Can't create MG file in SLC/505

Ok I'm feeling really dumb right now. I was wanting to create an MG file in a SLC 5/05 processor. It is a 1747-L551C, OS501 Series C, FRN10. However in the dropdown list of available file types the only ones available are as you see in the attached image. What am I missing here?

I think that maybe you're confusing the features available with something like a MicroLogix 1400 (etc.) system with the features available with the SLC-5/05 platform ...

since they're both programmed with RSLogix 500 software, it's easy to forget which system you're working with ...

you can probably still do a Message command - but you'll have to use an "old-style" Integer (N-type) control block to make it happen ...

You are correct Ron. I don't work with SLCs that much anymore so I guess I had a brain freeze. Thanks for giving me a gentle reminder.

The PLC-5 controllers originally used blocks of Integer (N) data file memory for the Control blocks of MSG instructions, and later added the structured specific-purpose MG type data file.

But the SLC-5/05 never added that structured data file type. You still use blocks of Integer (N) data files. For Ethernet messages, makes sure you reserve 51 words for each Message instruction.