Integerator

[Mark Romans]

Proportional Integral Derivative Controllers and yes GM does use pid.  It's
labelled as such in the code on the 89 TPI 165 ecm.  Just don't aske me how
to tune it.
Mark
-----Original Message-----
From: Roger Heflin <rah at horizon.hit.net>
To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
Date: Wednesday, November 03, 1999 9:38 AM
Subject: Re: Integerator


>
>
>On Wed, 3 Nov 1999, CSH-HQ wrote:
>
>> OK, then the short term corrections are integerator, and not stored,
right?.
>> They are a simple feed back response to what the ecm memcal want for
mixture.
>> Do the gm ecms actually use a PID, or just a dampened feedback loop?.
>> Is ther much difference from feedback to PID?.
>> Grumpy
>>
>>
>The integrators are not stored long term, once you leavel that BLM
>cell the integratros are reset to 0( 128).   But if the integrators
>are greateer that +-8 (<120 or >136) on my car that makes the BLM
>cell be adjusted, but when the BLM is adjusted the integrator is not
>adjusted on a stock car.  2 integrators points are equal to 1 BLM
>point.  On my car I modifed the code so that when the BLM is adjusted
>because of the integrator, the integrator is also adjusted to maintain
>constant mixture, this caused my car to not osciallate so much on the
>fuel mixture.   I belive the oscillation was mostly because the VE
>were so far off from all of the modifications I have done to it.
>
>What exactly is a PID?  If I remember control systems right a feedback
>loop is a standard control setup, so my guess would be that a feedback
>loop is a PID, and standard controls systems stuff dones usually
>dampen the feedback loop to prevent rapid osicllations.
>
> Roger
>