DP transmitter Calibration is a procedure in which we ensure the linearity and response of a DPT.
1. 24 VDC power supply
2. Multimeter digital
3. Pneumatic hand pump
4. Low pressure hand pump
5. High precision digital test gauge
Procedure of DP transmitter Calibration
1:- Ask panel operator to put the controller in manual mode for control loop and to put it on MOS for ESD.
2:- Hook up HART Communicator and verify some parameters by refer to data sheet. Typical parameters are, tag number, PV, LRV and URV.
3:- Remove the differential pressure transmitter from the process
4:- Make sure the equalizing valve manifold is closed.
5:- Connect H.P. tapping of the transmitter with the calibration equipmenten and L.P. tapping open to atm as shown in fig
6:- Apply the LRV pressure with the hand held test pump and check the multimeter reading, if output is not 4mA adjust zero with button or HART
7:- Apply the URV pressure with the hand held test pump and check the multimeter reading, if output is not 20mA adjust span with button or HART
8:- Verify the linearity by increasing and decreasing the pressure (0%, 25%, 50%, 75%, 100%, 75%, 50%, 25% and 0% of range)
9:- Take the transmitter in line and ensure that there is no leak.