MOV with a STxx:xx File????

[tech-1452]

I am using a SLC 5/04 with a AST3301 Proface touchscreen. I am using 500 software. I have recipes stored in the Nxx:x file. I have names of the recipes stored in a STxx:xx file. Is there a way to MOV with a STxx:xx file? I have temporary running places in the STxx:xx file that I wish to temporary store the running recipe name so that I can display it on the touchscreen.

 

[bernie_carlton]

You use COPy to move a string from one place to another. You cannot use indirect references for the string though.

 

[OkiePC]

. . . You cannot use indirect references for the string though.

Bernie, can you clarify that last sentence? Did you mean indirection in the HMI?

 

[TConnolly]

The reason you can't use a MOV is because it operates on single words only and a string is 42 words long (82 chars (byte) + .LEN word). Use the COP instruction with a length of 1. COP uses element length, and even though a string is 42 words, it is still 1 element.

Another way to move single strings is using AEX. The reason I suggested AEX is that RSLogix 500 SLC instruction help states that you can use indirect addressing with this instruction.

AEX ST19:[N7:0] 1 82 ST20:0

This extracts the string at ST19:[N7:0], beginning at char 1 through char 82. If the string is less than 82 chars long then only the chars up to ST19:[N7:0].LEN are extracted.

 

[bernie_carlton]

Alaric covered it. COP won't let you use the indirect (eg [N7:0]). I never tried the AEX as a workaround. Good tip.

 

[tech-1452]

Thanks guys. That really helped out a bunch.

 

[bernie_carlton]

Just as an update, the AEX allows indirect in the source string address but not in the destination string address. For my recipe functions I need to use it both ways. Too bad.