How to calibrate Differential pressure gauge (DPT) level transmitter at field?

Equipment required:

  • Datasheet,
  • Pressure calibrator,
  • Multimeter,
  • Hart communicator

Procedure of DP Level Transmitter Calibration at field:


  • Man placed the computer in the control circuit manual mode and placed it on the ESD circuit MOS.
  • Refer to the datasheet to hook up HART Communicator and check some parameters. Typical parameters are PV, LRV and URV tag amount.
  • Isolate from the method of the tool.
  • Release both pressure and drain low and high side liquid throughout the manifold drain.
  • Open both plugs at seal pot.
  • Top up seal liquid for the low side until half of the seal pot.
  • Remove tubing at the high side of the manifold.
  • Hook up the calibrator on the at high side and isolate the vent valve
  • To evaluate the present signal, hook up a multimeter in sequence with the signal to the DCS.
  • If the amount equal to zero is applied as per calculation, the multimeter should display 4mA.
  • If not, use HART Communicator to adjust zero at the transmitter
  • Apply pressure according to the calculation if the amount is equal to 100%, the multimeter should show 20mA.
  • If not, use HART Communicator to adjust the receiver
  • After finishing the task, request the board driver to return loops to normal mode or to normalize the MOS.
  • Fill out and submit the calibration form for future reference.
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