C Program for PID Controller

[Eugenio Acevedo]

Hallo!
I am looking for a C Program that works like a PID Controller for the
microcontroller 80167. It is for educational purpose.
Do you know where could I find information or examples?

[Stijn Vanorbeek]

What would you like to c ontrol by PID : motion ? Temperature ?

There is a good aplication note at www.microchip.com explaining how to
program PID motioncontrol in C, that one was helpfull for me to
understand how PID is implemented in C.

[Steve Holle]

On Wed, 28 Jun 2000 07:05:03 GMT, st...@easynet.be (Stijn Vanorbeek)
wrote:
Circuit Cellar Inc. had a series of articles some time ago about
programming a micro to do PID to levitate a steel ball using electro
magnets. check out www.circuitcellar.com

[marius]

What is the exact appnote, I tried a search but there's nothing with
PID in the title or as keyword.

Stijn Vanorbeek wrote in message
<3959a30d...@news.easynet.be>...

[Zoran Tomicic]

In article <39594E1C...@iei.tu-clausthal.de>,
ace...@iei.tu-clausthal.de says...

>
>Hallo!
>I am looking for a C Program that works like a PID Controller for the
>microcontroller 80167. It is for educational purpose.
>Do you know where could I find information or examples?
>

Here is the simple PID code.

/* pid.h */

typedef struct
{
float Kp; // proportional gain
float Ti; // integral time
float Ts; // sampling period
float Integral; // old integration value
float High; // high limit
float Low; // low limit
float Td; // diff. time
float Tf; // first order filter constant for D component
float DifOld; // old D value
float ErrOld; // old error value
} PI_STRUC;

int PidControl (PI_STRUC* pid, int Error);

/* pid.c */

int PidControl (PI_STRUC* pid, int Error)
{
float e,i,y,d,k;

e = (float) Error;

i = pid -> Integral;

i = i + (pid->Ts * e) / pid->Ti;

if (i > pid->High)
i = pid -> High;

else if (i < pid->Low)
i = pid -> Low;

pid -> Integral = i;

if (pid -> Td)
{
k = pid -> Tf + pid -> Ts;

d = ((e - pid -> ErrOld)*pid -> Td + pid -> Tf * pid -> DifOld) /
(pid -> Tf + pid -> Ts);

if (d > pid -> High)
d = pid -> High;

else if (d < - pid -> High)
d = - pid -> High;

pid -> ErrOld = e;
pid -> DifOld = d;

y = i + pid->Kp*e + d;
}

else
y = i + pid->Kp*e;

if (y > pid->High)
y = pid -> High;

else if (y < pid->Low)
y = pid -> Low;

return (int) y;
}

Regards
Zoran
Microtrol Pty Ltd
www.microtrol.com.au

[Stijn Vanorbeek]

You should look for AN531 and AN532 (motor control)

On Thu, 29 Jun 2000 15:33:30 -0400, "marius" <mari...@bellsouth.net>
wrote:

>What is the exact appnote, I tried a search but there's nothing with
>PID in the title or as keyword.
>
>Stijn Vanorbeek wrote in message
><3959a30d...@news.easynet.be>...
>>What would you like to c ontrol by PID : motion ? Temperature ?
>>
>>There is a good aplication note at www.microchip.com explaining how
>to
>>program PID motioncontrol in C, that one was helpfull for me to
>>understand how PID is implemented in C.
>>
>>On Wed, 28 Jun 2000 03:00:12 +0200, Eugenio Acevedo
>><ace...@iei.tu-clausthal.de> wrote:
>>

[Patrick Smout]

Read the book

PID Controllers: Theory, Design and Tuning

K. Äström and T. Hägglund - ISBN 1-55617-516-7

It reveals the theory behind and the implementation of modern PID control
systems. Coding is much easier once you understand the theory.

The Microchip AN531/AN532 DC motor control application uses a basic
implementation of a PID controller. Despite the fact that it is a fine AN,
it is not a good example for implementing a PID controller in a
microcontroller. There are a lot a of real-world topics that are not covered
by the example.

Best regards,

Patrick Smout

Stijn Vanorbeek <st...@easynet.be> schreef in berichtnieuws
395c3cd...@news.easynet.be...