How to diagnose differential pressure transmitter failure

Transmitters always have various faults during measurement. Here are the methods of fault diagnosis.

(1) Investigation method: Review the fire, smoke, odor, power supply changes, lightning, wetness, misoperation, and mis-maintenance prior to failure.

(2) Intuitive method: to observe the external damage of the circuit, the leakage of the pressure guiding tube, the overheating of the circuit, and the status of the power supply switch.

(3) Test method:

Disconnection detection: Separate the suspected faulty part from other parts to see if the fault disappears. If it disappears, determine the fault. If not, proceed to the next step. For example: The smart differential pressure transmitter can not communicate with Hart remotely. Disconnect the power from the meter body and use the on-site power supply method to power the transmitter for communication to see if the cable is overlaid with an electromagnetic signal of about 2 kHz to interfere with the communication.

Short-circuit detection: in the case of ensuring safety, the relevant part of the circuit is directly shorted, such as: the output value of the differential transmitter is too small, the pressure tube can be disconnected, and the differential pressure signal is directly induced from the pressure-receiving valve at a time. To the two sides of the differential pressure transmitter, observe the output of the transmitter to judge the continuity and blocking of the pressure-conducting pipeline.

Replacement test: Replace the suspected defective part and determine the fault location. For example, if you suspect that the transmitter circuit board has failed, you can replace it temporarily to determine the cause.

Branch detection: The measurement loop is divided into several parts, such as: power supply, signal output, signal transmission, signal detection, according to sub-section inspection, from simple to complex, from the table and in, narrow the scope, to find the fault location.