PID settings for the control valve

There are pneumatic valves and solenoid valves, right? I’m not very familiar with these either; looking forward to everyone’s insights

The proportional-integral (PI) control law: Proportional control is a commonly used type of regulatory control that enables rapid elimination of the effects of disturbances and helps the system return to stability. However, since the ratio between the input signal and the output signal remains constant, residual errors persist in the system once it has reached stability； The role of integral control is to lag behind the presence of the deviation; it is unable to overcome the effects of disturbances in a timely manner, resulting in a slow adjustment process and difficulty in achieving stability ； The advantage of differential control is that, even when the deviation is small, it can automatically generate a strong corrective action at the moment when the deviation begins to change significantly. However, since differential control is related to the rate of change of the deviation, it is not used alone

I don’t quite understand, but our control valves sometimes have some errors.

You can enter a value and try it yourself to observe the valve’s operation

Could we do something more straightforward? That is, adjust the speed at which the integral control valve operates; increasing the differential component will cause various issues

Let’s stop talking about such complex calculus stuff and talk about something practical instead. We use foreign-made ones; they work well when there is a high flow rate, but not when the flow rate is low – it’s impossible to control them. We have to adjust them manually. For example, at the start of feeding, the TCS has a flow rate of only seventy or eighty units, and the pressure after the pressure regulator should be kept at 5.8 bar. Of course, it’s also important that the pressure in the buffer tank remains stable.

There’s no need to understand it in such complexity; just get it tuned properly

Reply to 3# yzhms, former leader: In actual production, how is it adjusted exactly? Could you tell us in detail?

Hehe, it mainly depends on the function of this control valve. For example, in ion membrane production, the regulation of chlorine and hydrogen is different. Chlorine: P 95, I 85, D 2. Hydrogen: P 600, I 25, D 2. Based on the PID data, the control valve for chlorine places greater emphasis on stability in regulation, avoiding excessive or rapid adjustments; whereas the control valve for the hydrogen main pipe primarily regulates the pressure difference between hydrogen and chlorine, which is an important parameter for ensuring the stability of the system as well as the safety of the electrolyzers and membranes. Proportional control is a commonly used type of regulatory control. It can quickly overcome the effects of disturbances and restore stability to the system. However, since the ratio between the input signal and the output signal remains fixed, there is still a residual value remaining in the system after it reaches stability ； The effect of integral control lags behind the presence of the deviation, and it cannot promptly overcome the influence of disturbances. This results in a slow adjustment process that is difficult to stabilize ； The advantage of differential control is that, even if the deviation is small, it can automatically generate a strong corrective action at the moment when the deviation begins to change rapidly; however, differential control is dependent on the rate of change of the deviation. Therefore, it is not used alone. The PID parameters for the main control valve are shown above. The parameters of the chlorine and hydrogen control valves differ mainly to ensure stability in the face of pressure fluctuations and sensitivity during the regulation process.

You can also refer to the article \"Operation Management and Optimization of Individual Electrolyzers\" from China Chlor-Alkali 201008, hehe.