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[DPRG] Re: DPRGlist Digest, Vol 69, Issue 20

Subject: [DPRG] Re: DPRGlist Digest, Vol 69, Issue 20
From: Bill Cooke bcooke at cookedata.com
Date: Tue Feb 23 13:05:44 CST 2010

embedded:
> Message: 1 Date: Mon, 22 Feb 2010 12:34:02 -0600 From: "Quinones,
> Jose" <jquinones at ti.com> Subject: [DPRG] PID Loop Question To:
> "dprglist at dprg.org" <dprglist at dprg.org> Message-ID: 
> <7B4574D56E4ADF438756313E9A172A8797F71B90 at dlee01.ent.ti.com> 
> Content-Type: text/plain; charset="us-ascii"
> 
> Hi Group,
> 
> I am trying to get a better understanding of the PID Loop. I have
> some, but want to understand it as good as I understand tying up my
> shoes. I want this to be as clear in my head as it is counting from 1
> to 10 in Spanish.
> 
> So far, I think I understand the Proportional aspect this good. If
> the error is big, correct a lot. If the error is not so big, correct
> just a little bit.
> 
> I think I have an idea of what Integral is. If the error has been big
> for a long time, correct for a longer period of time. If the error
> has not been too large for a long period of time, then apply a
> correction only for a small period of time.

I'm no expert on PID, but a little warning. A correction can be large if 
applied longer, or if simply applied for the same time at a large 
magnitude.  The effect of the correction's duration is a function of the 
device. Seven jabs doesn't always equal a right cross.

-- Bill

> 
> Not certain if I follow Derivative as well, but my impression is that
> it tells us how quick the error is changing and if so, then apply a
> correction.
> 
> And then it comes to putting it all together and knowing which
> component caused which occurrence of what.
> 
> I know there is a bunch of tutorials out there, but they are all of
> the style "if 1 + 1 = 2, what is the molecular constitution of binary
> star system XT394-MY if the two suns collapse at the neocortex of the
> meridian divesture?" In other words, WHAT???
> 
> What explanations can you offer or what tutorials can you point me
> to? Thanks in advance for expanding my mind with your knowledge!
> 
> Best regards,
> 
> JIQ

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