Differential pressure transmitter is an instrument used in industries to measure the flow .Calibration procedure of DPT transmitter is what we are going to discuss
1. 24 VDC power supply
2. Multimeter digital
3. Pneumatic hand pump
4. Low pressure hand pump
5. High precision digital test gauge
6. HART communicator
Calibration procedure of DPT transmitter
1.Remove the differential pressure transmitter from the process
2. Make sure the equalizing valve manifold is closed.
3.connect the transmitter with the calibration equipments as shown in fig
4.Apply the LRV pressure with the hand held test pump and check the multimeter reading
5.If it is not 4ma then calibration is required
If transmitter is analog transmitter
6.By applying 0% pressure by test pump adjust the zero pot in transmitter to get 4ma output in multimeter.
7.apply 100% pressure and adjust span pot to get 20ma in multimeter.
8.check for 25%,50%,75%.
9 repeat the process to ensure that no error is occured.
In case of SMART Transmitter
We have to use HART communicator,connect the communicator with the transmitter select the HART Communicator Menu for lower range value trim and upper range value trim.
- Basic Set up – Calibration – Zero Trim/Sensor Trim —Lower/Upper range value trims.
- HART communicator will automatically calibrate the transmitter.
- Restore the process connection
- Take the transmitter on line. Ensure there is no leak