SLC500 MSG Instruction

[VillaBoy]

Can somebody please supply me with a code sample/info for SLC500/4 MSG Read/Write over DH+ that will auto recover after any sort of lock-up?
I thought I had it, but it fouled up today (PLC communicates with other SLC500/4's)

Thanks

[Allen Nelson]

You might try this link:

http://www.control.com/PLCArchive/DH-485_Comm.pdf

The code here is to sequence communications between 4 different PLCs (having only one MSG block active at a time. I'm not sure if that's what you want, but it does a good job of showing how to recover from comm failures.

[VillaBoy]

Thanks Allen.
My code was similar - found out later that the installation took a lightening strike last night and screwed up the processor. Now if only the site enginer had told me that in the first place......
Such is life I guess