A backup device is required for an IC3-Modbus.
Is it possible to use two IC3-Modbus controllers to interrogate one Modbus slave device?
This configuration is acceptable where TCP is used, it cannot be used for RS485 RTU communications.
Each Modbus device on a TCP network must have a unique ID but everything else (such as register address, type, Gateway IP address) may be identical.
In a RS485 RTU modbus environment, there can only be one master device.