I/P Converter calibration


#1

Current to pressure (I/P) converters receive an electrical current signal in a range of 4 - 20 mA and provide a corresponding pneumatic signal in a range of 3 - 15 PSI. The I/P converters are used in valve positioner, where a controller sends an electrical signal to I/P converter and the converter sends a corresponding pneumatic signal to valve positioners that control the valve.

Calibration of I/P converter:

Required Apparatus:

  1. Air Filter Regulator
  2. I/P Converter
  3. Master Pressure gauge (For Measurement of I/P Output pressure)
  4. mA Source (to feed mA to I/P Converter)

Calibration Procedure:

  • First remove the module final assembly from the housing.

  • Position the range jumper in the Hi position for High Range

  • Connect air supply to the input port, which is connected through the air supply regulator.

  • Connect the output signal port with an accurate output indicator.

  • Make sure the port of the output gauge is installed with an output gauge or a threaded plug. A threaded plug is provided for units shipped without output gauges.

  • Apply a 4.0 mA signal (Vm = 1.0 V) and adjust the zero screw to reach the output of 3.0 psi. The output increases with the zero screw rotation in the clockwise direction.

  • Repeat the last two steps to verify and complete the calibration.