Is there any option to avoid multiple duplicate alarms occurring for a minute.
active delay and
clear delay are what you're looking for.
clear delay in this case. Set it to 60 seconds, so when the alarm clears it can't reactivate in the next minute.
Should I have to update active delay as well?
Only if you need to. The active delay will make it so that alarms only trigger if their activation condition is true for more than a certain delay.
Mode: Above setpoint
Active delay: 30
Clear delay: 60
When the tag's value becomes higher than 3, nothing happens for 30 secons.
After 30 seconds, if the value is still above 3, the alarm triggers.
If the value went back below 3, then the alarm doesn't trigger.
When the value goes down below 3, the alarm is not clearer yet.
60 seconds later, if the value is still below 3, the alarm is clearer.
If the value went back above 3, then the alarm stays active.
Let's take an example case:
t = 0: value goes up to 5
t = 30: value is still 5, alarm becomes active
t = 40: value goes down to 2, alarm is still active
t = 80: value goes up to 6, alarm is still active
t = 100: value goes down to 1, alarm is still active
t = 160, value is still 1, alarm clears.
Instead of 2 activations of the alarm, we get only 1.
I have one doubt here.
I have configured an Alarm for Actual Speed based on "+" or "-" 10 rpm of Set Speed.
Here if set speed is 100 then the tolerance value will be in between 90 and 110.
if the value of the actual speed in 111 at 3:00 PM then there will be an alarm triggered
and if again the value goes to 112.5 at 3.00.09 PM an alarm is triggered and goes on. Hence i have multiple alarms.(I have enabled auto acknowledge)
How can i have only one alarm when the value deviated at 3.00 PM only?
It shouldn't happen since you have
any change set to false.
Going from 111 to 112.5 shouldn't trigger a new alarm.
That pic doesn't tell me the value went from 95.1 to 95.2. It might have went to 90 in between, and thus cleared the alarm then retriggered it.
Which is why you have the possibility to set up a clear delay.
If the value DID go from 95.1 to 95.2 and the alarm retrigger without clearing first, you should contact support, because I don't think it's supposed to happen this way.
Alarms run off the realtime value, which can change more than gets recorded, depending on the history settings. Showing that chart is not definitive.
As Phil said, if you're recording every minute, but the data changed every 10 seconds, you missed 5 data points which could have been below your alarm setpoint, clearing the alarm, then above again, retriggering an alarm.