Okay, so I'm one of the new guys to the PLC world - I do have programming experience but I am quickly finding out how little I actually know.
I recently had a project handed to me that has me confused - I'll try to summarize for the ADD crowd:
We have an error routine that should scan through several inputs. If a condition is met, the program should dump out a hex value to a database table which is later read by our software. The software then puts a message on the screen with the error code. Simple enough - no rocket surgery involved so far.
So far we have been able to confirm that the software is getting into the system and reading the right table, but it's not getting any data out, even when we force an error condition.
During my troubleshooting, I noticed something odd - there are two symbols that have weird data types. I'm used to seeing hex, boolean, etc. but these two have data types of "DB 1" and "FC 84" that match their addresses. (See screenshots below...)
Thinking I had stumbled onto the problem, I tried to update these addresses to "BOOL" or "HEX" but the Siemens program throws an error and tells me that it's not a valid data type for this address.
I've been F1'ing through the help files to try to figure out how to change these, but so far it seems that there is something preventing me from saying "Allow address DB 1 to accept HEX data types" or "Allow address FC 84 to accept BOOL data types." They seem to be stuck somewhere.
My question is two-fold at this point:
TIA
The "Edit Symbols" window for this rung:
I recently had a project handed to me that has me confused - I'll try to summarize for the ADD crowd:
We have an error routine that should scan through several inputs. If a condition is met, the program should dump out a hex value to a database table which is later read by our software. The software then puts a message on the screen with the error code. Simple enough - no rocket surgery involved so far.
So far we have been able to confirm that the software is getting into the system and reading the right table, but it's not getting any data out, even when we force an error condition.
During my troubleshooting, I noticed something odd - there are two symbols that have weird data types. I'm used to seeing hex, boolean, etc. but these two have data types of "DB 1" and "FC 84" that match their addresses. (See screenshots below...)
Thinking I had stumbled onto the problem, I tried to update these addresses to "BOOL" or "HEX" but the Siemens program throws an error and tells me that it's not a valid data type for this address.
I've been F1'ing through the help files to try to figure out how to change these, but so far it seems that there is something preventing me from saying "Allow address DB 1 to accept HEX data types" or "Allow address FC 84 to accept BOOL data types." They seem to be stuck somewhere.
My question is two-fold at this point:
- Is it possible to update these addresses at all? (I know that FC84 is a system block and is protected, but I fear that something has corrupted the settings on it...)
- If it IS possible to update these, how the heck do I go about doing it? I have tried going into the symbols table and changing them there, but with no luck...
TIA
Screenshots:
The code
The "Edit Symbols" window for this rung: