HART Smart Pressure Transmitter Calibration
How to calibrate a HART Smart Pressure Transmitter using The Fluke 754?
The accuracy and technology design of smart pressure measurement devices has totally improved in the past few year. Many old calibration instruments are unable to calibrate pressure transmitters nowadays due to its high accuracy. Higher technologies are required in order to calibrate state od the art pressure transmitters.
Verifying the performance of a HART smart pressure transmitter as will as and adjusting it requires a number of tools. Performing all this is never been easier with a HART enabled calibrator like the Fluke 754. It simplifies the task and reduces the tools you need to carry.
Install the pressure module adapter to the hand pump with thread seal before going to the field. Once the adapter is properly installed on the pump, changing modules to different pressure ranges is a snap, no tools required.
To get the accuracy needed to test these new high accuracy transmitters, match the pressure measurement standard range closely to the device tested. For example, use a 100 psi pressure module to calibrate and test a transmitter ranged at 100 psi. Industry standards suggest the measurement standard should be 4-10 times more accurate than the device being tested, so best-in-class accuracy is required.
The Fluke 754 Documenting Process Calibrator-HART utilizes the 750P series pressure module and has the HART functionality built in to enable smart trims on transmitters. It can also document transmitter performance before and
after adjustment and calculate pass/fail errors.
To perform the test:
- Isolate the transmitter from the process being measure and its loop wiring. If measuring the mA signal across the
transmitter test diode leave the wires intact, but note this method does not give the best mA measurement accuracy.
- Connect the mA measurement jacks of the 754 to the transmitter.
- Connect the pressure module cable to the 754 and connect the transmitter test hose from the hand pump to the
- Press the HART button on the calibrator to see the configuration of the transmitter.
- Press HART again and the calibrator will offer the correct measure/source combination for the test. If documenting
the calibration press As-Found, input the test tolerance and follow the prompts. If the measured mA signal at the
test points is found within tolerance the test is complete. If not, adjustment is required.
- Select, adjust, and trim the pressure zero, mA output signal and input sensor.
- After adjustment select As-Left, document the condition of the transmitter and after adjustment and if the test
passes, it is complete.
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