AB MSG instruction help

[Stickman47]

I have a project to add a Micrologix 1200 to an existing SLC 5/03. I have created a DH485 network using a 1747-AIC for the SLC end, and an AIC+ for the ML 1200 end. There is also a PV600 connected at the SLC end. The SLC I/O is 120vac and the ML1200 is 24VDC. At the initial installation ice cube relays were installed in the SLC cabinet to bring inputs from the ML1200 to the SLC. My boss wants these relays eliminated, and the signals put on the network. I have read many posts about the MSG instruction, and have read AB's documentation until my eyes bleed but I don't seem to be getting it right. Can anyone walk me through an example that I can use to get my mind around this ?

 

[jde777]

this should help

http://rockwellautomation.custhelp....ion.cfg/php/enduser/std_adp.php?p_faqid=17465

 

[ScottyUK]

One word of caution:

Are any of the hardwired signals carrying signals critical to safety, e.g. interlocking, overrides, etc? If they are then I would suggest caution before committing them to a PLC data link, although I would equally not expect them running on a general purpose PLC.

jde,

Thanks for the link

 

[Sparkylu952]

I would copy the output data file to an integer file (N9:0 for example)as a word, using the COP cammand. for example, a 16 channel ouput card would be O:1 (at the word level). This word represents the all 16 outputs, O:1/0, O:1/1, O:1/2, etc... You would COP O:0 to N9:0 for example. Use the MSG command to send the N9:0, over you communication link, to an integer file in the SLC, say N10:0 for example. Then, use the N10:0/0, n10:0/1, N9:0/2, ETC . . . bits that represent the inputs on the other PLC in your logic in place of the Inputs you are using now. Also, single click on a MSG command in the ladder file and push F1. I am a self taught programmer using the Help file. Good luck

 

[Sparkylu952]

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