When the valve does not move, the flow rate remains very stable; automatic control is required – how should the PID parameters be set?
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With manual control, the valve is rarely adjusted, resulting in stable flow; once automatic control is activated, the valve opens and closes repeatedly, causing fluctuations in flow. How should the PID parameters be adjusted in this situation? Are there any empirical values that can serve as a reference? Dear teachers: hug:
Find a book on Process Control and read it by yourself.
Because the flow measurement signal contains noise, the control valve acts frequently and rapidly. Filtering the flow measurement signal can be considered.
Is the control valve used for flow control or level control?
https://www.bilibili.com/video/BV1oU4y1K7T8/?spm_id_from=333.999.0.0 You can watch videos on PID tuning from Kongxueyuan; PID tuning is a complex topic that cannot be mastered in just a few days of study. Additionally, you can check out the WeChat public account HukanPID. The specific method of adjustment depends on the type of DCS system you are using; different systems have different PID formulas, and the units of the final parameters also vary. Taking the Yokogawa DCS as an example, for flow control the PID parameters are P: 100–500 and I: 15–50
There is no reference value for this; the PID parameters need to be adjusted gradually based on the actual operating conditions on site. Initially, a value for the PID parameters can be assigned in advance, by referring to the parameters of similar control systems within the company. If such references are not available, the parameter setting can be carried out first with proportional control, then with integral control, and finally with differential control.
This post was last edited by liu530014416 on 2023-2-13 09:56. There’s no need to adjust the PID; trying to do so will be ineffective in this case. It is suspected that the issue lies with the locator, and replacing it with a new one doesn’t help either. I have 2 units with the same issue; one is installed behind the heat exchanger, and the other is installed in front of it. 1. Replace the control valve ； 2. Increase the distance between the control valve and the flow meter.
PID parameter tuning cannot be explained in just a couple of sentences; it requires experience and accumulation