S7 - Get DB symbol as string via instruction

Hi Chaps

I am wondering if there is an instruction that will allow me to get the symbolic name of a db if I know the number ?? It would help me so much

Thanks for any replys

SCL if possible

I dont't think this is possible. The symbols exist only in your offline project, not in the PLC, so this info can't be accessed at runtime.
What are you trying to achieve anyway?

My company have a plc code standard (not easily changed), the standard is for a conveyor system. lots of conveyor beds each using a set udt/db which is heavily integrated into a concept and not easily changed (this does not contain the conveyor bed number). I want to get error and availability data for each bed on systems that we have already implemented. so I have written a nice little bit of code that will get this information for me from the said DB's (using for loops to make it faster). the problem is linking the datablock to the conveyor bed position. I am currently handballing the db number in and associating it with the position, then running the loops. I would like to try and use the symbolic info to get the position number that is associated with the db. Hope that this makes sense

wimpiesplc , What you have said makes sense.... hmmmm shame

I will note that what wimpiesplc said is true for S7-300/400 PLCs, but not necesarily for the newer 1200/1500 systems. The newer PLCs do store the symbol names, and this information can be accessed by instructions such as "GetSymbolPath".

mk42 - Thank you . unfortunately it is a 400cpu

I do think you can get DB number, might that work for you?

You could set up another DB that contains the DB numbers and the associated symbol names as strings. Your code would have to search for a matching DB number and copy the string for you to use in your program. You would have to populate the DB manually of course.

mk42 said:

I will note that what wimpiesplc said is true for S7-300/400 PLCs, but not necesarily for the newer 1200/1500 systems. The newer PLCs do store the symbol names, and this information can be accessed by instructions such as "GetSymbolPath".

Click to expand...

I knew it stored the symbols, and the project, but was under the impression you couldn't access them. But learned a new thing about GetSymbolPath, thanks. It appears it doesn't work on a 1200 though.
I can get a string like 'DB_name.indexed[4]' So I guess you can extract this '4' from it and use it further