micro PID

Can anyone help me I wish to set up a PID to control temp on a machine using a Telemecanique miro PLC, but I don't understand how to programe the operator block.
Cheers

What area is giving you problems?

What software package do you have? PID functions are part of the PL7 Junior and Pro packages.

Finding the block? Shift F3, Right Mouse Button, select Enter Call for Function, scroll down and select PID.

Format of the PID block? Have you read the manual "TLXDS57PL743E,PL7 Junior/Pro - Premium PLC Applications - Analog, Regulation, PID, Weighting (EN)" at: http://www.modicon.com/85256AE8006D789F/all/42B296DFE035949B85256BB20042B98F/$File/35005130_K01_007_00.pdf

I'm useing PL7 Pro. I can get the block up but not realy sure of what to put in it. This was my last attemp.

PID('TEMP','Degrees'.%MW0,%MW10,%MW1:1)

The system is OK with this so I think the syntax is OK, but it does nothing.

The first part I understand but is %MW0 my PV or actual Value inputed from the analog card?
Is the %MW10 an output? %MW10 is auto something or other I don't know were this value comes from and %MW1.1 is a parameter or is it the Set Point value from the Magilis screen. its all muddy water to me I have read the manual but I'm afraid I can't get my head around this one. i have also had my local Telemecanique rep in who is normally very good but he has never done PID set up so was unable to help.
Any help you can give me would be great, I think were being a little thick in the head over this one.

Cheers

Dave

Your syntax is wrong, you are missing the AUTO pointer and your PARA table is too small. The correct syntax is: PID(TAG, UNIT, PV, OUT, AUTO, PARA).

PV - the process variable (what you are measuring), it can be from an analog input (%IWxy.i) or an internal register (%MWi), yours appears to be %MW0
OUT - the controlled output (what you want), it can be an analog output (%QWxy.i) or an internal register (%MWi), yours appears to be %MW10
AUTO - selects automatic or manual mode, it can be a real I/O (%Ixy.i or %Qxy.i) or an internal bit (%Mi), yours appears to be missing
PARA - a table of 43 consecutive registers, the first 15 or so are the PID parameters (i.e. gain, integral time, sampling period) the remaining ones are used by the function itself, yours appears to be %MW1:1 which is too small (%MW1:43 would be correct except it would then conflict with your output at %MW10)

Look at the help menu index, under PID Functions (Micro specific) for more information on the parameters table.

PID in PL7 Pro

Dear Jim,
I'm facing the same problem eventhough the parameters setting seem to be correct. Appreciate if you could help.

ahd,

I have not reviewed all of your program. The first thing I noticed is the location of the PID operation in your program.

Your Master program is set to be a cyclical (normal) scan. For the PID to function correctly it needs a periodic (fixed) scan.

My suggestion is to move the PID operation to a new Fast (periodic) task, instead however you can change your Master task to be periodic.