Logix5k UDT's and Aliasing

I really wish RA would allow elements of User Defined Data Types to alias other Tags.

Does anyone know of a better work around than assigning them one by one? I normally use a Structured Text sub for the assignments but that actually defeats one of the main advantages of 5k by putting IO updates back into the scan and dependent (temporally anyway) on the size and complexity of the program.

Since I/O updates are independent of program scan it seem counterproductive to use program based assignments, but I don't know any other way of assigning vfd[9].enable to Local:O:12.Data.0 or vfd[3].speed to InfeedConveyor:O.FreqCommand

I love the ability to create UDT's to organize data, but I hate that I have to use program based assignments. Anyone know a better way?

I usually "feed" all my I/O through AOI handing functions.


Digital Inputs can be de-bounced in the AOI, alarms generated, forcing can be applied etc.


Analog Inputs and outputs can be scaled to/from Eng Units.


An added benefit is it synchronises the I/O to the PLC scan.


The picture shows an example of one I developed recently, but you can mix/match your own easily. The AOI's don't tie up your I/O points to aliased tags, so can be changed at runtime by editing the parameters. The output tag can be an element of a UDT.