Logix Add-on Instruction advice

Having only just gotten into add-on instructions, with no current projects using it, I'm in the early experimentation phase, so I thought I'd come around here to solicit some good advice.

So, in the example I'm working out, I have a physical device that I'd like to wrap in it's on instruction. The device (a big circuit breaker) will always have it's own modbus address, and will be fairly consistent in function, but often differing in modbus addresses based on brands, and so on. So, with this brief overview, here are some questions I have come up with, which I couldn't find answers to:

1. These breakers already have their own user-defined type, but the Add-on seems to only allow for the primitive data types (INT, etc..) to be used, so I can't simply pass in my "breaker" udt, rather I have to wire up each of it's inputs directly. That makes the instruction quite "tall", and rather unwieldy, so I feel i'm on the wrong track.

2. As mentioned before, we have similar equipment, but often not the same equipment. Is it possible to do "inheritence", to use a C word? I recall hearing bits and pieces about this at Automation Fair in Nashville, but haven't seen much about it since then. Was i dreaming? Could I make a "basic" object, and then a bunch of child objects which I can tweak to meet the specific needs?

- thanks!!

(v16)

I believe if you speicfy the datatype as in/out, you can pass complex data types.

Here i have a user-defined datatype called "Breaker", and when I try to save it, it pops that dialog

Click on Usage - drop down to InOut type.
I'm 99% sure it will allow this.

Oh, excellent. I read your post as "IN or OUT", not "InOut", which I never tried.

This is perfect. That was going to be a big issue!

Good, now we got that cleared.

Now on to #2:
UDTs can be a sub element of a larger UDT.
I can have a UDT called drive with:

On (datatype bool)
Off (datatype bool)
FWD (datatype bool)
REV (datatype bool)

& we create a UDT called DriveAxis with:

Position (datatype real)
Velocity (datatype real)
VFD (datatype drive)

Now we declare an element named MyDriveAxis
Now whe have:

MyDriveAxis.Position (datatype real)
MyDriveAxis. Velocity (datatype real)
MyDriveAxis.VFD.On (datatype bool)
MyDriveAxis.VFD.Off (datatype bool)
MyDriveAxis.VFD.FWD (datatype bool)
MyDriveAxis.VFD.REV (datatype bool)

Yeah, nested instructions. I've been headed that way all afternoon, since it worked so well in user-defined types.

I may make, for example, a nice big functional instruction, but inside have various "network layer" instructions that hook up a particular point to a particular modbus address.

It's not actual inheritance, but I definitely think it will accomplish the need.

I appreciate the insight!