Now analyze the different field instrument faults according to the different measurement parameters.

1. First of all, before analyzing the field instrument failure, it is necessary to thoroughly understand the production process, production process conditions and conditions of the relevant instrument system, understand the design scheme, design intent of the instrument system, the structure, characteristics, performance and parameter requirements of the instrument system.

  2. Before analyzing and inspecting the faults of the on-site instrument system, it is necessary to understand the changes in the load and raw material parameters of the production operators, check the record curve of the faulty instruments, and conduct a comprehensive analysis to determine the cause of the instrument failure.

3. If the meter records a dead line (a line that has no change at all), or if the recorded curve is originally fluctuating, it suddenly becomes a straight line; the fault is likely to be in the instrumentation system. Because most of the current recording instruments are DCS computer systems, the sensitivity is very high, and the change of parameters can be very sensitive. At this point, you can artificially change the process parameters to see the curve changes. If it does not change, the basic conclusion is that the instrument system has a problem; if there is a normal change, it is basically determined that the instrument system has no major problems.

4. When the process parameters are changed, it is found that the recorded curve is abrupt or jumps to the maximum or minimum, and the fault at this time is also often in the instrument system.

5. Before the fault occurs, the instrument record curve always shows normal. After the fluctuation occurs, the record curve becomes irregular or the system is difficult to control, and even the manual operation cannot be controlled. At this time, the fault may be caused by the process operating system.

6. When the DCS display meter is not normal, you can go to the site to check the indication value of the same intuitive meter. If they are very different, it is likely that the instrument system has failed.

In short, when analyzing the cause of the field instrument failure, pay special attention to the changes in the characteristics of the controlled object and the control valve, which may be the cause of the failure of the field instrument system. Therefore, we must comprehensively consider and carefully analyze the two aspects of the field instrument system and the process operating system to check the reasons.