Resetting a tag in Structured Text in Logix Designer

[FelipeGarcia]

Hey!

I'm looking for a way to reset a tag when the routine that sets the tag is disabled.

For example:

Routine 1 has the following

If Tag1 then
Tag2 := 1;
Else
Tag2 := 0;
End_if;

And while Routine 1 was enabled, Tag1 was 1 (true) so Tag2 was also 1 (true). However, if Routine 1 is disabled, Tag2 stays 1 (true).

Any way of resetting Tag2 while Routine 1 is disabled without explicitly resetting it outside of Routine 1? Am I missing something?

Thanks!

 

[daba]

Yes, you are missing the fact that the controller responds to your demands.

As to your problem, I would do it explicitly if the routine is not being called ....

 

[FelipeGarcia]

Hey!

Thank you for your answer!

I understand that the controller responds according to what it was demanded to do. But it's a good reminder for everybody, including myself...

I also understand that explicitly reset the tag outside the routine is an option. However, my question was different. And maybe not clear enough.

I was wondering if there is a way to set up controller parameters to "operate" for structured text the same way as it does for sequential function chart when the Last Scan of Active Step -> Automatic reset is selected and there is brackets around the assignment symbol for a tag in a nested SFC routine.

Thanks!

 

[drbitboy]

I think daba answered this on another thread recently: call Routine_1 on scans when enabling bit is EITHER {1} OR {has a 0-to-1 transition (i.e. a falling edge)}.


I realize that is not exactly what is being asked.

 

[daba]

I think daba answered this on another thread recently: call Routine_1 on scans when enabling bit is EITHER {1} OR {has a 0-to-1 transition (i.e. a falling edge)}.

Your memory must be better than mine if I did !

And I've highlighted your typo : 1-to-0 transition, although tbf you did say "falling edge".

 

[drbitboy]

Your memory must be better than mine if I did !

And I've highlighted your typo : 1-to-0 transition, although tbf you did say "falling edge".

Good catch: yes, it should be 1-to-0.


You don't remember? It was less than 2h ago: https://www.plctalk.net/qanda/showthread.php?p=875845#post875845

 

[daba]

Good catch: yes, it should be 1-to-0.


You don't remember? It was less than 2h ago: https://www.plctalk.net/qanda/showthread.php?p=875845#post875845

I goofed, I'll work out how someday....