PID parameter setting during cascade control of control valve
Thread Content
How to set the pid parameter during cascade control of control valves?
Cascade adjustment should be to set the PID parameters of the regulator. There are two modulated variables in cascade regulation. It depends on which one is the main variable and which one is the auxiliary variable. For example, if it is temperature regulation, there is no need for practical differential. Other parameters may need to use differential. Then they can be set according to the three methods of PID setting. Generally, the empirical method is used to set the PID parameters. In fact, it is similar to single-loop regulation.
Upstairs... the temperature adjustment should use differential PID adjustment... for other adjustments, just use PI...
Should I use differential? ? ? ?
Cascade adjustment generally uses a two-step tuning method. Other: For controlled variables such as pressure and flow, the time constant T0 of the object adjustment channel is small, and the load changes rapidly. At this time, both the differential action and the integral action will cause oscillation, which has a great impact on the quality of adjustment, so the differential adjustment law is not used. For systems with large time constants in measurement channels and adjustment channels such as temperature and composition, using the differential law as an advance adjustment can achieve good results.
Seniors, would you like to adjust the auxiliary circuit first, and then adjust the main circuit settings? Treat the auxiliary circuit as a single circuit and the main circuit as a single circuit. Then set the PID parameters according to the controlled variables and variable characteristics of each single loop?
I'm very sorry. I discovered the error when I opened my post today. Differentials should generally be used for temperature adjustment, but differentials may not be used for other parameters. I would like to solemnly say sorry to everyone!