Controllogix 1756-CNB/E MSG To 1746-SCNR

[p_logix]

Hello all,

I'm am trying to figure out how a message initiated from a controllogix processor writes to a SLC 5/04 using control net.
Reading the example below (Which is a PLC5, only example I could find) I cannot see how N7:10 is mapped to #M0:1.700.

I can see we are initiating a message from source N7:0 to destination N7:10.

However they suggest to use a COP to grab the data from the #M0:1.700 file then place the data in a N11 file.

Where does the N7:10 come in to play? Is this a data table in the scanner module itself?

Is the mapping done in Rs networks?

Any help would be greatly appreciated.




The following example illustrates how a PLC-5 ladder program can
read or write the 1747-SCNR Local Database using the MSG
instruction. The steps in this process correspond to the steps in the
illustrations.
1.
The ladder programmer inserts a MSG instruction into the ladder
program.
2.
This message instruction sends
five words from the PLC-5 N7
data file, starting at offset 0, to remote 1747-SCNR Local
Database file offset 10 (N7:10). The destination node is 22.
3.
The PLC-5 processor is put in
to RUN mode. Then the PLC-5
processor opens an unscheduled connection to the 1747-SCNR
module and messages are exchanged.
4.
The SLC 500 ladder program reads 20 words of 1747-SCNR Local
Database in slot 0 offset 700: #M0:1.700.
5.
Elements from the PLC-5 N7 file are available in the SLC 500 N11
file, starting at address N11:10.

 

[Ken Roach]

Where does the N7:10 come in to play? Is this a data table in the scanner module itself?

You've got it. The 1747-SCNR maintains a "Local Database" in its M-file that emulates a PLC-5 Data Table. This is called the "Unscheduled Data Server" and is one of the least-well-known features of the module, and is described in Appendix A of the User Manual, which is where I presume you got that example.

You would probably use messaging to the Assembly Object from ControlLogix, instead of using the Local Database and PCCC style (N7:x) messaging like you do with a PLC-5C15.

Connectivity between a ControlLogix and the 1747-SCNR is complex at best, a stew of Produced/Consumed and I/O objects and PCCC messaging and M-Files. I haven't gotten into it in detail in at least six years.

Are you trying to troubleshoot an existing system or add a feature to one ?

 

[p_logix]

Thanks Ken, We are actually going to send data through an existing message that's already transferring some data. It looks like we have some words that are unused. We need to send a MVAR reading to a loadshed processor.

In the posted example does the fact that they specify N7:10 mean were actually dealing with #M0:1.710?????