI_IviWave, based on the value of the Data Type control. If you do not specify Step.Result.Reading as the destination, TestStand still copies the measurement value to the Step.Result.Reading.Data property at runtime unless the Copy Data to Execution Results is unchecked. Timeout Specifies the timeout in milliseconds for the operation. The Timeout setting applies to the length of time between initializing a call to Read and completing the data acquisition, not the time required by IVI Step Types 28 ni.com

29 the DMM for computations or to transfer data across the instrumentation bus. To set an infinite timeout, set the Timeout setting to 1. Set Status on Timeout Specifies the status for the step result if a timeout condition occurs. If you leave this control blank, the step ignores timeout conditions. Set Status on Over-Range Specifies the status for the step result if a timeout condition occurs. If you leave this control blank, the step does not check for an overrange condition. Copy Data To Execution Results Specifies whether the TestStand copies the measurement value stored in the property Step.Result.Reading.Data to the step result. If you enable this control, TestStand cannot include the measurement in a report or log the measurement to database. For single-point measurements, this setting is always checked. Initiate Abort Send SW Trigger Get Information The Initiate operation initiates a measurement. When this operation executes, the DMM leaves the idle state and waits for a trigger. Use the Fetch operation to retrieve the measurement that was started by the Initiate operation. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Fetch operation. The Abort operation aborts a previously initiated measurement and returns the instrument to the idle state. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Initiate operation. The Send SW Trigger operation sends a software trigger command to trigger the instrument. This operation affects the behavior of the instrument if the Trigger Source setting is set to Software Trig and the Software Trigger extension is enabled. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Initiate operation. The Get Information operation retrieves low-level status and information from the instrument. National Instruments Corporation 29 IVI Step Types

30 The following figure shows the Get Information operation. The Get Information operation contains the following controls: Get Auto Range Value Specifies a variable or property to which the step assigns the range value when the DMM is autoranging. When the Range Mode setting is set to Auto Range On, the Range setting does not accurately reflect the current range. If you are autoranging the DMM, use this control to retrieve the range that the instrument has set itself to. Get Aperture Time Info Returns information about the aperture time. This operation works only on instrument drivers that support the Device Info Ext extension. Time Specifies a variable or property to which the step assigns the aperture time, also known as the integration time. Units of aperture time are returned by the Units control. Units Specifies a variable or property to which the step assigns the units of aperture time. A value of 1 specifies the aperture time is in powerline cycles. A value of 0, specifies the aperture time is in seconds. IVI Step Types 30 ni.com

31 Step Properties Figure 4 shows the step properties for the IVI Dmm step type. Figure 4. IVI Dmm Step Properties National Instruments Corporation 31 IVI Step Types

32 IVI Scope Step The IVI Dmm step type defines the following step properties in addition to the common custom properties: Step.Result.Reading contains the measurement values for the Read and Fetch operations. The property data type is either NI_IviSinglePoint or NI_IviWave. Step.Logical.Name contains the logical name expression. Step.InstrOperation contains a value that specifies the operation the step is set to perform. Step.SettingSource contains the name of the property or variable where the step loads and stores the settings for the operation. Step.Configuration contains the settings for the Configure operation. The data type of this property is NI_IviDmmConfig. Step.SoftFrontPanel contains the settings for the Show Soft Front Panel operation. The data type of this property is NI_IviSoftFrontPanel. Step.Readings contains the settings for the Read and Fetch operations. Step.GetInfo contains the settings for the Get Information operation. You use the IVI Scope step type to acquire a voltage waveform from an analog input signal with oscilloscopes. The step type supports the following operations. Configure Configures the instrument to match the state as specified by the step. Show Soft Front Panel Displays the soft front panel for the instrument. Hide Soft Front Panel Hides the soft front panel for the instrument. Read Initiates and returns a measurement from an instrument. Initiate Initiates a measurement. Fetch Returns the measured value from a measurement that the Initiate operation has started. Abort Cancels the wait for a trigger. Auto Setup Performs an automatic setup on the instrument. Get Information Retrieves low-level status and information from the instrument. IVI Step Types 32 ni.com

33 Configure The Configure operation configures the instrument to match the instrument state as specified by the step. Basic Tab The following figure shows the Basic tab for the Configure operation. The Basic tab for the Configure operation contains the following controls: Measurement Function Specifies how the oscilloscope acquires data and fills the waveform record. Supported values: Normal (0) Configures the oscilloscope to acquire one sample for each point in the waveform record. The oscilloscope uses real-time or equivalent time sampling. Peak Detect (1) Sets the oscilloscope to the peak-detect acquisition mode. The oscilloscope oversamples the input signal and keeps the minimum and maximum values that National Instruments Corporation 33 IVI Step Types

34 correspond to each position in the waveform record. The oscilloscope uses only real-time sampling. Hi Res (2) Configures the oscilloscope to oversample the input signal. The oscilloscope calculates the average value that corresponds to each position in the waveform record. The oscilloscope uses only real-time sampling. Envelope (3) Sets the oscilloscope to the envelope acquisition mode. The oscilloscope acquires multiple waveforms and keeps the minimum and maximum voltages it acquires for each point in the waveform record. Specify the number of waveforms the oscilloscope acquires with the Num Envelopes setting. The oscilloscope can use real-time or equivalent-time sampling. Average (4) Configures the oscilloscope to acquire multiple waveforms and calculate the average value for each point in the waveform record. Specify the number of waveforms to acquire with the Num Averages setting. The oscilloscope uses real-time or equivalent time sampling. Interpolation Specifies the interpolation method the oscilloscope uses when it cannot resolve a voltage for every point in the waveform record. The value of this setting affects instrument behavior only when the interpolation extension is enabled. Support values: No Interpolation (1) Specifies that the oscilloscope does not interpolate points in the waveform. Instead, the driver sets every element in the waveform record for which the oscilloscope cannot receive a value to an IEEE-defined NaN (not a number) value. Sine X (2) Specifies that the oscilloscope uses a sin(x)/x calculation to interpolate a value when it cannot resolve a voltage in the waveform record. Linear (3) Specifies that the oscilloscope uses a linear approximation to interpolate a value when it cannot resolve a voltage in the waveform record. IVI Step Types 34 ni.com

35 Num Averages Specifies the number of waveforms the oscilloscope acquires and averages. After the oscilloscope acquires as many waveforms as this setting specifies, it returns to the idle state. The value of this setting affects instrument behavior only when the Average Acquisition extension is enabled and the Acquisition Type is set to Average. Num Envelopes Specifies the number of waveforms the oscilloscope acquires and analyzes to create the minimum and maximum waveforms. When you set the Acquisition Type setting to Envelope, the oscilloscope acquires multiple waveforms. After each waveform acquisition, the oscilloscope keeps the minimum and maximum values it finds for each point in the waveform record. The Num Envelopes setting specifies the number of waveforms the oscilloscope acquires and analyzes to create the minimum and maximum waveforms. After the oscilloscope acquires as many waveforms as this setting specifies, it returns to the idle state. The value of this setting affects instrument behavior only when you enable the Min Max Waveform extension and set the Acquisition Type setting to Envelope. Horizontal Min Num Points Specifies the minimum number of points the end user requires in the waveform record for each channel. The instrument driver uses the value that you specify to configure the record length that the oscilloscope uses for waveform acquisition. If the instrument cannot support the requested record length, the driver must configure the instrument to the closest supported record length. The value of the supported record length will be larger than the requested length. Use the Get Actual Record Length operation to get the actual record length for the acquisition. Horizontal Time Per Record Specifies the length of time in seconds that corresponds to the record length. If Time Per Record does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. Horizontal Acq Start Time Specifies the length of time in seconds from the trigger event to the first point in the waveform record. If the Acquisition Start Time value is positive, the first point in the waveform record occurs after the trigger event. If the value is negative, the first point in the waveform record occurs before the trigger event. National Instruments Corporation 35 IVI Step Types

36 Advanced Tab The following figure shows the Advanced tab for the Configure operation. The Advanced tab for the Configure operation contains the following controls: Low Reference Specifies the low reference that the oscilloscope uses for waveform measurements. The value is a percentage of the difference between Voltage High and Voltage Low. The value of this setting affects instrument behavior only when the Waveform Measurement extension is enabled. Middle Reference Specifies the middle reference in percentage that the oscilloscope uses for waveform measurements. The value is a percentage of the difference between Voltage High and Voltage Low. The value of this setting affects instrument behavior only when the Waveform Measurement extension is enabled. High Reference Specifies the high reference that the oscilloscope uses for waveform measurements. The value is a percentage of the difference between Voltage High and Voltage Low. The value of this setting affects instrument behavior only when the Waveform Measurement extension is enabled. IVI Step Types 36 ni.com

37 Channels Tab The following figure shows the Channels tab for the Configure operation. The Channels tab contains a list control with the default channels for the selected logical name. You can use the Add and Remove buttons to add new channels and remove existing channels from the list. You can specify whether the oscilloscope acquires a waveform for the channel by enabling the channel using the check box within the list control. If you enable the Preserve Existing Channels checkbox, the step adds to or modifies any existing channels previously configured. When you uncheck the Preserve Existing Channels check box, the step deletes all previously configured channels before configuring the specified channels in the list. The Channels tab for the Configure operation contains the following channel specific controls: Name Specifies the name of the channel. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. Vertical Coupling Specifies how the oscilloscope couples the input signal for the channel. National Instruments Corporation 37 IVI Step Types

