tunning PID
tunning PID
(OP)
I am dealing with a pid controller which has to regulate a flow as follows:
Set Point: 60 mc/h
Manipulated variable is a flow control valve.
Now, in practice I have noticed that the reaction time is very slow. Considering I can make a tunning and I can change, the "gain", the "integration time", "derivation time", please tell me if you know, how can I set these parameters of the PID. Should I increase the gain? Now the gain is around 30.
Thank you
Set Point: 60 mc/h
Manipulated variable is a flow control valve.
Now, in practice I have noticed that the reaction time is very slow. Considering I can make a tunning and I can change, the "gain", the "integration time", "derivation time", please tell me if you know, how can I set these parameters of the PID. Should I increase the gain? Now the gain is around 30.
Thank you





RE: tunning PID
attached is a document that may provide guidance.
if this does not help, i've another PID tuning document that I've used many times for tuning PI control loops. it worked nearly every time I used it.
post a request and i'll search for it and attach.
good luck!
-pmover
RE: tunning PID
RE: tunning PID
You can download it for free at: http://www.scilab.in/
I actually used to simulate the response of a second order system to a degree function with different values of "gain", "integration constant" and "derivation constant"
RE: tunning PID
I would recommend that you either find somebody who know - or let it be.
Sometimes "slow response" is needed in order not to get a unstable system. It may work fine for a while untill something else changes...
I dont think there will be much use in looking at simulation tools unless you know and understand the theory.
Best regrads
Morten
RE: tunning PID
Is important to understand that the gain of the PID is not always the key to adequate the response of your system. Can make it unstable
The best thing is knowing your system behavior and equationate it, but if it is not possible because of the complexity you can infer the behavior by changing control parameters in a simulator with a simpler equation.
The derivation time can actuate fastly over the system's reaction time, but is dangerous because of its sensitivity to fluctuations
The use of integration time is to eliminate the offset of the final reponse, but its not so useful if you are trying to lower your reaction time.
RE: tunning PID
- for P, increase the gain value or decrease the proportional band value, depending on which your device uses [probably gain according to your post]
- for I, decrease the value if units are minutes (or time units) [increase the value if the units are repeats/minute, but your post indicates integral time]
- for D, increase the value
It might prudent to make a record of the values you started with and increase only one at a time.
RE: tunning PID
Best regards (and luck)
Morten
RE: tunning PID
You are no dealing with children...
Your last comment was totally unnecessary. If you don't want to help we don't need your help
RE: tunning PID
Good luck
RE: tunning PID
thanks
RE: tunning PID
Or you can learn some basic control theory, just a little can help.
Francis
www.controldraw.co.uk
www.s88control.blogspot.com
RE: tunning PID
Francist, cant really determine if you are ironic?
Best regards
Morten
RE: tunning PID
If you don't know what integral and derivative do it is unlikely that you will be able to tune the loop reasonably.
Francis
www.controldraw.co.uk
www.s88control.blogspot.com