We consider flow control a fundamental control technique. Flow controls are used in all types of applications:
There are several types of flow control.
In simple flow control, you typically are simply detecting if there is flow or no flow. Although this type of control is very easy and simple to implement, it is not able to maintain a setpoint flow in the line.
In proportional control typically the tank flow is an analog signal that accurately indicates the current flow in the pipe. The controller is typically a PID controller that controls an analog output based on the current flow and the setpoint. For example, if you want a pipe to maintain a flow of 12.5 gallons per minute, you would get an accurate flow meter, scale the flow meter output to your units and then feed that flow to the PID controller. The PID controller would then control a valve or pump to maintain the flow. You can often maintain very tight flows using proportional control.
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