HT101V Reference Manual Overview The HT101V from Ag-Tester is our handheld tester designed to diagnose valve components on agricultural machinery. Valves tested include: 1- Boom Control Valves 2- Servo Rate Control Valves 3- PWM Control Valves The top section of the HT101V is the meter. The user can make measurements including Voltage, Frequency and Resistance. The lower part of the HT101V is the diagnostic and valve control center. When used with the In-Line, Tester- Tee harness, the HT101V will monitor the supply and control voltages being provided by the display. Test terminals are built into the HT101V to allow metering connections to be made without disturbing the connectors and cables associated with the control console. Valves can be fully tested, in-line, independently from the display. When used with the Stand- Alone, Tester Tee harness, any valve can be fully tested on the bench. The back panel provides connections for inputs and charging along with the magnetic RAM mount. Heat Sink- Absorbs heat generated while driving PWM Valves. RAM Mount Attaches here with Magnet. Input Connection- Connect the Tester Tee Harness here for In-Line or Stand-alone tests. Charger Connector
Meter functions The Meter Function switch selects the type of measurement being made. Select from the following: VOLTS 0 to 20 Volts DC. with automatic polarity FREQ Frequency 0 to 1000 HZ CONT Continuity or Ohms 0 to 2000 The Connected Point switch selects the testing method. There are 4 options. TEST, PATCH, COAX, or BATT CHECK When dialed to TEST the standard meter test leads are installed in the RED outlined lead jacks. The meter can then be used as you would a standard test meter. Dial to PATCH to use the Patch Cables connecting at the Green outlined lead jacks. This allows an easy connection to the wires connecting the Display console to the control valve. Setting the CONNECTED POINT to COAX allows for an easy connection to a TNC type coax connector. Most GPS receivers send 5 volts to the antenna to operate an internal amplifier. Disconnect the cable from the gps antenna and re-install at COAX on the HT101V. When VOLTS is selected you should see 5 to 12 volts on the meter indicating a good connection from the antenna connection to the gps receiver. When dialed to BATT CHECK and VOLTS the meter indicates the current internal battery voltage. Fully charged it may read as high as 13.5 VDC. The tester will function properly until below 12 volts. No wire connection is required. Battery can be checked while performing other tests.
Diagnostic Functionality and Valve Testing Functions The Tester Function Switch located at the lower right. When dialed to any position other than OFF, the meter functions are all available. Set to MONITOR to make tests on the control cable coming from the display to the control valve. When connected for In-Line testing there are as many as four (4) possible connections. A four wire valve will have a ground, main power, and two control lines. The HT101V makes these connections available as Test Jacks and any voltage present on a line will light the associated LED. Test Jacks and LEDs are colorized to indicate: RED = Supply Voltage from Display Yellow= Open Valve command voltage from display Green= Close Valve command voltage from display Black= Ground A two wire control valve will only use the Yellow/ Green, open- close command voltages. TEST SERVO and TEST PWM are colorized matching drive controls with the correct valve type. TEST SERVO is in GREEN while TEST PWM is in Yellow. There are times when a servo valve is actually controlled with PWM pulses. Follow instructions carefully. The DRIVE controls are at minimum when counter clockwise and maximum at clockwise. The SERVO TEST switch is a center off momentary contact toggle switch. Holding the switch to the left drives the valve open and lights the YELLOW LED. Holding the switch to the right drives the valve closed and lights the GREEN LED. With the DRIVE CONTROL fully clockwise maximum power is sent to the valve. The speed of the valve operation is determined by the DRIVE CONTROL. PWM TEST uses the DRIVE CONTROL to set the width of the drive pulses. The TEST switch is a momentary contact switch. When testing PWM type valves always start with the drive control fully counter-clockwise. Press TEST and slowly increase the PWM Drive. PWM Valves are two wire valves. There are four wire valves that respond to PWM pulses for drive control. In those cases, the SERVO TEST switch is used to control the direction of movement and the PWM DRIVE CONTROL sets the speed of valve operation. Keep both drive controls at minimum. Then only use ONE to set the valve speed and complete the tests.