38 Supported values: AC (0) DC (1) Gnd (2) Specifies that the oscilloscope AC couples the input signal. Specifies that the oscilloscope DC couples the input signal. Specifies that the oscilloscope couples the channel to the ground. Vertical Range Specifies the absolute value of the input range in volts for a channel. For example, to acquire a sine wave that spans between 5.0 and 5.0 volts, set the value to 10.0 volts. If Vertical Range does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. Vertical Offset Specifies the center of the range in volts specified by the Vertical Range setting. This setting value is set with respect to ground in volts. For example, to acquire a sine wave that spans between 0.0 and 10.0 volts, set vertical offset to 5.0 volts. Max Input Freq Specifies the maximum frequency for the input signal you want the instrument to accommodate without attenuating it by more than 3dB. If the bandwidth limit frequency of the instrument is greater than this maximum frequency, the driver enables the bandwidth limit to attenuate the input signal by at least 3dB at frequencies greater than the bandwidth limit. If Max Input Frequency does not exactly match a supported value by an instrument driver, the instrument driver will coerce up to the next supported value. Probe Attenuation Specifies the scaling factor that the probe attached to the channel uses to attenuate the input. If the value is 1, the oscilloscope is configured to use automatic probe sensing. If the value is positive, the oscilloscope is configured to use the specified manual probe attenuation. For example, for a 10:1 probe, set this setting to If you are using automatic probe sensing, use the Get Auto Probe Sense Value operation to determine the actual probe. Input Impedance Specifies the input impedance for the channel in ohms. Common values are 50.0, 75.0, and 1,000, IVI Step Types 38 ni.com

39 Trigger Tab The following figure shows the Trigger tab for the Configure operation. The Trigger tab for the Configure operation contains the following controls: Type Specifies the event that triggers the oscilloscope. Supported values: AC Line (7) Configures the oscilloscope for AC Line triggering. Edge (1) Configures the oscilloscope for edge triggering. An edge trigger occurs when the trigger signal specified with the Trigger Source setting passes the voltage threshold specified with the Trigger Level setting and has the slope specified with the Trigger Slope setting. Glitch (4) Configures the oscilloscope for glitch triggering. National Instruments Corporation 39 IVI Step Types

40 Immediate (6) Configures the oscilloscope for immediate triggering. The oscilloscope does not wait for a trigger of any kind upon initialization. Runt (3) Configures the oscilloscope for runt triggering. TV (5) Configures the oscilloscope for triggering on TV signals. Width (2) Configures the oscilloscope for width triggering. Source Specifies the source that the oscilloscope monitors for the trigger event. Source is a string that can be a defined virtual channel name, an instrument specific channel string, or one of the following defined values: IVISCOPE_VAL_EXTERNAL IVISCOPE_VAL_GPIB_GET IVISCOPE_VAL_TTL0 IVISCOPE_VAL_TTL1 IVISCOPE_VAL_TTL2 IVISCOPE_VAL_TTL3 IVISCOPE_VAL_TTL4 IVISCOPE_VAL_TTL5 IVISCOPE_VAL_TTL6 IVISCOPE_VAL_TTL7 IVISCOPE_VAL_ECL0 IVISCOPE_VAL_ECL1 IVISCOPE_VAL_PXI_STAR IVISCOPE_VAL_RTSI_0 IVISCOPE_VAL_RTSI_1 IVISCOPE_VAL_RTSI_2 IVISCOPE_VAL_RTSI_3 IVISCOPE_VAL_RTSI_4 IVISCOPE_VAL_RTSI_5 IVISCOPE_VAL_RTSI_6 Holdoff Specifies the length of time in seconds the oscilloscope waits after it detects a trigger until the oscilloscope enables the trigger subsystem to detect another trigger. The Holdoff setting affects instrument operation only when the oscilloscope requires multiple acquisitions to build a complete waveform. The oscilloscope requires multiple waveform acquisitions when it uses equivalent time sampling or when the Acquisition Type is set to Envelope or Average. Many IVI Step Types 40 ni.com

41 scopes have a small, nonzero value as the minimum value for this setting. To configure the instrument to use the shortest trigger holdoff, specify a value of zero. The instrument driver will coerce any value between zero and the minimum value you specify to the minimum supported value. Coupling Specifies how the oscilloscope couples the trigger source. Supported values: AC (0) Specifies that the oscilloscope AC couples the trigger signal. DC (1) Specifies that the oscilloscope DC couples the trigger signal. HF Reject (3) Specifies that the oscilloscope filters out the high frequencies from the trigger signal. LF Reject (4) Specifies that the oscilloscope filters out the low frequencies from the trigger signal. Noise Reject (5) Specifies that the oscilloscope filters out the noise from the trigger signal. Modifier Determines the oscilloscope's behavior in the absence of the configured trigger. The value of this setting affects instrument behavior only when the Trigger Modifier extension is enabled. Supported values: Auto (2) Specifies that the oscilloscope automatically triggers if the configured trigger does not occur within the timeout period. Auto Level (3) Specifies that the oscilloscope adjusts the trigger level if the trigger you specify does not occur. No Trigger Mod (1) Specifies that the oscilloscope wait until the specified trigger occurs. Initiate Continuous Continuously initiates waveform acquisition when set to True. The value of this setting affects instrument behavior only when the Continuous Acquisition extension is enabled. This setting does not affect the behavior of the Read and Fetch operations because these operations are instrument specific. Set this setting to True when you need continuous updates of the oscilloscope display. Level Specifies a level setting for the following trigger types. Edge Specifies the threshold in volts for the trigger subsystem. The value of this setting affects instrument behavior only when the Trigger Type is Edge. National Instruments Corporation 41 IVI Step Types

42 Glitch Specifies the threshold in volts for the trigger subsystem. The value of this setting affects instrument behavior only when the Glitch Trigger extension is enabled and the Trigger Type setting is set to Glitch. Width Specifies the level in volts at which the pulse causes a trigger. The value of this setting affects instrument behavior only when the Width Trigger extension is enabled and the Trigger Type setting is set to Width. Condition Specifies the condition for the following trigger types. Glitch Specifies the range in which the glitch trigger occurs. This setting determines if the glitch trigger happens when the oscilloscope detects a pulse with a width less than or greater than the width value. The value of this setting affects instrument behavior only when the Glitch Trigger extension is enabled and the Trigger Type setting is set to Glitch. Supported values: Greater Than (2) Triggers the oscilloscope when the pulse width is greater than the value you specify with the Glitch Width setting. Less Than (1) Triggers the oscilloscope when the pulse width is less than the value you specify with the Glitch Width setting. Width Specifies if a pulse that is inside or outside the high and low thresholds triggers the oscilloscope. The value of this setting affects instrument behavior only when the Width Trigger extension is enabled and the Trigger Type setting is set to Width. Supported values: Width Outside (2) Configures the oscilloscope to trigger on pulses that have a width that is either greater than the high threshold or less than a low threshold. You can specify the high and low thresholds with the High Threshold and Low Threshold settings. Width Within (1) Configures the oscilloscope to trigger on pulses that have a width that is less than the high threshold and greater than the low threshold. You can specify the high and low thresholds with the High Threshold and Low Threshold settings. IVI Step Types 42 ni.com

43 Event Specifies the event on which the oscilloscope triggers. The value of this setting affects instrument behavior only when the TV Trigger extension is enabled and the Trigger Type setting is set to TV. Supported Values: Any Field (3) Sets the oscilloscope to trigger on any field. Any Line (4) Sets the oscilloscope to trigger on any line. Field1 (1) Sets the oscilloscope to trigger on field 1 of the video signal. Field2 (2) Sets the oscilloscope to trigger on field 2 of the video signal. Line Number (5) Sets the oscilloscope to trigger on any line. Line Number Specifies the line on which the oscilloscope triggers. The line number setting is independent of the field. To trigger on the first line of the second field, you must configure the line number to the value of 263 (if you presume that the first field has 262 lines). The value of this setting affects instrument behavior only when the TV Trigger extension is enabled, the Trigger Type setting is set to TV, and the TV Event setting is set to TV Line Number. Signal Format Specifies the format of TV signal on which the oscilloscope triggers. The value of this setting affects instrument behavior only when the TV Trigger extension is enabled and the Trigger Type setting is set to TV. Supported values: NTSC (1) Configures the oscilloscope to trigger on the NTSC signal format. PAL (2) Configures the oscilloscope to trigger on the PAL signal format. SECAM (3) Configures the oscilloscope to trigger on the SECAM signal format. Polarity Specifies a polarity setting for the following trigger types. Glitch Specifies the polarity of the glitch. The value of this setting affects instrument behavior only when the Glitch Trigger extension is enabled and the Trigger Type setting is set to Glitch. Supported values: Positive (1) Triggers the oscilloscope on a positive glitch. Negative (2) Triggers the oscilloscope on a negative glitch. Either (3) Triggers the oscilloscope on either a positive or negative glitch. National Instruments Corporation 43 IVI Step Types

