Finding a DB bit in S7

Matchu04

Lifetime Supporting Member
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Join Date
Mar 2013
Location
Northampton
Posts
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Good afternoon...

Im hoping that someone will point out something that I am obviously missing. I am trying to find part of a program that controlS a number of bits within a DB.

Basically there is a fc that maps the actual I/O with a db bit but trying to find where it is controlled. It is driving me mad. I have already tried search for a word or byte within 'go to' but no joy.. Please help

1.jpg 2.jpg
 
Siemens does not have a find all from a tag table like AB. (V5.5 that is). Open up any FC, right click on a input, press "go to", then type in DBxx.DBX76.0.
You did not have the Data block number so I put in the 2 small "x's" So if its in data block 22, byte 76 bit 0. You would type in
DB22.DBX76.0

The DBX defines its a bit.


Hope this helps
 
This is my point, it does not show anything for db1702.dbx80.0 hence why i tried db1702.dbw80 etc etc but still no joy... in one of my photos it shows the pointer address i.e. p#db1702.dbx80.0

3.GIF
 
Last edited:
it won't be easy to find the use of that bit. it can be bit, or part of byte, word or dword. it does not even have to start at 80 as someone may have created some dword with 78 and wants to address specific bit in that dword
 
So going forward what is the best way to diagnose this as I can normally find my way with indirect addressing but this has thrown a massive spanner in the works
 
Generate source code for all the FCs/FBs and then search for the variable name in the resultant source code.
 
Then double click on the "all" file in the source folder. search the text file for the relevant variable name from the UDT

src4.JPG
 
If you post small snippets from your project we will be here forever. Copy the blocks into a library, archive it and post the code.
 

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