Codesys - Cycle Time and Jitter

2021-03-18T14:37:24.820000Z

Okay, I'll have a look and see, thanks.

Codesys - Cycle Time and Jitter

2021-03-17T07:42:34.246000Z

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It's very suited for identifying the root cause of your timing issue's!

You can always run a month demo for free ;-)

Codesys - Cycle Time and Jitter

2021-03-16T15:40:37.456000Z

I have an issue with on of my programs, the cycle time seems to be extremely long.

Based on the task configuration:

Last Cycle Time (us) = 680000 - 720000
Average Cycle Time (us) = 117920 - but constantly climbs the longer the program runs
Max Cycle Time (us) = 807659

Jitter (us) = 806802

I ran the PLC load average in the PLC Shell command and it's only showing 49%.

I set up timers and noted one PRG was taking quite a bit more time:

Task End Time PRG Start Time Difference
Time 1 5168987211 5168987174 37
Time 2 5168987212 5168987174 38
Time 3 5168987218 5168987174 44
Time 4 5168987267 5168987174 93
Time 5 5168987275 5168987174 101
Time 6 5169607023 5168987174 619849
Time 7 5168986684 5168987174 -490

I comment out that PRG in the code and the times drop drastically:

Last Cycle Time (us) = 78000 - 82000
Average Cycle Time (us) = 17000 - but constantly climbs the longer the program runs
Max Cycle Time (us) = 156104

Jitter (us) = 155213

However my PLC load actually increased to 69%.

The program is taking data points and writing them to a file on a USB, using the CAA File (3.5.12.0) library. Is there a chance it's taking so long because of writing to the USB directly? Should I look to save directly to the HMI/PLC and then transfer to the USB after saving all the required data?

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