44 Runt Specifies the polarity of the runt that triggers the oscilloscope. The value of this setting affects instrument behavior only when the Runt Trigger extension is enabled and the Trigger Type setting is set to Runt. Supported values: Positive (1) Triggers the oscilloscope on a positive runt. A positive runt occurs when a rising edge crosses the low runt threshold and does not cross the high runt threshold before recrossing the low runt threshold. Negative (2) Triggers the oscilloscope on a negative runt. A negative runt occurs when a falling edge crosses the high runt threshold and does not cross the low runt threshold before recrossing the high runt threshold. Either (3) Triggers the oscilloscope on either a positive or negative runt. TV Specifies the polarity of the TV signal. The value of this setting affects instrument behavior only when the TV Trigger extension is enabled and the Trigger Type setting is set to TV. Supported values: Negative (0) Configures the oscilloscope to trigger on a negative video sync pulse. Positive (1) Configures the oscilloscope to trigger on a positive video sync pulse. Width Specifies the polarity of the pulse that triggers the oscilloscope. The value of this setting affects instrument behavior only when the Width Trigger extension is enabled and Trigger Type is Width. Supported values: Negative (2) Configures the oscilloscope to trigger on negative pulses that have a width that meets the condition specified with the Condition setting. Positive (1) Configures the oscilloscope to trigger on positive pulses that have a width that meets the condition specified with the Condition setting. IVI Step Types 44 ni.com

45 Slope Specifies a slope setting for the following trigger type. AC Line Specifies the slope of the zero crossing upon which the scope triggers. The value of this setting affects instrument behavior only when the AC Line Trigger extension is enabled and the Trigger Type setting is set to AC Line. Supported values: Positive (1) Configures the oscilloscope to trigger on positive slope zero crossings of the network supply voltage. Negative (2) Configures the oscilloscope to trigger on negative slope zero crossings of the network supply voltage. Either (3) Configures the oscilloscope to trigger on either positive or negative slope zero crossings of the network supply voltage. Edge Specifies whether a rising or falling edge triggers the oscilloscope. The value of this setting affects instrument behavior only when the Trigger Type is Edge. Support values: Negative (0) Specifies that a negative (falling) edge passing through the trigger level triggers the oscilloscope. Positive (1) Specifies that a positive (rising) edge passing through the trigger level triggers the oscilloscope. Width Specifies the width setting for the following trigger types. Glitch Specifies the glitch width in seconds. The oscilloscope triggers when it detects a pulse with a width less than or greater than this value, depending on the value of the Glitch Condition setting. The value of this setting affects instrument behavior only when the Glitch Trigger extension is enabled and the Trigger Type setting is set to Glitch. High Threshold Specifies the high threshold for the following trigger types. Runt Specifies the high threshold in volts that the oscilloscope uses for runt triggering. The value of this setting affects instrument behavior only when the Runt Trigger extension is enabled and the Trigger Type setting is set to Runt. Width Specifies the high width threshold time in seconds. For the instrument to trigger, the pulse length must be between the High Threshold and Low Threshold values. The value of this National Instruments Corporation 45 IVI Step Types

46 setting affects instrument behavior only when the Width Trigger extension is enabled and the Trigger Type setting is set to Width. Low Threshold Specifies the high threshold for the following trigger types. Runt Specifies the low threshold in volts that the oscilloscope uses for runt triggering. The value of this setting affects instrument behavior only when the Runt Trigger extension is enabled and the Trigger Type setting is set to Runt. Width Specifies the low width threshold time in seconds. For the instrument to trigger, the pulse length must be between the High Threshold and Low Threshold values. The value of this setting affects instrument behavior only when the Width Trigger extension is enabled and the Trigger Type setting is set to Width. Extensions Tab The following figure shows the Extensions tab for the Configure operation. IVI Step Types 46 ni.com

47 The Extensions tab for the Configure operation contains the following controls: TV Trigger Supports extensions for oscilloscopes capable of triggering on TV signals. Runt Trigger Supports extensions for oscilloscopes with the capability to trigger on runt pulses. A runt condition occurs when the oscilloscope detects a positive or negative going pulse that crosses one voltage threshold but fails to cross a second threshold before recrossing the first. You can select whether a positive runt, negative runt, or either runt type triggers the acquisition. Glitch Trigger Supports extensions for oscilloscopes that can trigger on a glitch pulses. A glitch occurs when the oscilloscope detects a pulse width that is less than or a greater than a specified glitch duration. You can select whether a positive glitch, negative glitch, or either glitches trigger the acquisition. Width Trigger Supports extensions for oscilloscopes capable of triggering on user-specified pulse widths. Width triggering occurs when the oscilloscope detects a positive or negative pulse with a width between, or optionally outside, the user-specified threshold. AC Line Trigger Supports extensions for oscilloscopes that are capable of synchronizing the trigger with the AC Line. AC Line triggering occurs when the oscilloscope detects a positive zero crossing, negative zero crossing, or optionally either positive or negative zero crossing on the network supply voltage. Trigger Modifier Supports extensions for oscilloscopes that can specify the behavior of the triggering subsystem in the absence of the configured trigger. Waveform Measurement Supports extensions for oscilloscopes capable of calculating various measurements, such as rise-time, fall-time, period, and frequency, from an acquired waveform. Min Max Waveform Supports extensions for oscilloscopes that can acquire minimum and maximum waveforms that correspond to the same range of time. The two most common acquisition types in which oscilloscopes return minimum and maximum waveforms are envelope and peak detect. Average Acquisition Supports extensions for oscilloscopes that can perform the average acquisition. Interpolation Supports extensions for oscilloscopes capable of interpolating values in the waveform record that the oscilloscope's acquisition subsystem was unable to digitize. Probe Auto Sense Supports extensions for oscilloscopes that can return the probe attenuation of the attached probe. National Instruments Corporation 47 IVI Step Types

48 Sample Mode Supports extensions for oscilloscopes that can return whether the scope is using equivalent time or real time sampling to acquire waveform. Auto Setup Supports extensions for oscilloscopes that can perform an auto setup operation. Continuous Acquisition Supports extensions for oscilloscopes that can perform a continuous acquisition. Operation Settings Tab The Operations Settings tab specifies to which property or variable the step saves the operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Read and Fetch The Read operation initiates an acquisition and retrieves the measured value(s) from a previously started acquisition for the listed channels. Read initiates a new measurement on all channels. You can obtain data from multiple channels or different types of data from a single channel based on single trigger condition. The returned value is either the actual reading (in units defined by the Waveform Type, or a value indicating that an overrange condition occurred. If an overrange condition occurs, the reading parameter contains an IEEE-defined NaN (not a number) value. To test a value for the overrange condition, enable the Set Status if Over-Range control. If Timeout seconds occur before the Read operation completes, the Set Status on Timeout control determines the step status. The Fetch operation retrieves the measured value(s) from a previously started acquisition for the listed channels. Before calling Fetch, use the Initiate operation or use the Read operation on any channel to initiate a measurement. You can use the Fetch operation multiple times on a channel to retrieve different types of data from the same acquisition. This operation does not check the instrument status. Typically, the Fetch operation is called only in a sequence of calls to other low-level driver operations, such as the Initiate operation. IVI Step Types 48 ni.com

49 Channels Tab The following figure shows the Read operation. The Channels tab contains a list control with the default channels for the selected logical name. You can use the Add and Remove buttons to add new channels and remove existing channels from the list. You can specify whether the oscilloscope acquires a waveform for the channel by enabling the channel using the check box within the list control. The Channels tab for the Read operation contains the following channel specific controls: Name Specifies the name of the channel to read. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. Waveform Type Specifies the type of data to retrieve from the oscilloscope. Depending on this value, the returned data is a single value (for a measurement), a one-dimensional array (Waveform), or a two-dimensional array (Waveform Min Max). Supported values: Amplitude (15) High Voltage less the Low Voltage in volts over the entire waveform. National Instruments Corporation 49 IVI Step Types

50 Negative Duty Cycle (13) Ratio of the Negative Width to the Period of an integer number of cycles in the waveform expressed as a percentage. Positive Duty Cycle (14) Ratio of the Positive Width to the Period of anintegernumberofcyclesinthe waveform expressed as a percentage. Fall Time (1) Length of time in seconds for a falling edge of the signal to fall from the high reference level to the low reference level. Frequency (2) Frequency in hertz of one complete cycle in the waveform. Overshoot (18) Relative waveform distortion that follows an edge transition. Period (3) Length of time in seconds of one complete cycle in the waveform. Preshoot (19) Relative waveform distortion that precedes an edge transition. Rise Time (0) Length of time in seconds for a rising edge of the signal to rise from the low reference level to the high reference level. Average Voltage (10) Arithmetic average in volts measured over the entire waveform. Cycle Average Voltage (17) Arithmetic average in volts over an integer number of cycles in the waveform. Cycle Rms Voltage (16) True Root Mean Square (RMS) voltage overanintegernumberofcyclesinthe waveform. High Voltage (8) Voltage that corresponds to 100% when using the reference levels. The oscilloscope calculates this value using either the min/max or histogram methods. The min/max method uses the maximum value found. The histogram method uses a common value found above the middle of the waveform. Low Voltage (9) Voltage that corresponds to 0% when using the reference levels. The oscilloscope calculates this value using either the min/max or histogram methods. The min/max method uses the minimum value found. The histogram method uses a IVI Step Types 50 ni.com

