PLC-5 MESSAGE COMMAND

[Guest daskat]

Hey folks, I am attepting to send one word of data from one PLC to another PLC both on the same data hiway. every time I try I am told I have formatted the control block incorrectly. Both PLC's are online and I attempting to program while still online. Is this the soure of my problem? or do both programs require the command. the control block is just an interger file word as far as I can tell. shouldn't the setup block format this word? Thanks again for talking the time to read this TTFN DASKAT

[Ken Roach 194]

Only the PLC in which you are programming the MSG command needs an instruction to perform the message. In Classic PLC-5's, the MSG control block was a block of integer registers. In Enhanced PLC-5 controllers it is a special "MG" data element. Be absolutely sure you are not overlapping or re-using a data file for your message instruction that is used anywhere else in the control program. and last... post what you *have* tried.

[Ken Moore 23]

To expand on Ken's response. If you are trying to create a "new" address, you cannot create a memory allocation while the PLC is in run mode. To do so online, you must use an existing memory address.

[daskat 0]

Thanks for the help folks, I finially got it to work and have made the following observations. 1) The control block is at least 10 words long so don't have the control block in the same file as the words being transfered. 2) Yes this command can be programmed online using RSLogix 5. so again thanks and have a great day. TTFN THE KAT

[daskat 0]

PS You only have to use an MG file if you are transfering ASCII words thanks again THE KAT