pid control

Anyone know of a good source of either PID parameters for various controlled fluids or a plain explanation of how to determine the P, I, D values

On one of the technical leaflets of Eliwell (INvensys) or Dixell is explained how you can do this.

But even the, it stays always a little bit trial and error.

You just can't calculate this on forehand. You first have to look how fast the process is changing and how far the overshoots are in simple on/off (mostly with on/off settings or setting the PID in such a way that it acts as simple on/off)
Then you can calculate better how to set the PID.
That's anyway how we do it and how it's described in some handbooks.

http://aabi.tripod.com/optimumpid/ex...-pid-egnsr.htm
http://lorien.ncl.ac.uk/ming/pid/PID.pdf
http://www.lakeshore.com/pdf_files/A...ppendixF_l.pdf
http://www.advice1.com/pid.htm
http://home.hccnet.nl/e.vd.logt/htm/regelen_pid_uk.htm

The explanation of Eliwell or Dixell was a more practical one. Haven't time now to serach for it.

Thanks Peter!
No problem fgrgrcprklmn:mad:

You are welcome Peter. It seems you found another thankful customer.:(

Makes you feel like making the first reply as "Yes I have and you?"

Will do this the next time they make the first time a post like this.

Hello All,

as far as I know the Eliwell controllers that has the PID management has also the self-tunning alghoritm, so it's not needed to calculate the right setting but just a fine tunning might be done manually