51 Max Voltage (6) Min Voltage (7) Peak To Peak Voltage (5) Rms Voltage (4) Negative Width (11) Positive Width (12) Waveform ( 1) common value found below the middle of the waveform. The units are volts. Maximum amplitude in volts found in the entire waveform. Minimum amplitude in volts found in the entire waveform. Absolute difference in volts between the Max Voltage and the Min Voltage. True Root Mean Square (RMS) voltage of the entire waveform. Length of time in seconds between the mid-reference level points of a negative pulse in the waveform. Length of time in seconds between the mid-reference level points of a positive pulse in the waveform. Specifies that the Read/Fetch operation acquires a waveform with the current configuration. If specified, Read returns a one-dimensional array of points. Min/Max ( 2) Specifies that the Read/Fetch operation acquires a min-max waveform (two-dimensional array). This constant is valid only if Acquisition Type is set to Peak Detect or Envelope. Data Type Specifies whether the step expects a single value, array ofvalues,orwavepair.thestepcoercesthedatatypeoftheelements in the array property, Step.Result.Reading, to NI_IviSinglePoint, NI_IviWave, or NI_IviWavePair respectively. Measurement Destination Specifies a variable or property to which the step assigns the measurement value. For single values, the data type of the variable or property must be Number or NI_IviSinglePoint. For array of values, the data type of the variable or property must be array of Number or NI_IviWave. For a wave pair, the data type of the variable or property must be 2D array of Number or NI_IviWavePair. The default configuration for the step specifies Step.Result.Reading as the destination. This property is an array of container, and the size of the array is equal to the number of channels specified for the Read or Fetch operation. When you edit the step, the step automatically resized the array and coerces the data type of each element of the array to NI_IviSinglePoint, NI_IviWave or NI_IviWavePair, based on the value of the Data Type control for each channel. If you do not specify Step.Result.Reading as the destination, TestStand still copies the National Instruments Corporation 51 IVI Step Types

52 measurement value to the Data subproperty in each array element at runtime unless the Copy Data to Execution Results is unchecked. Set Status on Over-Range Specifies the status for the step result if a timeout condition occurs. If you leave this control blank, the step does not check for an overrange condition. Copy Data To Execution Results Specifies whether the TestStand copies the measurement value stored in the property Step.Result.Reading.Data to the step result. If you enable this control, TestStand cannot include the measurement in a report or log the measurement to database. For single-point measurements, this setting is always checked. The Timeout control specifies the timeout in milliseconds for the operation. The Timeout setting applies to the length of time between initializing a call to Read and completing the data acquisition, not the time required by the instrument for computations or to transfer data across the instrumentation bus. To set an infinite timeout, set the Timeout setting to 1. The Set Status on Timeout control specifies the status for the step result if a timeout condition occurs. If you leave this control blank, the step ignores timeout conditions. Operation Settings Tab The Operations Settings tab specifies to which property or variable the step saves the operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Initiate Abort The Initiate operation initiates an acquisition. After calling this operation, the oscilloscope leaves the idle state and waits for a trigger. The oscilloscope acquires a waveform for each enabled channel. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Fetch operation. The Abort operation aborts a previously initiated measurement and returns the instrument to the idle state. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations, such as the Initiate operation. IVI Step Types 52 ni.com

53 Auto Setup Get Information The Auto Setup operation performs an automatic setup on the instrument. Performing an automatic setup causes the instrument to put itself into a known state. Since the auto setup operation is different on each instrument, using Auto Setup will break interchangeability. Auto Setup is only recommended for cases where further calls to the instrument are not planned. The Get Information operation retrieves low-level status and information from the instrument. The following figure shows the Get Information operation. The Get Information operation contains the following controls: Get Actual Record Length Specifies a variable or property to which the step assigns the actual number of points the oscilloscope acquires for each channel. After calling Configure you can call the Get Actual Record Length operation to determine the size of the National Instruments Corporation 53 IVI Step Types

54 waveforms that the oscilloscope acquires with the Read or Fetch operations. The value is equal to or greater than the minimum number of points specified by the Min Record Length setting. The oscilloscope might use records of varying sizes depending on the acquisition type. Get Sample Rate Specifies a variable or property to which the step assigns the effective sample rate of the acquired waveform using the current configuration in samples per second. Get Sample Mode Specifies a variable or property to which the step assigns the oscilloscope's current sampling mode. Supported values: Equivalent Time (1) Specifies that the oscilloscope uses equivalent time sampling. Real Time (0) Specifies that the oscilloscope uses real-time sampling. Get Acquisition Status Specifies a variable or property to which the step assigns a value that indicates if an acquisition is in progress or complete or if the status is unknown. This operation does not check the instrument status. Typically, this operation is called only in a sequence of calls to other low-level driver operations (such as Initiate). If the driver cannot query the instrument to determine its state, the operation returns Status Unknown. Supported values: Complete (1) Specifies that the acquisition is complete. In Progress (0) Specifies that the acquisition is in progress. Status Unknown ( 1) Specifies that the driver cannot query the instrument to determine its state or the status is unknown. Get Auto Probe Sense Value Specifies a variable or property to which the step assigns the probe attenuation value that the oscilloscope automatically senses. After you attach the probe to a channel, the probe uses the returned value as the scaling factor for attenuating the input. If the auto probe sense capability is not enabled, this function returns the current manual probe attenuation setting. Use the Channel control to specify the channel name to perform the operation on. The value control specifies the property or variable name the step assigns the returned value to. IVI Step Types 54 ni.com

55 Step Properties Figure 5 shows the step properties for the IVI Scope step type. Figure 5. IVI Scope Step Properties National Instruments Corporation 55 IVI Step Types

56 The IVI Scope step type defines the following step properties in addition to the common custom properties: Step.Result.Reading contains the measurement values for the Read and Fetch operations. This property is an array of container, and the size of the array is equal to the number of channels specified for the Read or Fetch operation. The data type of each element of the array is NI_IviSinglePoint, NI_IviWave or NI_IviWavePair. Step.Logical.Name contains the logical name expression. Step.InstrOperation contains a value that specifies the operation the step is set to perform. Step.SettingSource contains the name of the property or variable where the step loads and stores the settings for the operation. Step.Configuration contains the settings for the Configure operation. The data type of this property is NI_IviDmmConfig. Step.SoftFrontPanel contains the settings for the Show Soft Front Panel operation. The data type of this property is NI_IviSoftFrontPanel. Step.Readings contains the settings for the Read and Fetch operations. The data type of this property is NI_IviScopeReadings. The Channels subproperty is an array of type NI_IviReading. Step.GetInfo contains the settings for the Get Information operation. IVI Fgen Step You use the IVI Fgen step type to instruct function generators to generate predefined waveforms or custom waveforms using arbitrary waveform generators. The step type supports the following operations. Configure Configures the instrument to match the state as specified by the step. Show Soft Front Panel Displays the soft front panel for the instrument. Hide Soft Front Panel Hides the soft front panel for the instrument. Initiate Initiates signal generation if the instrument is idle. Abort Aborts a previously configured output and returns the function generator to the idle state. Send SW Trigger Sends a software trigger command to trigger the instrument. Get Information Retrieves low-level status and information from the instrument. IVI Step Types 56 ni.com

57 Configure The Configure operation configures the instrument to match the instrument state as specified by the step. Basic Tab The following figure shows the Basic tab for the Configure operation. The Basic tab for the Configure operation contains the following controls: Output Mode Determines how the function generator produces waveforms. This setting determines which extension group's functions and settings to use to configure the waveform the function generator produces. Supported values: Standard Function (0) Specifies to use standard function settings to configure the function generator's output signals. Arb Waveform (1) Specifies to use the settings on the Waveforms tab to configure the function generator's output signals. National Instruments Corporation 57 IVI Step Types

58 Sequence (2) Specifies to use the settings on the Sequences tab to configure the function generator's output signals. Ref Check Source Specifies the source of the reference clock. The function generator derives frequencies and sample rates that it uses to generate waveforms from the reference clock. Support values: External (1) Specifies the source of the reference clock to be a signal from an external source. Internal (0) Specifies the source of the reference clock to be a clock signal generated internally. RTSI Clock (101) Specifies the source of the reference clock to be a signal from the RTSI clock source. Arb Sample Rate Specifies the sample rate of the arbitrary waveforms that the function generator produces. The units are samples per second. On function generators with more than one channel, this setting affects all channels. Internal Trigger Rate Specifies the rate at which the function generator's internal trigger source produces a trigger, in triggers per second. The Internal Trigger extension supports function generators that can generate output based on an internally generated trigger signal. You can configure the rate at which internal triggers are generated. This setting affects instrument behavior when the Trigger Source setting is set to Internal Trigger. Auto Stop/Start Automates the stopping and starting of function generation during the Configure operation. When this setting is enabled, Abort is called before a Configure operation takes place, and Initiate is called at the end of a Configure operation. AM Modulation Internal Depth Specifies the extent of modulation the function generator applies to the carrier waveform. This setting affects the behavior of the instrument only when the AM Source setting for a channel is set to AM Internal. The internal depth for modulated waveforms is represented as a percentage. AM Modulation Internal Waveform Specifies the waveform of the internal modulating waveform source for AM. This setting affects the behavior of the instrument only when the AM Source setting for a channel is set to AM Internal. Supported values: DC (6) Selects a DC waveform as the AM internal modulating waveform source. Ramp Down (5) Selects a negative ramp waveform as the AM internal modulating waveform source. IVI Step Types 58 ni.com

