UDT Alarm Deadband

Can someone else please verify that they are seeing the same issue with the Alarm deadband inside a UDT. What I am seeing is that when I try to set the alarm deadband to a UDT tag it causes all of the tags in the UDT to go to a unknown state. I have attached the UDT there is only one value that has an alarm at this point that is the Value_in tag. this UDT does not have the deadband for this tags alarm set in it.
We are running 7.6.2.rc1

Any thoughts?
RTDUDT.xml (19.5 KB)


I’m not seeing this. Is it still happening? Since that UDT uses many OPC items that I don’t have, the best I can do is mock up a similar structure, and I’m not running into a problem.

If the values are going to “unknown”, my best guess is that perhaps an error is occurring on initializing the instance, and it’s ending up in some half-started state. Is there anything in the gateway console? If you disable and re-enable the instance, the error should happen again.


I have attached a test UDT that you can use it does the same thing pointing to the simulator so you should be able to see what I am talking about. If you simple remove the binding from the alarm deadband all is well. running 7.6.2 rc5
testUDT.xml (1.16 KB)

Thanks, I’ve tracked it down. When the tag is initialized, the first referenced opc value hasn’t come in yet, and so the value is null, causing a problem on the alarm init. It has been fixed for 7.6.3. If you need a workaround, bind it to an expression instead:



Great Thanks Colby