How To Calibrate Pressure Transmitter.

How To Calibrate Pressure Transmitter./ Procedure for Pressure Transmitter Calibration.

Types of equipment required:-

1. Pressure transmitter
2. Multimeter
3. HART communicator
4. Handheld test pump (pressure source).

Procedure OF Pressure Transmitter online calibration:-

1. Isolate the Pressure Transmitter from the Process.
2. Slowly open the vent plug and the vent valve to release the pressure.
3. Connect the multimeter with the transmitter and ensure that output is4ma when 0% pressure is applied.
4. Connect the handheld test pump (pressure source) to the transmitter.
5. Ensure there is no leak.
6. Apply pressure range at 0%, 25%, 50%, 75%, and 100% and check
7. there is an error.
8. If there is any error calibration should be done.

If the transmitter is an analog transmitter

1. Apply 0% pressure as per LRV with handheld test pump and check multimeter if it is not 4ma adjust the zero pot in the transmitter and correct transmitter output to 4ma
2. Apply 100%pressure as per the URV and correct 20ma in multimeter by adjusting span pot in the transmitter  
3. NOTE: Repeat these steps to rectify the error.

In case of SMART Transmitter

We have to use HARTcommunicator.Connect the communicator with the transmitter select the HART Communicator Menu for lower-range value trim and upper range value trim using the below steps.

1. HART communicator will automatically calibrate the transmitter.
2. Restore the process connection
3. Take the transmitter on line. Ensure there is no leak.

For an example of five-point calibration is given below:-

            Low range value = 0psi

            Upper range value = 200psi

PERCENTAGE OF RANGE(%)	INPUT PRESSURE	OUT PUT CURRENT (IDEAL)
0%	0 PSI	4.00 mA
25%	50 PSI	8.00 mA
50%	100 PSI	12.00 mA
75%	150 PSI	16.00 mA
100%	200 PSI	20.00 mA
75%	150 PSI	16.00 mA
50%	100 PSI	12.00 mA
25%	50 PSI	8.00 mA
0%	0 PSI	4.00 mA