Can the moving average of process parameters be displayed in DCS?
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The measurement values of some process parameters exhibit high fluctuation frequencies, sometimes even showing periodic fluctuations, and such fluctuations are difficult to eliminate. Do current DCS systems or related instruments have the capability to display moving averages? Such as a moving average of dozens of seconds, or a few minutes? If possible, can this moving average be controlled through a feedback loop?
The DCS systems I’ve seen can’t display it that way; if it were possible, it would be a newly developed module
I think it’s possible to do it from within, like by writing a program; I’m not sure if that’s correct
If the fluctuations in the measured values within the control loop are an issue, these fluctuations can be eliminated through PID tuning. The situation you described is one of unstable operating conditions; the instruments should be able to measure the true values of the parameters, and it should not be the DCS that eliminates such fluctuations. Otherwise, false readings will be generated, affecting the proper operation of the process.
Some measurement fluctuations seem to be inevitable and cannot be eliminated; they are also acceptable from a process perspective. For example, measuring the flow rate of saturated steam often results in fluctuations in the measured values, and fluctuating liquid levels can also cause variations in the level measurements. However, such fluctuations pose significant challenges for automatic control, which leads me to wonder whether it would be possible to use moving averages instead of the direct measured values for control purposes. Let me clarify: I work in the field of manufacturing processes, not in instrumentation.
Then you just need to adjust the set value of the regulator, so that the control loop uses the average value of the fluctuations as its set point
It should be possible to display, but the self-control functionality is unclear