Verify string s7 1200

Hi!

I have a string with 10 letters. I can edit the string in my HMI.
Now I want my plc to get a signal if there is something written in my string, and not a signal when the string is empty. Somekind of compare, I was thinking that I could compare the length byte of the string, but it couldn't be done. How do I do it?

Hello

For Step7 in the standart library, under IEC functions there is a standart function FC38 STRNG_I which returns 0 for empty strings and a non-zero value for non-empty strings. I think this is what you are looking for. I dont have TIA installed on my computer right now so I can't check, please check if there are any IEC standart functions in TIA.

String length

Have you tried the LEN instruction?

- Extended instructions
- String + Char
- LEN

I wiull try your tips on monday! I'll keep you updated. Thanks!