Alert Deadband

I can’t seem to get the Alert Deadband working and there doesn’t seem to be anything on it in the manual.

I’ve set up a new DB tag (type Int4) with an Analog alarm with Low Setpoint 50 (exclusive), High Setpoint Infinite and an Alert Deadband of 10. My understanding of this is that it should trigger over 50 and needs to drop to 40 before it goes back out of alarm. It does trigger over 50, but it goes back out of alarm at 50.

Am I overlooking something obvious?


Indeed there was a small problem with the alert deadband. I believe with the way it was set up, a clear message wouldn’t be sent, but the tag properties would say that it was clear when it shouldn’t be.

As it is, the way it works is that the tag goes into alarm immediately. It only clears when the value is +/- the deadband away from high/low setpoint. If it’s an “any change” state, the alert only occurs when the tag changes by the deadband from the last value that caused an alert.

This has been fixed for 7.0.5.


I’ve just tried the alert deadband feature again in version 7.0.9 and it still doesn’t work - the alert log shows that a clear message is being sent immediately the value drops below the alarm level, ignoring the alert deadband. This happens whether the Alerting Setup / Notification Settings / Send Clear setting is true or false.

And this is with the same setup as described in the first post? I can’t replicate it… maybe export the tag as a CSV?


CSV attached (with extra extension as forum doesn’t like CSVfiles).
sqltags.csv.txt (893 Bytes)

Thanks. I don’t know what I was doing wrong yesterday, but I reproduced it right away when I loaded your tag.

It’ll be fixed in the next release. The problem is caused by the “infinite” high end. If you just switch the high setpoint to a big number you shouldn’t have a problem, but like I said, it’s been fixed for the next update.


Thanks Colby.