DataMonitoredItem DeadBand "Percent"

[nwhelchel]

Does anyone know how this is supposed to work? "None" and "Absolute" work fine, but "Percent" doesn't seem to.

My assumption is that if I put a 2% deadband for an item the data will be considered changed based on a 2% change (+ or -) from the previously updated/sent value. However, setting the deadband to "2.0" and the dead band type to "Percent" yields no data ever being sent at all, not even the first data value!

The percent is very useful for us because we have some vacuum gauges being monitored that vary between atmosphere and 2e-6 torr, for instance, so at atmosphere the 2% would be a larger delta to be filtered than in the 2e-6 range and the unwanted noise when sitting at these extremes can be eliminated.

Has anyone else experienced this issue or is there something that I am not getting.

Regards,
Nathan

[Support Team]

Hello Nathan,

The DeadbandType.Percent is only valid for variables that have a EURange property.

Specification:
"For this type of deadband the deadbandValue is defined as the percentage of the EURange. That is, it applies only to AnalogItems with an EURange Property that defines the typical value range for the item. This range shall be multiplied with the deadbandValue and then compared to the actual value change to determine the need for a data change notification."

We will upate the documentation for DeadbandType.

So for your use case there is no proper DeadbandType defined.

Best regards
Support Team