How to calibrate the analog output of a PXU process control

16 Jun 2025

Please note

The controller has been fully calibrated at the factory. Scaling to convert the output signal to the desired display value is performed in Configuration Module 2, Output Parameters. If the controller appears to be outputting incorrectly or inaccurately, refer to Troubleshooting before attempting to calibrate the controller. 

 

Calibrating the unit to correct when the controller appears to be outputting incorrectly or inaccurately, even after troubleshooting with the factory. 

 Recalibration should only be performed if necessary and only by qualified technicians using appropriate calibration equipment.

 

APPLICABLE PRODUCTS 

  • Any PXU series process control 

PRE-REQUISITES 

  • Precision multi-meter
  • For all calibrations, allow the controller to warm up for 30 minutes minimum and follow the manufacturer’s warm-up recommendations for the calibration source or measuring device.
  • Module 2 program parameter may be changed during calibration.  Entering Code 48 will require that Output Parameters (Module 2) be verified after calibration is complete.

 

IN THIS ARTICLE 

  • Testing analog output
  • Calibrating the analog output low range
  • Calibrating the analog output high range
  • Calibrating the retransmit output (model dependent)

 

 Test

There may be a desire to test the output to verify OP1 analog output range, without accessing the calibration menu. One of the easiest tests is to configure the input type as a thermocouple, then wire a thermocouple or jumper wire (should read ambient) to the input.

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Then place the unit in on/off control and verify that the output is properly configured to output 4-20mA between 0-100% output power.

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Finally, change the setpoint to a value less than the PV, the output should be 4mA. Next, change the setpoint to be greater than the PV, the output should be 20mA. If the output is not correct, proceed to the next section.

Another option, after verifying the analog output configuration matches the above, is to simply place the unit into manual mode and adjust the manual power.

 Main Analog Output Calibration

In order to calibrate the analog output, enter the Factory Service menu and select code 48

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Analog Low

Press the P key 8 times (top display will read A1-L). Use of the P key will advance to the next selection, unless a modification was made to the current selection; at which point the modification will be stored, but the selection will not be advanced.

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1. Modify the value
2. Press P
3. Measure the output
4. Repeat 1-3 until desired output (4mA) is reached

Analog High

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1. Modify the value
2. Press P
3. Measure the output
4. Repeat 1-3 until desired output (20mA) is reached

Factory Reset

After calibration is complete, a factory reset is required in order for the unit to function properly.

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Exit Factory Service menu by pressing P until the display returns to the Main Display Loop.

Retransmit Analog Output Calibration

In order to calibrate the analog output, enter the Factory Service menu and select code 48

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Analog Low

Press the P key 8 times (top display will read A1-L). Use of the P key will advance to the next selection, unless a modification was made to the current selection; at which point the modification will be stored, but the selection will not be advanced.

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1. Modify the value
2. Press P
3. Measure the output
4. Repeat 1-3 until desired output (4mA) is reached

Analog High

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1. Modify the value
2. Press P
3. Measure the output
4. Repeat 1-3 until desired output (20mA) is reached

Factory Reset

After calibration is complete, a factory reset is required in order for the unit to function properly.

 

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Exit Factory Service menu by pressing P until the display returns to the Main Display Loop.

 

ADDITIONAL INFO 

PXU Product Manual 

PXU Product Manual 

 

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