Temperature control with AD prod 2000

[just the cowboy]

I am tring to bring the temperature control of some electric heaters into a AD Prod 2000 PLC and need some help. The current temperature controlers use a PID loop to keep temperature constant. They have a discrete output firing a SSR.

Is there a instruction in the PLC to do this? Both the PID and Ramp instructions use a analog output, or will I have to build some back end logic off of the PID.

 

[gbeaker]

A common way is to use the 0-100% output signal to compare against a 100ms timer. Anytime the output signal is greater than then current timer count, turn on the output.

If the PID output is 60%, then the output would be on from 0-60ms and off from 61-100ms.

 

[just the cowboy]

Thanks

A common way is to use the 0-100% output signal to compare against a 100ms timer. Anytime the output signal is greater than then current timer count, turn on the output.

If the PID output is 60%, then the output would be on from 0-60ms and off from 61-100ms.

Thats what I thought I would have to do, old school.
Thanks

 

[cjh]

In the software (Productivity Suite), if you look at the help file for the PID instruction, at the bottom there is an explanation and code example for doing "Time-Proportioning Control". This should do what you are looking for.

 

[just the cowboy]

Thanks for example

In the software (Productivity Suite), if you look at the help file for the PID instruction, at the bottom there is an explanation and code example for doing "Time-Proportioning Control". This should do what you are looking for.

Thanks for the example I like the idea of error output as timer preset