【Weekly 3 Questions, Question 9】2017.8.29
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This post was last edited by xh8618 on 2017-8-29 at 13:26. bg9.png (Question): To determine the reasons for unstable output from a differential pressure transmitter, what aspects should be checked? Check whether the power supply to the transmitter is stable. Check for any loose connections in the circuit, as well as issues related to grounding or short circuits/opens. Verify whether there are any fluctuations in operating conditions. Check if there is liquid accumulation in the gas pipeline and gas in the liquid pipeline. Examine whether the transmitter’s output module is functioning properly.—————————————————————————————————————————————————————————————— The deadline for submitting answers is one week; no scoring will be given after this period. Once the deadline passes, the answers will be displayed automatically. The deadline is 207.09.5. Scoring criteria: 2 Wealth points for incorrect answers; 3–6 points for *incomplete* answers; 8 Wealth points for correct answers accompanied by a detailed explanation; 10–15 Wealth points for correct answers with additional *complementary* information. Please score according to these criteria. Note: If there are editing records after answering, only points will be awarded to those who participated. For continuous malicious spamming, 2 points will be deducted each time, with no upper limit. Pure numbers, pure emojis, or random letters that have nothing to do with the answer are all considered malicious spamming; points will start to be deducted after three warnings.
1: Check the transmitter body and the three-valve assembly; open the balance valve to verify whether the differential pressure returns to 0. 2: Check the conductivity of the pressure lead pipes
A. The stressor itself is an unstable pressure. B. The instruments or pressure sensors have weak interference resistance. C. The sensor wires are not securely connected. D. The transmitter terminals are not firmly connected to the signal wires. E. The diameter of the signal transmission line is small (the wire is too thin or the copper core contains impurities). F. The sensor itself vibrates very heavily. G. The sensor is faulty.
1. The main reasons for an excessively low output from a differential pressure transmitter are: leakage or blockage in the pressure tube, an excessive range setting for the differential pressure transmitter, or too low flow rate within the pipeline. For ordinary fluids being measured, it is impossible for the pressure guide tube to leak or get clogged. This phenomenon usually occurs when measuring gas or media containing impurities on-site; in such cases, we need to inspect the pressure guide tube, remove any blockages, adjust the range of the differential pressure transmitter, and regulate the process flow rate. 2. The main reason for an excessively high output differential pressure is the exact opposite of what was mentioned above; one can refer to the solutions provided earlier to address this issue one by one. 3. The output differential pressure is unstable and subject to large fluctuations. An incorrect installation direction, as well as disturbances from valves upstream and downstream, along with the influence of elbows on other flow-blocking elements, have the greatest impact on the throttling element; this requires us to adjust the process or change the installation location.
Switch to another table to see if it’s stable; if it is, there’s an issue with the table. Otherwise: 1. The process medium itself is unstable; 2. Pressure tapping leakage; 3. Interference; 4. Poor contact
1. Are there any foreign objects in the pressure guide tube? 2. Is there any leakage in the pressure guide tube? 3. Is the differential pressure transmitter misconfigured or is there a problem with its power supply?； 4. Large fluctuations in medium pressure, liquid level, or density
Reasons related to the process or excessive vibration in the pipeline instrumentation; unstable power supply; electromagnetic interference; faults in the conversion unit; the damping time setting for the instruments is too low
l. Wiring circuit. Check the circuit for intermittent short circuits, open circuits, or multiple ground faults ； Check whether the voltage applied to the transmitter is appropriate ； 2. Ensure that the contact points of the connectors are clean, and check the grounding of the sensor components. 3. Check whether there is liquid in the gas pressure guide tube, and whether there is gas in the liquid pressure guide tube. 4. Fluctuations of the liquid being tested. Adjust the level of damping in the circuit. 5. Use a spare circuit board to replace the faulty transmitter circuit board in order to diagnose the issue and replace the defective circuit board.
1. Are the pressure tapping valve and pressure tapping wires conducting? 2. Is the circuit stable? 3. Are there any disturbances in the vicinity? 4. Is the damping time too short? 5. Is the operating condition unstable?
Is the power supply to the transmitter stable? Are there any fluctuations in operating conditions? Are there any loose connections, short circuits, or open circuits in the circuit? Check whether there is liquid accumulation in the gas pipeline and whether there is gas in the liquid pipeline. Verify that the transmitter’s output module is functioning properly