59 Ramp Up (4) Selects a positive ramp waveform as the AM internal modulating waveform source. Sine (1) Selects a sinusoid waveform as the AM internal modulating waveform source. Square (2) Selects a square waveform as the AM internal modulating waveform source. Triangle (3) Selects a triangle waveform as the AM internal modulating waveform source. AM Modulation Internal Frequency Specifies the frequency in hertz of the internal modulating waveform source for AM. This setting affects the behavior of the instrument only when the AM Source setting for a channel is set to AM Internal. FM Modulation Internal Deviation Specifies the maximum frequency deviation the function generator applies to the carrier waveform. This setting affects the behavior of the instrument only when the FM Source setting for a channel is set to FM Internal. FM Modulation Internal Waveform Specifies the waveform of the internal modulating waveform source for FM. This setting affects the behavior of the instrument only when the FM Source setting for a channel is set to FM Internal. Supported values: DC (6) Selects a DC waveform as the FM internal modulating waveform source. Ramp Down (5) Selects a negative ramp waveform as the FM internal modulating waveform source. Ramp Up (4) Selects a positive ramp waveform as the FM internal modulating waveform source. Sine (1) Selects a sinusoid waveform as the FM internal modulating waveform source. Square (2) Selects a square waveform as the FM internal modulating waveform source. Triangle (3) Selects a triangle waveform as the FM internal modulating waveform source. FM Modulation Internal Frequency Specifies the frequency in hertz of the internal modulating waveform source for FM. This setting affects the behavior of the instrument only when the FM Source setting for a channel is set to FM Internal. National Instruments Corporation 59 IVI Step Types

60 Channels Tab The following figure shows the Channels tab for the Configure operation. The Channels tab contains a list control with the default channels for the selected logical name. You can use the Add and Remove buttons to add new channels and remove existing channels from the list. You can specify whether the function generator outputs a signal for the channel by enabling the channel using the check box within the list control. If you enable the Preserve Existing Channels checkbox, the step adds to or modifies any existing channels previously configured. When you uncheck the Preserve Existing Channels check box, the step deletes all previously configured channels before configuring the specified channels in the list. The Channels tab for the Configure operation contains the following channel specific controls: Name Specifies the name of the channel. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. IVI Step Types 60 ni.com

61 Output Signal Tab Type Specifies which standard waveform the function generator produces. The valid values vary depending on the Output Mode setting on the Basic tab. When the Output Mode setting is Standard Function, the supported values are: DC (6) Selects a DC waveform as the waveform type. Ramp Down (5) Selects a negative ramp waveform as the waveform type. Ramp Up (4) Selects a positive ramp waveform as the waveform type. Sine (1) Selects a sinusoid waveform as the waveform type. Square (2) Selects a square waveform as the waveform type. Triangle (3) Selects a triangle waveform as the waveform type. When the Output Mode setting is Arb Waveform the Type setting specifies the name of a waveform defined on the Waveforms tab. When the Output Mode setting is Sequence the Type setting specifies the name of a sequence defined on the Sequences tab. Frequency Specifies the frequency of the standard waveform in hertz that the function generator produces, or specifies the rate in hertz at which an entire arbitrary waveform is generated. DC Offset Specifies the DC offset of the standard waveform that the function generator produces, or specifies the offset of the arbitrary waveform in volts that the function generator produces. For standard waveforms, if the Type setting is set to DC, this setting specifies the DC level the function generator produces. The units are volts. Amplitude Specifies the amplitude of the standard waveform that the function generator produces. When the Type setting is set to DC, this setting does not affect signal output. The units are volts. Gain Specifies the gain of the arbitrary waveform that the function generator produces. This value is unitless. National Instruments Corporation 61 IVI Step Types

62 Duty Cycle High Specifies the duty cycle for a square waveform. The value is expressed as a percentage. Start Phase Specifies the start phase of the standard waveform that the function generator produces. When the Type setting is set to DC, this setting does not affect signal output. The units are degrees. Operation Tab Output Impedance Specifies the impedance of the output channel in ohms. Trigger Source Specifies the trigger source for the channel. The function generator produces a signal after it receives a trigger from the source. Supported values: ECL0 (119) Specifies that the function generator waits for a trigger on the ECL 0 line before producing an output signal. ECL1 (120) Specifies that the function generator waits for a trigger on the ECL 1 line before producing an output signal. External (1) Specifies that the function generator waits for a trigger on its external trigger input terminal before producing an output signal. Internal (3) Specifies that the function generator waits for a trigger from its internal trigger source before producing an output signal. PXI Star (131) Specifies that the function generator waits for a trigger on the PXI Star line before producing an output signal. RTSI0 (141) Specifies that the function generator waits for a trigger on the RTSI 0 line before producing an output signal. RTSI1 (142) Specifies that the function generator waits for a trigger on the RTSI 1 line before producing an output signal. RTSI2 (143) Specifies that the function generator waits for a trigger on the RTSI 2 line before producing an output signal. RTSI3 (144) Specifies that the function generator waits for a trigger on the RTSI 3 line before producing an output signal. IVI Step Types 62 ni.com

63 RTSI4 (145) Specifies that the function generator waits for a trigger on the RTSI 4 line before producing an output signal. RTSI5 (146) Specifies that the function generator waits for a trigger on the RTSI 5 line before producing an output signal. RTSI6 (147) Specifies that the function generator waits for a trigger on the RTSI 6 line before producing an output signal. Software (2) Specifies that the function generator waits for the Send Software Trigger operation to execute before producing an output signal. TTL0 (111) Specifies that the function generator waits for a trigger on the TTL 0 line before producing an output signal. TTL1 (112) Specifies that the function generator waits for a trigger on the TTL 1 line before producing an output signal. TTL2 (113) Specifies that the function generator waits for a trigger on the TTL 2 line before producing an output signal. TTL3 (114) Specifies that the function generator waits for a trigger on the TTL 3 line before producing an output signal. TTL4 (115) Specifies that the function generator waits for a trigger on the TTL 4 line before producing an output signal. TTL5 (116) Specifies that the function generator waits for a trigger on the TTL 5 line before producing an output signal. TTL6 (117) Specifies that the function generator waits for a trigger on the TTL 6 line before producing an output signal. TTL7 (118) Specifies that the function generator waits for a trigger on the TTL 7 line before producing an output signal. Operation Mode Specifies how the function generator produces output on a channel. Supported Values: Burst (1) Used when the function generator must produce a burst of waveform cycles based on a trigger condition. National Instruments Corporation 63 IVI Step Types

64 Continuous (0) Used when the function generator must produce output continuously. Burst Count Specifies the number of waveform cycles that the function generator produces after it receives a trigger. The Burst extension group supports function generators capable of generating a discrete number of waveform cycles based on a trigger. The trigger is configured with the Trigger extension group. You can specify the number of waveform cycles to generate when a trigger event occurs. For standard and arbitrary waveforms, a cycle is one period of the waveform. For arbitrary sequences, a cycle is one complete progression through the generation of all iterations of all waveforms in the sequence. This setting affects instrument behavior only when the Operation Mode setting is set to Burst and when the Burst extension is enabled. Modulation Tab AM Modulation Enabled Specifies if the function generator applies amplitude modulation to the carrier waveform. If this setting is enabled, the function generator applies amplitude modulation to the signal that the function generator produces. In order to use this setting, the Modulate AM extension must be enabled. AM Modulation Source Specifies the source of the signal that the function generator uses as the modulating waveform for AM. This setting affects instrument behavior only when the AM Modulation Enabled setting is set to True. In order to use this setting, the Modulate AM extension must be enabled. Supported values: External (1) Specifies a waveform from an external source as the modulating waveform for AM. Internal (0) Specifies an internally generated waveform as the modulating waveform for AM. FM Modulation Enabled Specifies if the function generator applies amplitude modulation to the carrier waveform. If this setting is enabled, the function generator applies amplitude modulation to the signal that the function generator produces. In order to use this setting, the Modulate FM extension must be enabled. FM Modulation Source Specifies the source of the signal that the function generator uses as the modulating waveform for FM. This setting affects instrument behavior only when the FM Modulation Enabled setting is set to True. In order to use this setting, the Modulate FM extension must be enabled. IVI Step Types 64 ni.com

65 Supported values: External (1) Internal (0) Specifies a waveform from an external source as the modulating waveform for FM. Specifies an internally generated waveform as the modulating waveform for FM. Waveforms Tab The following figure shows the Waveforms tab for the Configure operation. The Waveforms tab contains a list control of defined waveforms. You can use the Add and Remove buttons to add new waveforms and remove existing waveforms from the list. If you enable the Preserve Existing Waveforms checkbox, the step adds to or modifies any existing waveforms previously configured. When you uncheck the Preserve Existing Waveforms check box, the step deletes all previously configured waveforms before configuring the specified waveform in the list. National Instruments Corporation 65 IVI Step Types

66 The Waveforms tab for the Configure operation contains the following waveform specific controls: Name Specifies the name of the arbitrary waveform. Source Selects the source of the arbitrary waveform. The waveform source can be a valid ASCII or binary file format, or a waveform returned from an expression that TestStand evaluates. The Filename setting specifies the relative or absolute file path. The Data Source setting specifies the expression that TestStand evaluates. Supported values: Use Data Source Specifies the arbitrary waveform source to be an expression that TestStand evaluates. 2 Byte Integer Specifies the arbitrary waveform source to be a file with 2-byte integer data. 4 Byte Integer Specifies the arbitrary waveform source to be a file with 4-byte integer data. ASCII File Specifies the arbitrary waveform source to be a file with delimited ASCII data. Data Source Specifies the expression that TestStand evaluates when the Source setting is Use Data Source. When TestStand evaluates the expression at run-time, the expression must return an array of number. If the expression specifies a variable or property name, you can use the Load button to import data from a file into the variable or property. The Clear button sets the specified array property to empty. The View button displays the data in the array property in a graph. The default value for the Data Source setting is Step.Configuration.Waveforms, which is an array of waveforms. Each element of the array represents the data for the waveforms specified in the list control. Filename Specifies the source file for the arbitrary waveform when the Source setting is a file. Files can be ASCII files with values that are delimited by a variety of characters including, but not limited to the Carriage return, comma, and semicolon. Additionally, files can be 2-byte or 4-byte integer binary files. Valid binary files contain a different entry every x bytes, where x is 2 or 4 depending on the file. These binary files are not explicitly delimited by anything except space. For instance, if we had a 4-byte integer file containing 5 points, the data might look like this: Address Value 0x0000 0x x0004 0x x0008 0x IVI Step Types 66 ni.com

