Copying strings in rslogix500

[Matthias von Zorn]

Cant use a move command, so how does one move as string is rslogix 500. I cant seem to find and string related commands for copying.. I can compare em, annotate them, but not copy them?? Thanks in advance.

Matt

 

[bernie_carlton]

Use the Copy (COP) command giving the address for the source and destination. Make sure to put the pound sign (#) before each. The length is one (1) for each string to copy.

 

[Jack]

Just a thought, but could you use the String Extract (AEX) command? It doesn't look like it changes the source, has a destination, but is limited to 82 characters.

 

[Matthias von Zorn]

Yeap, thats it! Thanks. Havent used strings much in logix, but ive been forced into it this time around. Cool avatar jack. Back to the grind.

 

[93lt1]

The length is one (1) for each string to copy.

What is the limit?
I know that the length for the COP instruction is usually measured in 16 bit words. How does this work with the ST data type?

If the destination file type is 1 word per element, you can specify a maximum length of 128 words. If the destination is a timer file (3 words per timer), you can specify a maximum length of 42 elements (3 x 42 = 126). In this case 2 words would remain unused.

 

[bernie_carlton]

The setup of a ST (String) type file accepts up to 256 strings. Since the Copy command suggest a limit of 128 words and each string takes up 42 words I guess 3 strings is the limit. I've only moved one at a time so I really don't have any first hand information.

 

[Allen Nelson]

Int's and Str's

There are several ways to manipulate ST strings and I integers (or A ASCII) registers.

1) Use the COP command. If you want to build a string that's stored in N11:1 through N11:4 (eight characters, from an ASCII read instruction from a device connected to channel 0), then first MOV 8 into N11:0. Then when you do the instruction COP #N11:0 #ST12:0 1, the first element of the ST data block, the length, will be what you want (that is, 8 characters), and you will get what you want and nothing else. COP's without the pre-defined length get very strange, since the first ASCII character pair wind up in the .LEN.

2) You can manipulate each ASCII pair individually as if it were an integer. Just as the address ST12:0.LEN references the length. ST12:0.DATA[0] references the first TWO characters in the string. .DATA[1] are the third and fourth characters, etc. A MOV N11:1 ST12:0.DATA[0] would replace the first two characters in ST12:0 with the data in N11:0.