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How and where to use PID controller?

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hiyan

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i wantto ask about PID controllaer where i use p wheere and which sitvation i use I and D ?2nd if i wantto controll motor speed through PID in which manner i mean where i use integral where i use d and p?
 

epp

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Re: PID

P-proportional
It is used adjust response of your controller. If too big you will have large overshoot and oscillations in controller response (motor speed etc.). First you adjust this parameter.
I-integral
It is used to minimize steady state error. It should be small othervise you will cancel P part. This parameter is adjusted after tuninig of P part.
D-derivative
It is used to compensate large change of error (d(err)/dt). Usually one doesn't use it because it relies on data in "future". This paparemeter is tuned last.
 

hiyan

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Re: PID

if i wantto controll MAchine speed like i wanna constant speed of machine which integral i will us e?
 

epp

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Re: PID

Integrator is formed by an operational amplifier if you want to realise it in analog otherwise is digital. Try to do some serach in www. I found some good file about it but I cannot remember where I save it. When you make your controller you have to make it work then do fine tuning of your response by changing P and I term.

Regards.


P.S.
Please click helped.
 

electronics_kumar

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Re: PID

hiyan said:
i wantto ask about PID controllaer where i use p wheere and which sitvation i use I and D ?2nd if i wantto controll motor speed through PID in which manner i mean where i use integral where i use d and p?
I controller will reduce steady state error by increasing order of the system(also it will increase the number of zeros)
D controller will reduce overshoot by increasing damping of the system.....(it will also increase the number of zeros like I controller)
 

hiyan

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Re: PID

Again question is which part of controller keep Motor speed constant ?




I ,p or D:?:

kindly explain me .thanks
 

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PID

Have a look at Microchips website and application notes for motor control. Lots of examples and c code to implement constant speed. Normaly, a PI controller will do the trick.
 

mobile-it

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Re: PID

atc9443 said:
Great sites to learn about PIDs

h**p://www.learncontrols.com
h**p://www.jashaw.com
also, PIDs with matlab and simulink tutorials:
h**p://www.library.cmu.edu/ctms/ctms/pid/pid.htm
I think the first link has to be: http://www.learncontrol.com
 

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