67 0x000C 0x x0010 0x Auto Normalize Mode Specifies how to normalize an arbitrary waveform, if at all. Normalizing a waveform transforms the waveform so that the normalized points are between the values 1 and 1. If the offset is removed, then the values of the normalized points will span the interval 1 to1. Supported values: No Auto Normalize (0) Selects no automatic normalization of waveform data. Normalize (1) Selects automatic normalization of waveform data to be between 1 and 1. Normalize And Remove Offset (2) Specifies automatic normalization of waveform data, which forces data points to span the interval 1 to1. National Instruments Corporation 67 IVI Step Types

68 Sequences Tab The following figure shows the Sequences tab for the Configure operation. The Sequences tab contains a list control of defined sequences. You can use the Add and Remove buttons to add new sequences and remove existing sequences from the list. If you enable the Preserve Existing Sequences checkbox, the step adds to or modifies any existing sequences previously configured. When you uncheck the Preserve Existing Sequences check box, the step deletes all previously configured sequences before configuring the specified sequence in the list. The Sequences tab for the Configure operation contains the following sequence specific controls: Name Specifies the name of the sequence. Sequence Items Specifies a list of waveforms and how many times to generate each waveform. You can use the Add, Remove, Up and Down buttons to edit the list of waveforms in the list. IVI Step Types 68 ni.com

69 When you select a list item the following controls allow you to end the selected item. Waveform Specifies the name of a waveform defined on the Waveforms tab. Iterations Specifies the number of times that the associated Waveform appears in the sequence for this sequence item. The Iterations setting must be less than or equal to the maximum number of iterations that the function generator allows. Extensions Tab The following figure shows the Extensions tab for the Configure operation. The Extensions tab for the Configure operation contains the following controls: Standard Function Supports extensions for function generators that can produce manufacturer-supplied periodic waveforms. National Instruments Corporation 69 IVI Step Types

70 Arb Waveform Supports extensions for function generators capable of producing user-defined arbitrary waveforms. Arb Sequences Supports extensions for function generators capable of producing sequences of arbitrary waveforms. Arb Frequency Supports extensions for function generators capable of producing arbitrary waveforms and setting the rate at which an entire waveform buffer is generated. Modulate AM Supports extensions for function generators that can apply amplitude modulation to an output signal. Modulate FM Supports extensions for function generators that can apply frequency modulation to an output signal. Burst Supports extensions for function generators capable of generating a discrete number of waveform cycles based on a trigger. Trigger Supports extensions for function generators capable of configuring a trigger. Internal Trigger Supports extensions for function generators that can generate output based on an internally generated trigger signal. Software Trigger Supports extensions for function generators that can generate output based on a software trigger signal. Operation Settings Tab The Operations Settings tab specifies to which property or variable the step saves the operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Initiate Initiates signal generation if the instrument is idle. If the function generator is in the idle state, this operation moves the function generator to the output generation state. If the function generator is already in the output generation state, this operation does nothing. The instrument must be in the generation state after you call the Init operation. Also, you must be able to configure the output of the function generator regardless of whether the function generator is in the idle state or the generation state. You are only required to call the Initiate operation if you abort signal generation by calling the Abort operation. Many function generators constantly generate an output signal, and do not require you to initiate signal generation. If a function generator is always outputting the currently configured signal, this operation does nothing. IVI Step Types 70 ni.com

71 Some function generators require that you abort signal generation prior to configuring the instrument and initiate signal generation after configuring the instrument. The specific drivers for these types of instruments must compensate for this restriction and allow you to configure the instrument without requiring the user to call the Abort and Initiate operations. For these types of instruments, there is often a significant performance increase if you configure the output while the instrument is not generating a signal. You are not required to call the Initiate and Abort operations. If you choose to call these operations, it has no impact on interchangeability. You can choose to use these operations if you want to optimize the application for instruments that exhibit increased performance when output configuration is performed while the instrument is not generating a signal. Abort Aborts a previously configured output and returns the function generator to the idle state. If the function generator is in the output generation state, this operation moves the function generator to the idle state. If the function generator is already in the idle state, the operation does nothing. You can configure the output of the function generator regardless of whether the function generator is in the idle state or the generation state. You are not required to call Abort prior to configuring the output of the function generator. Many function generators constantly generate an output signal and do not require you to abort signal generation prior to configuring the instrument. If a function generator's output cannot be aborted, for example, the function generator cannot stop generating a signal, this operation does nothing. Some function generators require that you abort signal generation prior to configuring the instrument. The specific drivers for these types of instruments must compensate for this restriction and allow you to configure the instrument without requiring you to call the Abort operation. For these types of instruments, there is often a significant performance increase if you configure the output while the instrument is not generating a signal. You are not required to call the Initiate and Abort operations. If you choose to call these operations in an application program, it has no impact on interchangeability. You can choose to use these operations if you want to optimize the application for instruments that exhibit increased performance when output configuration is performed while the instrument is not generating a signal. National Instruments Corporation 71 IVI Step Types

72 Send Software Trigger Sends a software trigger command to trigger the instrument. This operation sends a software trigger when a Trigger Source setting is set to Software Trigger. To use this operation, the Software Trigger extension must be enabled. Get Information The Get Information operation retrieves low-level status and information from the instrument. The following figure shows the Get Information operation. IVI Step Types 72 ni.com

73 The Get Information operation contains the following controls: Get Max Num Waveforms Specifies a variable or property to which the step assigns the maximum number of arbitrary waveforms that the function generator allows. Get Max Waveform Size Specifies a variable or property to which the step assigns the maximum number of points the function generator allows in an arbitrary waveform. Get Min Waveform Size Specifies a variable or property to which the step assigns the minimum number of points the function generator allows in an arbitrary waveform. Get Waveform Quantum Specifies a variable or property to which the step assigns the quantum value that the function generator allows. Get Max Loop Count Specifies a variable or property to which the step assigns the maximum number of times the function generator can repeat an arbitrary waveform in a sequence. Get Max Num Sequences Specifies a variable or property to which the step assigns the maximum number of sequences that the function generator allows. Get Max Sequence Length Specifies a variable or property to which the step assigns the maximum number of arbitrary waveforms the function generator allows in a sequence. Get Min Sequence Length Specifies a variable or property to which the step assigns the minimum number of arbitrary waveforms the function generator allows in a sequence. National Instruments Corporation 73 IVI Step Types

74 Step Properties Figure 6 shows the step properties for the IVI Fgen step type. Figure 6. IVI Fgen Step Properties IVI Step Types 74 ni.com

75 IVI DC Power Supply Step The IVI Fgen step type defines the following step properties in addition to the common custom properties: Step.Logical.Name contains the logical name expression. Step.InstrOperation contains a value that specifies the operation the step is set to perform. Step.SettingSource contains the name of the property or variable where the step loads and stores the settings for the operation. Step.Configuration contains the settings for the Configure operation. The data type of this property is NI_IviFgenConfig. Step.SoftFrontPanel contains the settings for the Show Soft Front Panel operation. The data type of this property is NI_IviSoftFrontPanel. Step.GetInfo contains the settings for the Get Information operation. You use the IVI DC Power Supply step type to instruct power supplies to control the output voltages and currents, and measure output values at the output terminals. The step type supports the following operations. Configure Configures the instrument to match the state as specified by the step. Show Soft Front Panel Displays the soft front panel for the instrument. Hide Soft Front Panel Hides the soft front panel for the instrument. Measure Takes a measurement on the output signal and returns the measured value. Initiate Makes the power supply wait for a trigger. Abort Cancels the wait for a trigger. Send SW Trigger Sends a software trigger command to trigger the instrument. Get Information Retrieves low-level status and information from the instrument. National Instruments Corporation 75 IVI Step Types

76 Configure The Configure operation configures the instrument to match the instrument state as specified by the step. Channels Tab The following figure shows the Channels tab for the Configure operation. The Channels tab contains a list control with the default channels for the selected logical name. You can use the Add and Remove buttons to add new channels and remove existing channels from the list. You can specify whether the power supply outputs a signal for the channel by enabling the channel using the check box within the list control. If you enable the Preserve Existing Channels checkbox, the step adds to or modifies any existing channels previously configured. When you uncheck the Preserve Existing Channels check box, the step deletes all previously configured channels before configuring the specified channels in the list. IVI Step Types 76 ni.com

