Is it a problem with the PID parameter settings or with the positioner of the control valve?
Thread Content
The amplitude of the valve position opening curve of the control valve fluctuates too much – is it a problem with the PID parameter settings? Is it still a problem with the locator?
PID parameter settings are more likely to be the root cause of the problem, while issues with the control valve actuator are probably only a secondary issue; they are often resulting from incorrect parameter settings or improper PID control.
It’s easy to determine: In the first step, set the DCS PID loop to manual mode and manually adjust the valve positions to see if there are any fluctuations in the trend. If there are no fluctuations when it’s in manual mode but fluctuations occur when it’s in automatic mode, then the PID parameters are not appropriate； If there are fluctuations even when operating manually, then check the locator for problems
I think the specific reasons need to be analyzed in detail; it’s not something that can be resolved just by looking at a curve. PID control can only help alleviate oscillations. The cause of the oscillation could be process issues or instrument design problems.
With this highly regular pattern, the problem lies in the PID parameter settings.
The process has been checked and there are no issues; the problem lies in control. The reaction pressure is controlled by the amount of circulating water used; although the valve position fluctuates significantly, the pressure curve remains relatively stable. But the valve position amplitude of other reactors is smaller.
PID parameters and the year are issues related to control logic.
. It’s possible for either. This is the result of the response times of the control system and the process approaching each other; both the amplification factors of the regulator and the positioner can cause this phenomenon. For analysis and judgment, reference can be made to the answer on floor 3. There is a high likelihood that personal judgment is influencing the adjustment parameters. For the positioner, if it has knobs similar to those for \"damping\" and \"gain\", try increasing the damping or decreasing the gain ； For the adjustment parameters, the derivative can be turned off and the integration time can be increased. .
How are you sure there’s no problem with the process engineering field? I would like to ask you what the distance is between the control valve and the reactor. Generally, the flow rate of water is around 2 meters per second; how long does it take for the signal to travel from the control valve to the reactor? Is there any possibility of delay in the detection process? These are all process-related issues. You are underestimating the complexities of automation engineering – you think that working with instruments simply means dealing with 4-20mA signals and adjusting PID settings.