PID explanations?

[novacustard]

Hi.

Hoping I can get some straightforward explanations of what each P, I & D actually affect when tuning servos.

The Parker Compumotor servos I have suggest increasing 'P' until the response can be seen to fluctuate around the target (ie the motor shakes!), then increase 'D' to cause it to damp down, then adjust P and D until the damping occurs quite close to the target.
So what is 'I' used for?
AFAIK, the values entered affect translate into milli or micro volts (not sure which), with values upto 800,000 being possible. What are typical values for servo tuning purposes - I've not dared enter more than 100, as between 5 and 35 seems to have a good effect.

Just need some good advice or pointers to this sort of info.

Thanks in advance,

Richard.

[Al_The_Man]

There is a good instructional/demo video's on PID tuning on the Galil site, It is obviously geared towards Galil but it is also general in nature.
Al.

[vacpress]

novacustard... search google with terms such as:

+PID +PDF +tutorial

+PID +Introduction

+PID +explanation

I have done this and found many documents.. Another good way to fully udnerstand mind be to look for a programming example in a programming language you are familiar with(if any). I finally 'got it' after disecting a basic stamp PID temperature controller...

Alternately, there is a thread here 'diy servo controller', or something of that sort, it has links to PID info..

[vacpress]

Here... Fine, for the google impaired...

Very Nice Site about PID: http://www.htservices.com/Applications/Process/PID1.htm

Thorough Tutorial :http://www.engin.umich.edu/group/ctm/PID/PID.html

Complex, with math: http://www.iau.dtu.dk/~jj/pubs/fpid.pdf

Basic Stamp specific:http://www.parallax.com/dl/docs/books/AlMay2002.pdf

'shareware tutorial(costs $, but still some free info)': http://www.jashaw.com/pid/tutorial/