I am trying to setup some alarming where the alarm triggers when sensor value is outside a normal range and will delay clearing for X amount of time or when the latched alarm bit in the PLC is cleared. I got this to work with the high high alarm, but when I apply exactly the same settings to the low low alarm it doesn’t work. The low low alarm immediately clears once the sensor returns to a value above the low low setpoint. The screenshots below show how the high high and the low low alarms are setup. I can’t figure out why it works with the HH and not with the LL, to me they look like they are setup identically and should function the same. Can anyone see a reason why the LL alarm clears immediately? I am 100% sure that the Analyzer-LL tag latches in and stays at a value of 1 until the alarm reset command is given.
Have you confirmed that {[.]Analyzer-LL} is a non-zero value for the instance you are testing on?
I have, its definitely a 1 when the alarm occurs
Nevermind, just realized that is a tag path and not a parameter.
I think I figured out the problem, it was related to the timing between the alarm being triggered and the Analyzer-LL tag being read from the PLC. The alarm was being triggered in Ignition at the same time the Analyzer-LL tag was being set in the PLC. But there is a delay in Ignition reading that boolean value from the PLC, so the alarm was clearing before it had a chance to update the tag and do the clear delay calculation.