77 The Channels tab for the Configure operation contains the following channel specific controls: Name Specifies the name of the channel. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. Voltage Level Specifies the voltage level in volts that the DC power supply attempts to generate. Output Range Mode Specifies how to configure the power supply's output range on a channel. Supported values: Automatic ( 1) Chooses the Voltage Level setting to be used to configure the range of the instrument. Use Current Range (0) Chooses the Current Range setting to be used to configure the range of the instrument. Use Voltage Range (1) Chooses the Voltage Range setting to be used to configure the range of the instrument. Voltage Range Specifies the maximum voltage value of the instrument if Output Range Mode is set to Use Voltage Range. Setting a voltage range can invalidate a previously configured current range. Current Range Specifies the maximum current value of the instrument if Output Range Mode is set to Use Current Range. Setting a current range can invalidate a previously configured voltage range. Current Limit Behavior Specifies the behavior of the power supply when the output current is equal to or greater than the value of the Current Limit setting. Supported values: Current Regulate (0) Indicates the output voltage restriction. The power supply restricts the output voltage so that the output current is not greater than the value of the Current Limit setting. Current Trip (1) Indicates the disabling output voltage. The power supply disables the output when the output current is equal to or greater than the value of the Current Limit setting. Current Limit Specifies the output current limit in amperes. The value of the Current Limit Behavior setting determines the behavior of the power supply when the output current is equal to or greater than the value of the Current Limit setting. National Instruments Corporation 77 IVI Step Types

78 OVP Enabled Specifies if the power supply provides Overvoltage Protection. If this property is set to True, the power supply disables the output when the output voltage is greater than or equal to the value of the OVP Limit setting. OVP Limit Specifies the maximum voltage in volts that the power supply allows. If the OVP Enabled setting is set to True, the power supply disables the output when the output voltage is greater than or equal to the value of the OVP Limit setting. If the OVP Enabled setting is set to False, the OVP Limit setting does not affect the behavior of the instrument. Trigger Source Specifies the trigger source. After you call Initiate, the power supply waits for a trigger event from the source you specify with the Trigger Source setting. After a trigger event occurs, the power supply changes the voltage level to the value of the Triggered Voltage Level setting and the current limit to the value of the Triggered Current Limit setting. Supported values: Software (2) Indicates that the power supply waits for the Send Software Trigger operation to execute before changing the output signal. ECL0 (11) Indicates that the power supply waits for a trigger on the ECL 0 line before changing the output signal. ECL1 (12) Indicates that the power supply waits for a trigger on the ECL 1 line before changing the output signal. External (1) Indicates that the power supply waits for an external trigger before changing the output signal. Immediate (0) Indicates that the power supply does not wait for a trigger before changing the output signal. PXI Star (13) Indicates that the power supply waits for a trigger on the PXI STAR line before changing the output signal. RTSI0 (14) Indicates that the power supply waits for a trigger on the RTSI 0 line before changing the output signal. RTSI1 (15) Indicates that the power supply waits for a trigger on the RTSI 1 line before changing the output signal. IVI Step Types 78 ni.com

79 RTSI2 (16) Indicates that the power supply waits for a trigger on the RTSI 2 line before changing the output signal. RTSI3 (17) Indicates that the power supply waits for a trigger on the RTSI 3 line before changing the output signal. RTSI4 (18) Indicates that the power supply waits for a trigger on the RTSI 4 line before changing the output signal. RTSI5 (19) Indicates that the power supply waits for a trigger on the RTSI 5 line before changing the output signal. RTSI6 (20) Indicates that the power supply waits for a trigger on the RTSI 6 line before changing the output signal. TTL0 (3) Indicates that the power supply waits for a trigger on the TTL 0 line before changing the output signal. TTL1 (4) Indicates that the power supply waits for a trigger on the TTL 1 line before changing the output signal. TTL2 (5) Indicates that the power supply waits for a trigger on the TTL 2 line before changing the output signal. TTL3 (6) Indicates that the power supply waits for a trigger on the TTL 3 line before changing the output signal. TTL4 (7) Indicates that the power supply waits for a trigger on the TTL 4 line before changing the output signal. TTL5 (8) Indicates that the power supply waits for a trigger on the TTL 5 line before changing the output signal. TTL6 (9) Indicates that the power supply waits for a trigger on the TTL 6 line before changing the output signal. TTL7 (10) Indicates that the power supply waits for a trigger on the TTL 7 line before changing the output signal. Triggered Current Limit Specifies the value in amperes to which the power supply sets the current limit after a trigger event occurs. After you call Initiate, the power supply waits for a trigger event from the source you specify with the Trigger Source setting. After a trigger National Instruments Corporation 79 IVI Step Types

80 event occurs, the power supply sets the current limit to the value of the Triggered Current Limit setting. After a trigger occurs, the value of the Current Limit setting reflects the new value to which the current limit has been set. Triggered Voltage Level Specifies the value in volts to which the power supply sets the voltage level after a trigger event occurs. After you call Initiate, the power supply waits for a trigger event from the source you specify with the Trigger Source setting. After a trigger event occurs, the power supply sets the voltage level to the value of the Triggered Voltage Level setting. After a trigger occurs, the value of the Voltage Level setting reflects the new value to which the voltage level has been set. Extensions Tab The following figure shows the Extensions tab for the Configure operation. IVI Step Types 80 ni.com

81 The Extensions tab for the Configure operation contains the following controls: Trigger - Supports extensions for DC power supplies that can change the voltage at the output terminals based on a Trigger event. Software Trigger Supports extensions for DC power supplies that can change the voltage at the output terminals based on the Software Trigger operation. Measurement Supports extensions for DC power supplies that can make measurements, such as voltage and current measurements, at the output terminals. Operation Settings Tab The Operations Settings tab specifies to which property or variable the step saves the operation settings to when closing the edit dialog, and reloads the operation settings when displaying the edit dialog. Measure The Measure operation takes a measurement on the output signal and returns the measured value. The Measure operation causes a voltage and/or current measurement to be taken at the output terminals. The Measurement extension must be enabled before using this operation. The returned value is the actual voltage or current reading. National Instruments Corporation 81 IVI Step Types

82 Channels Tab The following figure shows the Measure operation. The Channels tab contains a list control with the default channels for the selected logical name. You can use the Add and Remove buttons to add new channels and remove existing channels from the list. You can specify whether the power supply measures the output for the channel by enabling the channel using the check box within the list control. The Channels tab for the Measure operation contains the following channel specific controls: Name Specifies the name of the channel to read. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. IVI Step Types 82 ni.com

83 Measurement Type Specifies the type of data to retrieve from the oscilloscope. Supported values: Current (0) Indicates that the current is measured at the output terminals. Voltage (1) Indicates that the voltage is measured at the output terminals. Measurement Destination Specifies a variable or property to which the step assigns the measurement value. The data type of the variable or property must be Number or NI_IviSinglePoint. The default configuration for the step specifies Step.Result.Reading as the destination. This property is an array of container, and the size of the array is equal to the number of channels specified for the Measure operation. When you edit the step, the step automatically resized the array. If you do not specify Step.Result.Reading as the destination, TestStand still copies the measurement value to the Data subproperty in each array element at runtime. Initiate Abort Makes the power supply wait for a trigger. If the power supply is not currently waiting for a trigger, this operation causes the power supply to wait for a trigger. If the power supply is already waiting for a trigger, this operation does nothing. Cancels the wait for a trigger. If the power supply is waiting for a trigger to change the output signal, this operation returns the power supply to the ignore triggers state. Reset Output Protection If the power supply is not waiting for a trigger, this operation does nothing. Send Software Trigger Updates the voltage level and current limit when a DC power supply is in the wait for trigger state. This operation sends a software trigger when the Trigger Source setting is set to Software. After the trigger occurs, the voltage level and current limit are updated with the values of triggered current limit and the triggered voltage level. To use this operation, the Software Trigger extension must be enabled. Resets the power supply's output protection on a specific channel after an overvoltage or overcurrent condition occurs. An overvoltage condition occurs when the output voltage is equal to or greater than the value of the National Instruments Corporation 83 IVI Step Types

84 OVP Limit setting and the OVP Enabled setting is set to True. An overcurrent condition occurs when the output current is equal to or greater than the value of the Current Limit setting and the Current Limit Behavior setting is set to Current Trip. When either an overvoltage condition or an overcurrent condition occurs, the output protection of the power supply disables the output. Once the output protection is reset, the power supply resumes generating a power signal. You can use the Query Output State operation on the Get Information tab to determine if the power supply is in an overvoltage or overcurrent state. All specific drivers might not support the Reset Output Protection operation. Get Information The Get Information operation retrieves low-level status and information from the instrument. The following figure shows the Get Information operation. IVI Step Types 84 ni.com

85 The Get Information operation contains the following controls: Channel Name Specifies the name of the channel to operate on. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. Query Max Current Limit Query the maximum programmable current limit that the power supply accepts for a particular voltage level on a channel. Voltage Level Specifies the voltage level for which you want to find the maximum programmable current limit. Max Current Limit Specifies a variable or property to which the step assigns the maximum programmable current limit. Query Max Current Limit Query the maximum programmable voltage level that the power supply accepts for a particular current limit on a channel. Voltage Level Specifies the current limit for which you want to find the maximum programmable voltage level. Max Voltage Level Specifies a variable or property to which the step assigns the maximum voltage level. Query Output State Query the value of a specified DC power supply output state. Output State Specifies the output state to query. Supported values: Constant Current (1) Determines if an instrument is in constant current mode. A constant current condition occurs when the output current is equal to the value of the Current Limit setting and the Current Limit Behavior setting is set to Current Regulate. Constant Voltage (0) Determines if an instrument is in constant voltage mode. A constant voltage condition occurs when the output voltage is equal to the value of the Voltage Level setting and the current is less than or equal to the value of the Current Limit setting. Over Current (3) Determines if an overcurrent condition exists in the instrument. An overcurrent condition occurs when the output current is equal to or greater than the value of the Current Limit setting and the Current Limit Behavior property is set to Current Trip. Over Voltage (2) Determines if an overvoltage condition exists in the instrument. An overvoltage National Instruments Corporation 85 IVI Step Types

