Alarm reiusses immediately due to dynamic analog input


#1

Hi All,

I’m setting up a basic alarm off of 4-20mA signals through an analog input module and I’m running into trouble with the alarm reissuing immediately after it is acknowledged. I adjusted the Re-Alarm Time with no effect. I finally realized it has to do with the input not being static. If I change the input to one of my flowmeters with zero flow, the alert remains acknowledged. What do I do here? How do I keep that alert acknowledged while the value fluctuates slightly in the alarmed zone?

As always, thanks for the help!
-Tom


#2

Is this for PAC Display?
You want to look for a deadband or hysteresis setting.


#3

Yes, it’s PAC Display. I’m sorry, I should’ve identified the software.

Won’t hysteresis just keep the alarm in its current alarmed state? It’s not like the value is leaving the alarmed range, then returning and alarming again, it never leaves the range, just fluctuates within it and causes the acknowledged state to revert back to alarming.

As for deadband, it appears it’s not a setting for the alarm dynamic attribute. I do see it for other attributes, but not alarms.

I noticed that the value at the analog point goes out to ten-thousandths or more. Is there a way to reign this in to, say, hundredths at the PAC Manager level? As in, when I call for a dynamic attribute to see this value, I don’t need it to see that far out. This may also help with my alarming issue as the change causing the alert to reissue is usually is very, very minimal.

Thanks.