I have some big UDTs. I want to evaluate the complete UDT (all UDT members) in expression language, and return the current highest active alarm severity. How? Does a master UDT have properties for this?
Unfortunately the master UDT doesn’t have alarm properties, you need to create your own tag in the UDT. Create an expression tag in the master UDT that looks for the max value of each of your alarms’ .AlarmHighestUnackPriority and .AlarmHighestAckPriority properties. When creating the expression you can’t use the GUI to select the tag properties just the tags, so you’ll need to type the properties in. Also, if you have edited any of the instance UDTs where you have disabled one of the alarm tags you’ll want to edit the expression and remove that tag from the instance’s expression, else you’ll get an unknown quality overlay.
max({[.]../Alarm/High.AlarmHighestUnackPriority},
{[.]../Alarm/Low.AlarmHighestUnackPriority},
{[.]../Alarm/High.AlarmHighestAckPriority},
{[.]../Alarm/Low.AlarmHighestAckPriority})