86 condition occurs when the output voltage is equal to or greater than the value of the OVP Limit setting and the OVP Enabled setting is set to True. Unregulated (4) Determines if an unregulated condition exists in the instrument. An unregulated condition occurs when the output voltage is less than the value of the Voltage Level setting and the current is less than the value of the Current Limit setting. Value Specifies a Boolean variable or property to which the step assigns the output state. When either an overvoltage condition or an overcurrent condition occurs, the power supply's output protection disables the output. If the power supply is in an overvoltage or overcurrent state, it does not produce power until the output protection is reset. The Reset Output Protection operation resets the output Protection. Once the output protection is reset, the power supply resumes generating a power signal. Some drivers might not support the querying of all the output states. Reset Output Protection might not be supported with all drivers. IVI Step Types 86 ni.com

87 Step Properties Figure 7 shows the step properties for the IVI DC Power Supply step type. Figure 7. IVI DC Power Supply Step Properties National Instruments Corporation 87 IVI Step Types

88 The IVI DC Power Supply step type defines the following step properties in addition to the common custom properties: Step.Result.Reading contains the measurement values for the Measure operation. The property data type is an array of NI_IviSinglePoint. Step.Logical.Name contains the logical name expression. Step.InstrOperation contains a value that specifies the operation the step is set to perform. Step.SettingSource contains the name of the property or variable where the step loads and stores the settings for the operation. Step.SoftFrontPanel contains the settings for the Show Soft Front Panel operation. The data type of this property is NI_IviSoftFrontPanel. Step.Readings contains the settings for the Measure operation. Step.GetInfo contains the settings for the Get Information operation. IVI Tools Step You can use the IVI Tools step type to perform low-level operations on an instrument. The step type supports the following operations: Get Session Info Retrieve low-level session references and API class handles to the IVI instrument. Show Soft Front Panel Displays the soft front panel for the tool. Hide Soft Front Panel Hides the soft front panel for the tool. Init Initializes the driver or I/O resource for the session. Close Closes (uninitializes) the IVI session. Reset Places the instrument in a known state. Self Test Causes the instrument to perform a self-test. Revision Query Queries the instrument driver and instrument for revision information. Error Query Returns instrument-specific error information. Get Error Info Returns error information for the last IVI error for a session. Set/Get/Check Attributes Allows you to set, query or verify the value of attributes. Get Session Info The Get Session Info operation allows you to get the low-level session manager instrument session, and the API class handles and references to the IVI instrument. IVI Step Types 88 ni.com

89 The following figure shows the Get Session Info operation. The Get Session Info operation contains the following controls: Session Manager Reference Specifies a variable or property to which the step assigns a COM pointer to the InstrSession object that the Session Manager creates for the specified logical name. You can use an InstrSession object to obtain an instrument API handle or reference. C Driver Handle Specifies a variable or property to which the step assigns the C-based class API handle for the specified logical name. You use a class handle to control an instrument via an IVI class driver. COM Driver Reference Specifies a variable or property to which the step assigns the COM pointer to the class API object for the specified logical name. You use a class reference to control an instrument via an IVI class COM interface. ActiveX Control Reference Specifies a variable or property to which the step assigns the COM pointer to the Measurment Studio for Visual Basic ActiveX control for the class specified by the logical name. You use a control reference to interact with the instrument via the Measurment Studio COM interface. National Instruments Corporation 89 IVI Step Types

90 Note For the current version of IVI, do not pass an instrument handle between operating system processes because instrument driver handles you obtain in one process do not functioninanyotherprocess. Init The Init operation initializes the driver or I/O resource for the session. Normally a session automatically initializes an instrument session when an execution runs an IVI step. The following figure shows the Init operation. The Init operation contains the following controls: Perform Id Query Specifies whether the init operation performs an identification query on the instrument. Reset Specifies whether the init operation also resets the instrument. Aresetoperationtoplacetheinstrumentinaknownstate.InanIEEE instrument, the Reset operation sends the command string *RST to the instrument. Reset also sends the default setup IVI Step Types 90 ni.com

91 commands to the instrument to configure settings for the proper operation of the instrument driver. Additional Initialization Options Specifies additional options separated by comma that are supported by IVI. Some examples include: Simulate=1 RangeCheck=1 QueryInstrStatus=1 Cache=1 RecordCoercions=1 InterchangeCheck=1 UseSpecificSimulation=1 ReInitialization Action Specifies the behavior of the Init operation if Init is being called on a previously opened instrument session. Supported values: Noop (0) Specifies that if there is an active session to the current logical name, calling Init have no effect. Close and Init (1) Specifies that if there is an active session to the current logical name, that session is closed and a new one is opened. Raise Error (2) Specifies that if there is an active session to the current logical name, calling Init causes an error. Close Reset Self Test The Close operation closes (uninitializes) the IVI session for the specified logical name. Normally, the instrument session for a logical name automatically closes when the last execution closes that ran an IVI step. The Reset operation places the instrument in a known state. In an IEEE instrument, the Reset operation sends the command string *RST to the instrument. Reset also sends the default setup commands to the instrument to configure settings for the proper operation of the instrument driver. The Self Test operation causes the instrument to perform a self-test. The operation waits for the instrument to complete the test. It then queries the instrument for the results and returns them. National Instruments Corporation 91 IVI Step Types

92 The following figure shows the Self Test operation. The Self Test operation contains the following controls: Test Result Specifies a variable or property to which the step assigns the numeric result from the self-test. Returns 0 for no error (test passed). Test Message Specifies a variable or property to which the step assigns the self-test status message. IVI Step Types 92 ni.com

93 Revision Query The Revision Query operation queries the instrument driver and instrument for current revisions. The operation returns the revision of the instrument driver and the revision of the firmware for the instrument you are using. The following figure shows the Revision Query operation. The Revision Query operation contains the following controls: Driver Revision Specifies a variable or property to which the step assigns the revision information for the instrument driver. Instrument Revision Specifies a variable or property to which the step assigns the revision information for the instrument firmware. Error Query The Error Query operation queries the instrument and returns the instrument-specific error information. You call use this operation after another operation in the instrument driver returns the IVI_ERROR_INSTR_SPECIFIC error code. The driver returns IVI_ERROR_INSTR_SPECIFIC when the instrument sstatusregister National Instruments Corporation 93 IVI Step Types

94 indicates that the instrument s error queue is not empty. The Error Query operation extracts the first error out of the instrument s error queue. For instruments that have status registers but no error queue, the driver simulates an error queue in software. The following figure shows the Error Query operation. The Error Query operation contains the following controls: Error Code Specifies a variable or property to which the step assigns the error code returned from the instrument error query. Error Message Specifies a variable or property to which the step assigns the readable description of the error code. IVI Step Types 94 ni.com

95 Get Error Info The Get Error Info operation returns error information for the last IVI error for a given IVI session. The operation retrieves and then clears the error information for the instrument session. The error information includes a primary error code, a secondary error code, and an error elaboration string. The error information is the same as the values held in the following IVI attributes: IVI_ATTR_PRIMARY_ERROR IVI_ATTR_SECONDARY_ERROR IVI_ATTR_ERROR_ELABORATION The following figure shows the Get Error Info operation. The Error Query operation contains the following controls: Primary Error Code Specifies a variable or property to which the step assigns primary error code for the session or execution thread. A value of VI_SUCCESS (0) indicates that no error occurred. A positive value indicates a warning. A negative value indicates an error. National Instruments Corporation 95 IVI Step Types

96 Set/Get/Check Attributes Secondary Error Code Specifies a variable or property to which the step assigns the secondary error code for the session or execution thread. If the primary error code is a nonzero value, the secondary error code can further describe the error or warning condition. A value of VI_SUCCESS (0) indicates no further description. Error Elaboration Specifies a variable or property to which the step assigns the error elaboration string for the session or execution thread. If the primary error code is a nonzero value, the elaboration string can further describe the error or warning condition. The Set/Get/Check Attributes operation allows you to set the value of attributes, query the value of attributes, and verify that a values you specify for attributes are valid. The following figure shows the Set/Get/Check Attributes operation. IVI Step Types 96 ni.com

97 The list control contains the attributes you are operating on. You can use the Add and Remove buttons to add new attributes and remove existing attributes from the list. The Attribute section on the dialog box for the operation contains the following attribute specific controls: Operation Specifies whether the step gets the value, set the value or verifies the value of the attribute. Id Or Name Specifies the index of the IVI attribute or the name of the IVI attribute. Channel Name Specifies the name of the channel to operate on. The channel name must be a valid virtual channel name as defined by the IVI configuration for the logical name being used. This setting only applies to attributes of channels. Value For Set and Check operations, the control specifies the attribute value to assign or verify. For Get operations, the control specifies a variable or property to which the step assigns the returned value. National Instruments Corporation 97 IVI Step Types

98 Step Properties Figure 8 shows the step properties for the IVI Tools step type. Figure 8. IVI Tools Step Property The IVI Tools step type defines the following step properties in addition to the common custom properties: Step.Logical.Name contains the logical name expression. Step.InstrOperation contains a value that specifies the operation the step is set to perform. Step.SettingSource contains the name of the property or variable where the step loads and stores the settings for the operation. Step.SoftFrontPanel contains the settings for the Show Soft Front Panel operation. The data type of this property is NI_IviSoftFrontPanel. Step.Init contains the settings for the Init operation. Step.SelfTest contains the settings for the Self Test operation. Step.SessionInfo contains the settings for the Get Session Info operation. IVI Step Types 98 ni.com