Vijeo and Modbus ascii

I'm trying to use a Schneider HMI to communicate to a PC machine that uses serial modbus ascii. The driver for the PC was created in assembler and written in house.

If I load a new driver in the IO manager for Vijeo there is only:
Modbus RTU
Modbus Plus
Modbus TCP/IP
and a few others.

Has anyone used a 3rd party driver or how should I handle this?

My options are:
1)Have our engineer write a new driver for Modbus RTU (which he said he will do no problem)
2)Use another HMI
3)I see there are some sort of gateway adapters, maybe one of these could go from ascii to RTU?

If I go with a Schiender PLC to handle it the help file in CodeSys shows all sorts of commands for modbus, but man I'm confused as hell using the read\write commands and function blocks. Even the examples have me just staring at the screen for hours..

Send halp!

Hi,

You could use something like a Redlion DSPLE000 Gateway. It should be able to do a protocol conversion between Modbus RTU and Modbus ASCII.

Redlion also do an HMI which has the same protocol capabilities.

Modbus ASCII is really rare. I have not come across it in all my years in the automation business.