HAEHNE. Digital Strain Gauge Amplifier DMA2. Adjustment Instructions. Content

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Adjustment Instructions Digital Strain Gauge Amplifier DMA2 Content...Page Operating Mode... 2 Adjustment Modes Zero adjust calibration... 2 Amplification parameter defined by a value (gain).

.. 4 Filter type of the current output... 4 Output signal range... 5 Display value... 5 Adjustement Of The Parameters Automatic zero point adjustment... 6 Manual zero point adjustment.

1 Adjustment Instructions Digital Strain Gauge Amplifier DMA2 Content...Page Operating Mode... 2 Adjustment Modes Zero adjust calibration... 2 Amplification parameter defined by a value (gain)... 2 Amplification adjustment with calibration weights... 2 Connection / Wiring... 3 Operation Preparation... 4 Adjustment mode... 4 PreAdjustments / Operationg Modes Display intensity... 4 Filter type of the current output... 4 Output signal range... 5 Display value... 5 Adjustement Of The Parameters Automatic zero point adjustment... 6 Manual zero point adjustment... 6 Entering amplification as gain value... 6 Amplification adjustment with calibration weights... 7 Peak value display... 8 Fault display during operation... 8 Technical modifications reserved

2 The selected sequence of the adjustment steps is based on experience in practice situations. Other sequences of adjustment steps are certainly possible. Operating Mode The DMA2 is a strain gauge amplifier processes sensor signals in the analog mode. The parameter values, however, are digitally adjusted. LEDs indicate the operating status. The digital display shows the parameter value respectively the output signal. Adjustment Modes Zero adjust calibration either automatically by key operation (details: see page 6) or manual: moving the zero point by the amount of the web weight on the measuring/idler roll The second possibility is useful if e.g. the web tension control system is preloaded with the defined web weight either while in operation or at standstill. Another application can be e.g. a silo which cannot be completely emptied and has a certain amount of weight remaining. Amplification parameter defined by a value (gain) In this case the gain is calculated and correspondingly adjusted Example Sensor data: nominal rating 1,5 m V/V bridge supply voltage: 10 V (the output signal is therefore 15 mv = V at nominal force) Amplifier output: 10 V at nominal web tension 0 V at zero web tension Gain = 10V 0,015 V = 666,66 666,7 If the sensor is operating below its nominal force then the amplification must be increased. Example The maximum sensor load is only 75% of nominal force. The output signal is therefore only: 75 % 15 mv = 11,25 mv 100 % this leads to: 10V Gain = = 888,88 888,9 0,01125 V Amplification adjustment with calibration weights In this operating modes the web tension measurement equipment is loaded with calibration weights and the amplification is adjusted accordingly. This is the more realistic but more cumbersome method. page 2

3 Sensor B does not exist in case of singlesided measurement V 1 V 2 Output signal of full bridge strain gauge Direct voltage output V 3 Dampened voltage output different connection in case of explosion proof applications V 4 V 5 Excitation voltage to the full bridge strain gauge in the sensors Supply voltage 24 V DC I 1 Current output (option C and N) field field PE terminal green white brown yellow PE terminal green white brown yellow The four terminal blocks with five terminals each can be separatly plugged in, simplifying trouble shooting in case of faults. Sensor cable lead colors brown PE green white yellow 0V GND V 1 : bridge output signal V 4 : bridge supply voltage Connection / Wiring Please refer to the "Practice Guide of Web Tension Measurement and Control" for wiring instructions and the selection of the most suitable mounting location of the amplifier. Very important: Connect the shield of the sensor cable single sided on the amplifier side to protection earth (PE) with low resistance. Connect GND separately from the shield with PE. Additional recommendation: Connect the 0 V of the 24 V circuitry at a defined place prefably in close proximity of the PE. If this reference point is to be operated in the "floating point" mode, then the voltage between 0 V and PE should not exceed 50 Vpp. page 3

