Issue with step.t in OpenPLC SFC OpenPLC Editor
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Junior Member 5 posts omayma Junior Member 5 posts
omayma
Hello,
I am working with OpenPLC Editor using SFC (Sequential Function Chart).
I have a step called "go_to_sensor" and a transition condition:
"go_to_sensor.t > t#5s"
My understanding is that this should trigger after the step has been active for 5 seconds.
However, the transition never becomes true, even when the step is active (green).
I also see messages like:
"PLC execution time is longer than requested PLC cyclic task interval"
Questions:
1) Is the syntax "step.t > T#5s" fully supported in OpenPLC SFC?
2) Is step.t equivalent to IEC 61131-3 step time?
3) Is there any official documentation for SFC behavior in OpenPLC Editor?
I am coming from Machine Expert / IEC SFC, and the behavior seems different.
Screenshots attached.
Thanks in advance.
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thiagoralves Admin  9,451 posts
thiagoralves
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omayma Junior Member 5 posts
omayma
Thank you for the clarification.
That matches exactly what I am experiencing.
In my case, step.X works correctly (the step becomes active/green),
but step.T (or step.t) never behaves as expected and the transition condition
"step.t > T#5s" never becomes true.
So it seems that, although step.X exists, the implicit step timer (step.T)
is either not implemented or not supported in OpenPLC SFC.
I will switch to using an explicit IEC timer (TON) inside a step action
and use TON.Q for the transition condition instead.
Thanks for confirming this behavior.
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