What is PID
What is PID
(OP)
Can anyone please explain me about the PID and its importance? I have very brief knowledge about it and what I know is PID helps to control the process but if some one can explain the elements of PID and how it works it will be very useful for me to understand and clarify my concept of PID and SCADA based Chromatography system.
Many Thanks in Advance
Many Thanks in Advance





RE: What is PID
thread798-113006
I'm presuming that is what you mean by PID, and I hope it helps to give you a perspective on what it is used for and its importance.
RE: What is PID
errors (proportional, integral, & derivative) from setpoint. The proportional error is based on the current deviation from setpoint. The integral error is based on the history of the deviation. The derivative error is based on the rate of change of the deviation.
RE: What is PID
I mean exactly what you told but this information is still bit difficult to get the complete idea about PID so if you can please elaborate on it for me.
Thanks a lot
RE: What is PID
RE: What is PID
In proportional control the amount of corrective action is proportional to the amount of error.
In derivative action the speed at which a correction is made depends on how fast the system error is increasing.
In integral control the control signal changes at a rate proportional to the error signal.
In P+I+D control, as rbcoulter said, the control signal is a linear combination of the error signal, its integral and its derivative.
RE: What is PID
The link provided by Guidoo appears to be a good place to start.
RE: What is PID
Best regards
Morten
RE: What is PID
I dont Know if you still need the information about PID
A simple way to understand is: The PID controller is the controller used by excellence to mantain a variable like temperature and concentration in a value that you fixed or your process fixed (set-point).
Everybody here said you the mean of P, I and D and if you dont have control process knowledges you cant understand it.
In a chromatography system the PID controller maybe mantain some reference concentration (if have it)or the temperature in the surface of solid (C Gas-Solid), in the entrance of analite, or any site of equipment that the temperature must be fixed in specific value.
RE: What is PID
John