String udt expression tag

Hello, in my ignition 7.6.1-rc4 (b2257), whenever i create string expression tag in my udt structure and bind it some string udp parameter, its value doesn’t show up unless it is a number. Any thoughts?

I’ve run into something similar - has anyone else?

If you are just trying to mimic what is in the value of the parameter in your UDT, use a string type memory tag instead, and set the value to the parameter name enclosed in braces.

So if you have, let’s say, an integer type parameter named DeviceNumber, you would create a string type memory tag and name it something like DeviceNumberString. Then set the value of it to {DeviceNumber}. When you look at that DeviceNumberString tag in your UDT, it should show you the string representation of the integer value of your DeviceNumber parameter.

Definitely interesting… and thank you. However, here’s the direction I was going:

Set up a UDT with two parameters:

DeviceID (String)
TagID (String)

So… in the path for an OPC member of the UDT: [PLC]Program:{DeviceID}.{TagID}.Open

The parameters as string type do not work… However…

DeviceID (Integer)
TagID (Integer)


Works fine.

Now in my template parameters - the former example does work.

I will be the first to admit that I have not dug through all of the documentation yet.

I almost always use string types for my UDT parameters and haven’t noticed this in the new 7.5/7.6 versions. Are you still seeing this issue? Your OPC Item path (Unitx.Openy) will be case sensitive, maybe that is the problem?