Basic analysis steps for faults in the field instrumentation system

Posted by igeelee on May 8th, 2019

On-site instrumentation measurement parameters are generally divided into four parameters: temperature, pressure, flow, and liquid level.hose crimping tool.

According to the different measurement parameters, different field instrumentation faults are analyzed.

1. First, before analyzing the faults of the instrumentation in the field, it is necessary to thoroughly understand the production process, production process conditions and conditions of the relevant instrumentation system, understand the design scheme and design intent of the instrumentation system, and the structure, characteristics and performance of the instrumentation system. Parameter requirements, etc.

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

3. If the instrument records the curve as a dead line (a line with no change at all), or 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 recording curve is abrupt or jumps to the maximum or minimum. The fault at this time is also often in the instrumentation system.

5. Before the fault occurs, the meter recording curve has been normal. After the fluctuation, the recording 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 instrument is not normal, you can go to the site to check the indication value of the same intuitive instrument. If they are very different, it is likely that the instrumentation system has failed.

In short, when analyzing the cause of faults in the field instrumentation, special attention should be paid 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 instrumentation system. Therefore, we must comprehensively consider and analyze the two aspects of the field instrumentation system and the process operating system to check the reasons.