After spending a little more time on this, I think the issue is how Allen Bradley handles "STRING DATA".(Now I'm working with a Micro850 as I don't have a Compact or control logix PLC)
When you setup a Tag as a string AB actually breaks it down into an "ARRAY" and then uses the ASCII(Decimal value) as the "VALUE".
Thats how come the Maple System can't see that data. The maple system stores ASCII into "WORD".
So with that in mind I have wrote a "MACRO" that will transfer the AB Tag value-array in the local LW memory of the maple system and now the maple will treat this data as "STRING".
This way you can send your value OUT with MQTT.
The only thing I need to know is what will be the MAXIMUM CHARACTERS in your string value. I can plug this into the macro and then you can edit the macro for your needs and I think it will work for you.
Just let me know.