4 Operation HAEHNE Preparation Apply power to the amplifier with connected sensors. Wait 15 minutes to warm up. Ensure that the completely mounted sensors are loaded with the normal preload acting in the regular operating mode without any additional extraneous loads. In the case of Web tension sensors this is the roll weight without any web (foil, paper,...) Adjustment mode First press and hold the SET key to switch from the operating mode into the adjustment mode, afterwards press the menu key Ü briefly and release the SET key. The display indicates the 1. menu step which can now be changed. For the second, third and any additional menu step do not press the SET key instead use the menu key Ü to select the desired menu point, for instance, to make changes. Storing of changes Press the SET key until the LED goes OFF. This activates the adjustment procedure and the LED lights up until the procedure is completed. The amplifier switches now automatically into the operating mode. Leaving the adjustment mode without storage When exceeding the waiting time of 20 seconds the amplifier switches without changes automatically into the operating mode. An alternative is pressing the menu key beyond the 8. menu step. PreAdjustments / Operating Modes Display intensity (7. Menu step) select the menu step "display intensity" in the adjustment mode. increasing select the display intensity of the LEDs all four LEDs blink during the adjustment decreasing Filter type of the current output (1. Menu step) select the menu point "filter type" in the adjustment mode select the operating mode LED blinks during the adjustment if "FIL" was selected then the LED remains ON in the operating mode page 4

5 Output signal range (8. Menu step) select the menu point "output signal range" in the adjustment mode select operating mode The operating modes "bipolar" or "unipolar" must be selected before zero point and amplification adjustment! Operating Mode bipolar (factory adjustment) unipolar Signal Voltage Current output value output Option C Option N 100 % 10 V 4 ma 0 ma 0 % 0 V 4 ma 0 ma 100 % 10 V 20 ma 20 ma 100 % 0 V 4 ma 0 ma 0 % 5 V 12 ma 10 ma 100 % 10 V 20 ma 20 ma Display value (5. Menu step) select the menu point "display value" in the adjustment mode. selection alternatives: value of the numerical display in % (factory adjustment: 100 without a decimal point) or as actual value in the corresponding dimensional unit (decimal point display) 100 % corresponds to 10 V output voltage increasing The various decimal ranges are stepped through sequentially. The step velocity increases with the key holding time This adjustment deletes stored peak values! page 5

6 Adjustment of the parameters The input signal must not change during the following adjustment procedures Automatic zero point adjustment (2. Menu step) select the menu point "zero point adjustment" in the adjustment mode. ALTERNATIVELY: Manual zero point adjustment (2. Menu step) select the menu point "zero point adjustment" in the adjustment mode. select adjustment range move zero point, for instance by entering the weight of the web as a value store selection See also: Adjustment Modes on page2 adjustment range: % increasing decreasing The step velocity increases with the key holding time Entering amplification as gain value (4. Menu step) calculate amplification (siehe section "Adjustment Modes" on page 2) if no sensor is connected then terminals or have to be connected with each other. Select the menu point "Gain" in the adjustment mode select the desired amplification store the adjustment The zero point must be adjusted anew In case of manual zero point adjustment or in case of the unipolar operating mode adjustment range: increasing decreasing The step velocity increases with the key holding time ALTERNATIVELY: see next page page 6

7 Amplification adjustment with calibration weights (3. Menu step) adjust zero point (2. menu step) apply calibration weights to measuring a roll select the menu point "Cal" in the adjustment mode enter the percentage value of the calibration weight* adjustment range: % increase decrease The step velocity increases with the key holding time *Model the web geometry with a cable or rope and apply calibration weight. The weight should approximate the actual web tension in the operating mode. The DMA2 offers the facility to increase the weight with a percentage calculation. As an example: 70% of the required 100 kg are applied to the measuring roll. In the adjustment mode "Cal" 70.0 are entered representing the percentage value. Caution: If during zero point adjustment a value unequal to 0 has been entered then value adjustments are possible only in steps of 10%. rope or cable measuring roll amplifier calibration weight Fault conditions (Display) "Gain": The calculated amplification is out of range and is displayed in menu step 4. (calculated amplification as gain value) "null": The calibration weight is too small. page 7

8 Peak value display (6. Menu step) read stored peak values A change of the output signal range or the displayed value will return the display to null. erase the value with the "SET" key max. value min. value Fault display during operation Exceeding the maximum output signal voltage of approximately () 13.3 V e.g. resulting from a broken sensor cable. page 8

Strain Gauge Measuring Amplifier BA 662

Strain Gauge Measuring Amplifier BA 662 Original of the Manual Table of Contents 1. Safety precautions... 2 1.1. Field of application... 2 1.2. Installation... 2 1.3. Maintenance... 2 2. Function... 2