Modbus RTU redundancy

Hi guys:
See attached files
A customer is asking about this solution for a small aqueduct.
Valves wil be butterfly 90° degrees turn, with modbus rtu redundant interface.
Does anybody have any experience with this item.
This is produced by emerson.

https://www.control-associates.com/...uator-accessories/controlinc-network-control/

Hi guys:
After we got the price for this interface box (Controlinc) the customer decided for a new approach . He wanted to make a ring out of modbus RTU (Redundant), I read lots of manuals and web pages to finally find out that this is not feasible.
The only way you can setup some kind of redundancy using modbus RTU is to use in my case valves with two modbus rtu interfaces and use two modbus rtu modules on the PLC one module for each modbus interface. Which means that we two independent modbus rtu networks not a ring.