BASIC module on SLC 500- basic program question

Hi all

I have a SLC 5/04 with a BAS module sending print data to a dot matrix printer. In the Basic program in this module, there are what possibly appears to be indirect addresses which are actually integers present in the PLC program. These integers change based on cycle recipes chosen by the operator. These addresses (at least that's what I think they are) are denoted with a "MO" followed by another number in brackets.
Please see the attachment to see what I am talking about.
What I want to do is add a new line of print referencing a new integer from the PLC. No problem adding another line to the code. Problem is, I dont what or where these MO things are. Also no idea what the CHR thing is. Any basic pros out there?
Also, how do I upload the modifed BAS file to the Basic module? I used to know this, back in the day....

CHR is a function that converts ASCII code to a character, so CHR(10) is a newline a.k.a. linefeed.


The MO references could be an array or a function, or it may be something special in the BASIC module of the PLC.


I have no idea how any of this worked; I would google the stffing out of it if I had to do this.

Thanks...and I remembered how to upload the file...HyperTerminal. Still lost with the MO thing...

It's been ages since I used a Basic module, but here's what it looks like to me, assuming you are using a 1746-BAS or 1746-BAS-T and not a third party module.

MO(x) appears to just be a Basic module variable array.

I'm not sure without seeing the rest of the code, but they could be copying up to 64 words and copying them to the MO(x) array in the Basic Module program.

Somewhere above the lines you shared should be a "CALL 56" to transfer data from the M0 file in the PLC code. The "PUSH" command above it sets the amount of words to transfer.

After that will be some type of CALL with a PUSH 100-163 before it adn a POP MO(x) after it.

In the PLC program there should be a copy to an #M0.Y.Z, where Y is the slot number and Z is the word.

These 2 manuals may help:
https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1746-rm001_-en-p.pdf
https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1747-rm001_-en-p.pdf

The M0 & M1 files exist in the SLC, these are used to transfer data from/to the Basic card so for example the print will print the text plus the data in the M register(s). It's been many years since I used one of these the M0/M1 files are used to transfer 64 words each I believe so these are the basic buffer memory.