Fault diagnosis and analysis in the use of intelligent differential pressure transmitters - Database & Sql Blog Articles

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Intelligent differential pressure transmitters are widely used in industrial applications. Jiangsu Xianda Instrument provides a detailed explanation of the working principle, common measurement methods, installation techniques, and important precautions. Additionally, it covers fault diagnosis and analysis to help users identify and resolve issues efficiently during operation.

The working principle of an intelligent differential pressure transmitter involves applying the differential pressure from both sides of the pressure guiding tube directly to the isolating diaphragm of the sensor. This pressure is then transmitted through a sealing liquid to the measuring component, which converts the differential pressure signal into an electrical signal. The signal is sent to the converter, where it is amplified or processed to produce a standard electrical output signal.

When using intelligent differential pressure transmitters, various faults can occur during the measurement process. Timely identification and analysis of these issues are essential for maintaining smooth production. Many of the troubleshooting techniques used for intelligent differential pressure transmitters are also applicable to general pressure transmitters due to their similar operational principles. Based on field experience, several effective diagnostic methods have been summarized.

1. Investigation Method: Review any events that may have occurred before the fault, such as fire, smoke, unusual odors, power fluctuations, lightning strikes, moisture exposure, human error, or improper maintenance.

2. Intuitive Method: Observe external damage to the circuit, leakage in the pressure guiding tubes, overheating of components, and the status of the power switch.

3. Detection Methods:

a. Disconnection Detection: Isolate the suspected faulty section from the rest of the system to see if the fault disappears. If so, the problem lies in that area. For example, if a HART-enabled smart pressure transmitter fails to communicate, disconnecting the power from the device and powering it via the field supply can help check for electromagnetic interference at around 2 kHz that might be affecting communication.

b. Short-Circuit Detection: Under safe conditions, short-circuit the relevant part of the circuit. For instance, if the output of the differential transmitter is too low, disconnect the pressure guiding tube and apply the differential pressure directly from the first pressure tap to both sides of the transmitter to test for blockages or leaks in the pilot lines.

c. Replacement Test: Replace the suspected faulty component with a known good one to determine if the issue has been resolved. For example, if the transmitter board is suspected of being faulty, temporarily replacing it can help identify the root cause.

d. Division Detection: Divide the measurement loop into sections—such as power supply, signal output, signal transmission, and signal detection—and inspect them step by step, starting from the simplest to the more complex parts. This approach helps narrow down the fault location systematically.