Questions regarding the use of thermistor signals in control and regulation
Thread Content
I’ve heard that in a temperature control loop, it’s best to convert the PT100 signal into a 4–20mA signal before adjusting the control valve. Is this statement correct? What are the regulatory bases?
Converting it to a 4–20mA signal facilitates signal transmission; for single temperature control, the Pt100 thermistor can be connected directly to the temperature controller without any conversion needed.
Any signal will do; in any case, it has to reach the controller. The control of the control valve is carried out by the controller, which calculates the necessary outputs. It’s like the eyes and hands: without instructions from the brain, even if the eyes can see, the hands won’t move – they are disconnected from each other
Both RTD and 4-20 mA signals are acceptable; direct temperature single-loop control is not very good due to severe lag. It is best to think carefully when choosing the control scheme