Types of valves to be tested The HT101V is designed to be compatible with Any valve on Any machine. Specific valve types require specific control voltages to operate correctly. The following explains the differences. It is important to know what type of valve you re dealing with to insure the best level of diagnosis. Solenoid Valves- A simple On/ Off valve that uses a charged coil to engage the valve. 12 Volts present activates the coil and operates the valve. Removing 12 volts dis-engages the valve. Polarity normally doesn t matter. Motorized Ball Valves- These valves operate at full speed all the time. They many times will have three wires. Plus 12 volts constant, Ground or minus 12 volts, and a signal line. The signal wire uses 12 volts to open the valve and lack of 12 volts closes the valve. There are 4 wire motorized ball valves. Here 12 volts and ground are supplied constantly. The other two wires signal open/ close by supplying 12 volts but reversing the polarity to signal open/ close. Servo Control Valves- Servo valves are motorized valves designed to provide smooth control of open and close operation. The speed of the valve is controlled by varying the voltage or drive to the motor. The motor operates at full speed with 12 volts applied but will typically move slowly with as little as 3 volts or less. The polarity of the applied control voltage controls the direction of operation. Control systems constantly change the control voltage to affect the movement speed or response. As an example; a spray controller will run the control voltage to maximum when big changes are required, then drastically drop the voltage as the target rate is reached. Fine tuning is performed at minimum operating voltage. Servo valves may work perfectly at full voltage, drive but not move at all at low control voltages. PWM Valves- PWM means pulse width modulated. Modulate means, to change. PWM valves are closed when there is no signal. The valve then begins to open as pulses are applied, so the valve is effectively opening and closing with each pulse. The control signal voltage is turning on, then off, at a rate of about 100 times per second or 100Hz. Applying a constant 12 volts to the PWM valve coil will run the valve at full speed. An oscilloscope image shows the pulse width changing. The percentage of time ON is called the DUTY CYCLE. ZERO VOLTS- 11 VOLTS- Drive Voltage changes from Zero to Eleven Volts, 100 times per second ON about 25 percent of the time- ON about 50 percent of the time ON about 70 percent of the time PWM Valves are two wire valves and look a lot like solenoid valves. RAVEN PWM valves reach full output at 55% drive. DITHERING SERVO VALVES- 4 WIRE- Some servo control valves respond to PWM commands. The speed of the valve is controlled by the pulse width of the drive signal rather than a varying drive voltage to control valve speed. They have 4 wires with a constant Ground and Plus 12 Volts supplied. The control signal is pulse width modulated. Some would call these valves, current controlled. RAVEN 4 wire FAST VALVES and DICKEY-john control valves are this type.
Using the HT101V- Stand-Alone Testing Stand-alone testing is used as a method of testing and evaluating or bench testing a control valve independent of the display. The HT101V allows for full testing of any valve. Use the Tester Tee Harness and adapters to fit best with the valves you re testing. Here we re using the TT-AE27996 Stand-alone RAVEN harness. Boom control valves are three wire control valves that always work at full speed. Set the Function switch to TEST SERVO. Hold the SERVO TEST Switch to the LEFT, OPEN while increasing the SERVO DRIVE. The required drive is around seven volts. Use the PATCH cables if you want to monitor the required voltage with the plus lead at YELLOW and the meter ground at GND on the test jacks. WHEN USING THE SERVO DRIVE CONTROL TURN THE PWM DRIVE TO MINIMUM SERVO Valves are motorized valves that are designed to be finely adjustable. The motors run at full speed with 12 volts applied. A minimum of two to three volts is applied to fine tune the valve position. When failing, these valves may run perfectly at full speed, yet not at all with lower drive voltages. The HT101V allow you to fully test the operational range. Set the Function switch to TEST SERVO. Set the SERVO DRIVE control to fully clockwise. See if the valve runs with FULL DRIVE using the SERVO TEST switch, LEFT to open and RIGHT to close. If the valve runs at FULL DRIVE, check it with MINIMUM DRIVE. Use the SERVO DRIVE CONTROL and monitor the drive voltage at the yellow and black test jacks. Good valves will run with as little as 3 or 4 volts of drive. WHEN USING THE SERVO DRIVE CONTROL, SET THE PWM DRIVE TO MINIMUM WHEN USING THE PWM DRIVE CONTROL, SET THE SERVO DRIVE TO MINIMUM PWM Valves are two wire valves. Set the function switch to TEST PWM. Use the momentary contact PWM TEST switch to activate the drive. Always start the test with the PWM DRIVE control set to MINIMUM. Push the TEST button and increase the drive. With standalone tests there is not much to see. You can hear the valve coil in most cases. The sound increases in pitch with increased drive. If the valve is installed in a hydraulic circuit, you ll see the hydraulic motor speed up as the drive is increased. Control occurs at about 50 percent. There is no reason to go to full drive clockwise position.
Some Servo Valves respond to pulses from a PWM Drive more accurately than a standard variable voltage drive. The HT101V is wired so that the PWM Drive can be used with a Servo Valve. Dial the function switch to TEST SERVO. Be sure the SERVO DRIVE control is set to MINIMUM, COUNTER CLOCKWISE. Use the SREVO CONTROL switch holding left to open and right to close. The PWM DRIVE vontrol then controls the pulsewidth, thusly the valve speed. This RAVEN FAST VALVE responds nicely with both standard servo drive or pwm drive. 4 WIRE Dithering valves like the RAVEN FAST- 4 wire valve will test as above. A true PWM type servo will not control with standard SERVO DRIVE. You will find this type of servo will Run at Full Speed with any level of standard voltage control drive. In-Line Testing Use In-Line Tester Tee Harness- TT-AE27995 for RAVEN The In-Line Tester Tee harness is installed between the valve being tested and the cable feeding the valve from the controller display. TO VALVE TO DISPLAY Once installed, the HT101V will display the supply voltages and signals provided by the display. The four test jacks are connected to the wires controlling the valve coming from the display. LED light up indicating voltage present on the individual wires. Four wire valves use: Red= Supply Plus Power, Yellow= Valve Open, Green= Valve Close, and Black= Supply Negative or Ground. Three wire valves use: Red = Supply Plus Power, Yellow= Valve open, Black= Ground or supply negative. Two wire servo valves use: Yellow and Green. Valve open is Yellow= plus and Green= negative. The voltage reverses to control the motor open/ closed. No power applied stops the valve. Two wire PWM valves use Yellow and Green. Yellow is the signal drive and green is ground.