Ok, so what do I do with the result? :) Does this give me my adjustment
value?  I am going to use a PWM to drive the servo with high and low
deadbands.  Could this PID value give me a # to increase or decrease my
pulse width for the servo driver?  The servo is driven by a possitive
pulse and the position varies with the PW (1-2ms range)

Thanks for the help.
Jody Gallant

-----Original Message-----
From: Dennis Merrill [mailto:merrill@NICOLET.COM]
Sent: Monday, January 25, 1999 12:44 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: PID control & new member


If you are trying to implement a PID controller on a PIC, this is pretty
easy.
First, you need to calculate your threee constants, Kp,Ki,and Kd.

P = Kp * current value
I = Ki * Sum of all previous values
D = Kd * ( this value - last value )

PID = P + I + D

At least, this is how you do a digital PID. You can also buy PID chips
that
work in the same fashion.

At 10:29 AM 1/25/99 -0400, you wrote:
>Hi, My name is Jody Gallant. I am a systems analyst for Tech Sea
>Corporation Ltd. in New Brunswick Canada. I am quite new to PIC's but
am
>trying to learn as much as I can.  I am trying to design a circuit to
>control the wastegate for the turbocharger on my car.  There is nothing
>wrong with the one that is built into the ECU but I would like to have
>some manual control over this function.
>
>I have most of the hardware details worked out, but am trying to come
up
>with a good tuning algorithm for this and would welcome any help. what
I
>need to do is control an R/C servo (PWM) based on the current MAP
>(manifold absolute pressure) and the current Boost preset.  I have been
>doing a lot of studying on PID loops which might be the best answer,
>however I have not been able to come across anything directly related
to
>PIC 's.
>
>Thanks in advance for any advice.
>
>Jody Gallant
>
>
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Dennis Merrill, BSEE         work: merrill@nicolet.com
 Firmware Engineer            home: merrill@ieee.org
 Embedded Systems Group
 Nicolet Instrument Corp.    phone: 608.276.6136

 web: www.geocities.com/ResearchTriangle/5256
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