Actually another pole is added to filter high frequency noise. Now what is a pole?
I am a rookie as far as plc's go, but I have studied electronics and the math associated with them. That is my weak area, knowing specifically what applies when, where and how. The purpose of my above post was to point out that for each person the specifics with PID may be different. I probably should have just posted this:
P Proportional Band = 100/gain
I Integral = 1/reset
D Derivative = rate = pre-act
Then stated that there are 3 forms used serial, ideal and parallel but those terms may be different depending on manufacturer/person that is explaining it at the time.
Now as for what a pole is. I thought using Laplace transform was standard when Kirschoff's Law wasn't capable of doing the equations simply. Functions of s (the Laplace operator)are often defined in terms of their poles and zeros.
Now another way to look at a POLE is when you think of using bandpass filters...each path is a pole. If you create a filter for a certain bandwidth and it is in parallel to your working circuit that is a ONE POLE filter..add another filter circuit to pass another set bandwidth in parallel and then you have a TWO POLE OR you can use these filters to retune the resonant frequency...lot of options and variables involved.
NOTE: This is probably not a good explanation because I probably should use the math and pictures to show/explain better but I am not prepared for that and dont have the time right now.
LAST: My weakness is not in knowing the math but in lack of opportunity to actually DO. I study things continuously but at some point I have to actually do it to truly understand it. Thats one of the reasons I state that drives and other devices have their own PID options, I have used those alot and in most cases have found them so simple that an understanding of the theories etc isnt always needed. There is always some trial and error but that is to be expected. Some of the Drives out there now have to be programmed from scratch and that can be unique.
Yes I am a rookie with plc's, I am NOT a rookie at electrical/electronics, board level diagnostics,Troubleshooting, pneumatics, hydraulics, HVAC (yes have EPA card), general machine work (bearing, pulleys, mill, lathes etc), drives (AC/DC tho not in DickDV's class),computers (had MCSE 3.51 track, never upgraded it, had a business for 5 yrs). I have 5 kids all school age that take up my after work time, which I enjoy them doing.
Please dont stop with asking things like this.