Two applications running on a PLC

Hi everyone,

It's the first time I'm using this forum to search for answers and I quite feel it's going to be worth the efort. So, let's go to it !

I'm going to develop an application which will run on an Allen Bradley SLC 5/03. It's worth saying that this PLC already has an application running but the new application I'm going to develop and the old are mutually exclusive, i.e, when one is running the other won't be .

I'm considering the idea of creating a subroutine which will take care of this new application and insert it in the actual code of the PLC.

Is it the best solution ?

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Yes, two seperate subroutines called from the main ladder file in a mutually exclusive manner seems good.

take care

You must remember that when you stop calling one program and start to call the other that any outputs etc will be left in their last state.

I agree. That is the way I do it. The equipment types I program have several mutually exclusive applications that I have written as subroutines.

One word of caution: If you are using any latch/unlatch coils in either subroutine, make sure you drive them to the proper state before exiting the working subroutine.

Steve.