s7 Graph - timer

cjd1965

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Hi I am playing about with S7 graph.

If I have a problem where i need to know if the cycle time of 3 consequtive steps exceeds a time...

basically in step 2 run a timer, and leave it running in step 3 and step 4. If the timer elapses, alarm and goto step 1

II cant see within graph how to use 3 steps to run the same timer. Am i going to have to do this 'outside' of the graph?
 
S7-Graph

Hi,

My opinion is that I would Set a bit in Step 2 and Reset it in Step 5. This bit can be used to run an on_delay outside the graph, if the timer exceeds, you can initialise the Graph on the outside of the graph FB... This will work.

Kind regards,
Combo





cjd1965 said:
Hi I am playing about with S7 graph.

If I have a problem where i need to know if the cycle time of 3 consequtive steps exceeds a time...

basically in step 2 run a timer, and leave it running in step 3 and step 4. If the timer elapses, alarm and goto step 1

II cant see within graph how to use 3 steps to run the same timer. Am i going to have to do this 'outside' of the graph?
Click to expand...
 
Last edited:
I'm not a Graph user (but SFC). But maybe this can work:
Make a parallel branch over the steps you want to monitor. Let it end in an alternative branch.
If this parallel branch times out first, run the alternative with restart. If the 3-steps times out first, go on.

... Hmm. It sounded both complex and stupid... I'll log off and walk the dog.:)

Kalle
 
hmm

If you want to run in parallel braches in the graph, then you will have parallel steps. If you jump back, the parallel steps may still be active. You should do init then I think instead of jumping back. The problem is that you have several steps, you should run a parallel step over each step with a monitoring time I think... Didn't test it, but I still think outside the graph is easier.

Kind regards,
Combo


KalleOlsen said:
I'm not a Graph user (but SFC). But maybe this can work:
Make a parallel branch over the steps you want to monitor. Let it end in an alternative branch.
If this parallel branch times out first, run the alternative with restart. If the 3-steps times out first, go on.

... Hmm. It sounded both complex and stupid... I'll log off and walk the dog.:)

Kalle
Click to expand...
 
Hi all
thanks for replies. If the timer expires the design intent is to return to step 1 (reset) so if i do the parralel branch idea and then enable (N) a db bit to reset the graph on the input (SQ_OFF?) would this work?
 
k

Should work.

cjd1965 said:
Hi all
thanks for replies. If the timer expires the design intent is to return to step 1 (reset) so if i do the parralel branch idea and then enable (N) a db bit to reset the graph on the input (SQ_OFF?) would this work?
Click to expand...
 

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