RSL5k - Multiple message instructions

[Ken Wiegers]

Hi,
I'm using message instructions for the first time and I have a very fundamental question that I'm surprised I could not answer with a google search.

Is it OK to use a single, identical, MSG instruction in multiple places in a program, with each use being triggered by different conditions. I know this would be OK with something like a counter, and not OK with an OTE, but I'm not sure where MSG stands.

Thank you.

 

[kjs1230]

it may be difficult to troubleshoot having multiple instances of the same MSG instuction... I don't know a technical reason why you can't do it...In my use of the msg instruction I haven't done that, I've used seperate Msg instruction tags for each instance

 

[beethoven_ii]

I would suspect this wouldn't work as the status bits would being being set or not all over your program with the possibility of it being set to run more than once at the same time. Why not set a bit in each area of your program and use any of these bits on a single rung to trigger your message instruction?

Regards,

Barry

 

[TConnolly]

I wouldn't do it for MSG tags. Messages are queued, the scan doesn't stop and wait for the message to complete before moving on to the next instruction and status bits are not necessarily updated synchronously with the PLC scan. I'd create a new message tag for each message.

 

[harryting]

Even if you can, you shouldn't.

i can't even think of any scenario where that would be required.

 

[Ken Wiegers]

I've changed it to what beethoven suggested, it sounds much better than what I was doing.

Thank you all.