Compare UDT's?

Is it possible to compare two tags using the same UDT? I've tried the compare statement but I get errors. Both tags are using the same UDT's as their data types. So both tags have the same formate.

what PLC?

I would expect that you could compare parts of the UDT, if for instance one part is a DINT, you should be able to compare the DINT's individually.

I doubt any PLC would have a compare function where you could compare the whole UDT structure.

Logix5000 does not have any inherent method I know of for comparing UDT's, aside from element by elelment.

You can hack it I suppose, with the FBC instruction, but my gut feeling is that it would not work properly, (padding) and even if it did, it's only going to say that some bit at some offset is different.

Why do you need to compare UDT's for equality? You must be looking for (in)equality, as if you are trying to do greater then or less then, you already have a certain ordering scheme in mind.

I want to compare a UDT to see if an operator has changed any of the information available on the HMI. If the information has changed then I have other things that need to be done. In my case, there aren't to many elements in the UDT so its not a big deal to compare them individually. I just thought it would be better to do a compare with one instruction. I am using logix50000.