How to use an intelligent PID controller to control the start and stop of the pool level pump
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Use an intelligent PID controller to regulate the liquid level in the tank. The pump is activated to fill the tank when the level is below 20%, and it stops running when the level is above 80%. The system consists of one pump, one controller, and one level transmitter. How should the wires connected to the controller’s terminals be arranged (the two alarm relay output terminals of the controller, as well as the OUT relay output terminal)?
Actually, you can fully utilize the high and low alarm functions of the digital display; treat them as stop and start buttons, and then you’ll understand it
The normally open alarm output is connected in parallel to the start terminal of the pump control circuit, and this alarm threshold is set to a low-level alarm； The normally closed alarm output is connected in series in the control power supply circuit, set to a high alarm level.
The poster uses on-off control, that is, by setting the upper and lower output limits of the regulator, without the need for PID control.
By utilizing the alarm hysteresis function of the digital display, a single alarm output can be used to control the upper and lower water levels
There is absolutely no need for a control valve; just buy a float level switch. When the level drops to a certain threshold, the pump starts automatically, and when it rises above that threshold, the pump stops.
The original poster might have been influenced by foreigners or foreign intermediaries, complicating simple matters so as to make more money. The start and stop of the pool level pump can be handled using on-off control; it’s not like the level control of tower equipment in process production, where accuracy is required.
No PID is needed; it can be achieved with simple control programming.