Variable not generating alarm on AlarmGroup

darius-dan
2015-09-03
2015-09-04
  • darius-dan - 2015-09-03

    Hi.

    I have a simple Ladder program that has this:

    • "Low Flow Switch" forwarded by a "Pump on" status.
    • If both are true, after some time, it sets a "Low Flow alarm".
    • "Low Flow alarm" turns off the pump.
    • Now, as the pump is off, "Low Flow alarm" is also false.

    The problem is: "Low Flow alarm" is only true for a single scan, and it is not showing on the Alarm Table on the WebVisu. If I remove the "Pump on" status from the logic, for testing purposes, it works. Is there a minimum time the variable needs to remain true so AlarmGroup triggers its alarm?

     
  • TimvH

    TimvH - 2015-09-03

    Never tested this myself, but what you might check:
    - in the Task Configuration is a implicit call to the AlarmManager.Alarm_Prg.
    - the scan-time is 50ms (default for the Control Win)
    - Probably your program is called from the MainTask which is called every 20ms
    - If this is true, than you program has already set the alarm variable to false before the Alarm_Prg has seen is.

    Maybe by playing with these settings a little you can optimize it, but as mentioned, I am not sure so please let us know your results.
    Another solution could also be to extend the time this alarm bit is true with e.g. a TOF timer.

     
  • darius-dan - 2015-09-04

    TimvH hat geschrieben:
    Never tested this myself, but what you might check:
    - in the Task Configuration is a implicit call to the AlarmManager.Alarm_Prg.
    - the scan-time is 50ms (default for the Control Win)
    - Probably your program is called from the MainTask which is called every 20ms
    - If this is true, than you program has already set the alarm variable to false before the Alarm_Prg has seen is.
    Maybe by playing with these settings a little you can optimize it, but as mentioned, I am not sure so please let us know your results.
    Another solution could also be to extend the time this alarm bit is true with e.g. a TOF timer.

    YOU'RE RIGHT!

    I changed the alarm task to 20ms like the Main task and it triggered just fine. Thanks.

     

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