Peer to Peer MSG CLogix to SLC (Help)

[mugs 0]

I am working on a "duplicate" of an existing system, however the new work cell will use a Control Logix in place of a PLC/5. One of the nodes in the cell has an SLC504 and was set up to communicate via peer to peer MSG over DH+. I have a DH+/RIO card on the Logix Rack and the ControlLogix code has a MSG Write (SLC Typed Write), which I think will work fine, but on the other side, in the SLC, I have a MSG Write and MSG Read with the target device as a PLC5. Anyone know if this will work? The only options for the device type are PLC5, Modbus, and 485CIF.

[Allen Tuh 1]

Yes MSG Write and MSG Read will work fine between CLX and PLC5. Just use the PLC5 Typed Write or Read in CLX coding.

[pelly09 0]

i may be wrong and i'm sure i will be corrected if i am but i don't believe you can initiate messages between SLC and Controllogix from the SLC, only from the Logix. The messages will have to be set up in your new PLC. I had the same problem a couple of years ago when we replaced a PLC-5 with a Controllogix, i removed the MSG Read from the SLC and put in a MSG Write in the Logix, this was connected by DH+ and all is well. Hope this helps Steve

[Ken Roach 194]

Data is exchanged between ControlLogix and PLC/SLC using PLC/SLC addressing, like "N10:1" and "B3:1/0". The PLC and SLC platforms know nothing about the Logix tag-based addressing mechanism. When the MSG instruction is in the ControlLogix, a PLC-5 or SLC-5/04 work the same on DH+. The MSG instruction goes as far as the 1756-DHRIO itself and then you configure which channel and which node to which the DHRIO module will execute the Message transaction. When the MSG instruction is in the SLC, things get a little bit more complex (but not impossible). First, the ControlLogix has to know what Tags or Tag Arrays to use when it gets a request to read or write an SLC/PLC style address. This is configured in Logic -> Map PLC/SLC Messages inside RSLogix 5000. You set up one or more array tags with INT[x] datatype in ControlLogix and map them to a PLC/SLC file number. When the ControlLogix receives a request for "N7:5", it will look in the mapped array tag "SLC_Integers[7]" for the data value (if that's what you named the tag). Integer, Float, and Boolean data are the only datatypes that can be mapped this way. PLC/SLC Mapping works perfectly over the Channel 0 serial port. But when you want to send the message to the ControlLogix over DH+ and the 1756-DHRIO, the DHRIO has to know what Slot Number the ControlLogix is in. The default is Slot 0; if you have never configured a DHRIO for Default Slot and the 1756 controller is in Slot 0, then you're fine. If the controller is not in Slot 0 or you need to do more routing, you'll have to read up on the DHRIO Remote Link routing functions. The ControlLogix General Instruction Set Reference manual (1756-UM003) has a very good and very thorough chapter on the MSG instruction.