Question:
Can several PLCs with communication RS485 be connected to a Serial/Ethernet converter when they are using a Modbus driver?
Solution:
Yes, this is possible. In this case, the Modbus driver will send the serial information encapsulated as Ethernet to the converter, which will in turn remove this encapsulation and send the serial information to the PLCs. The driver will connect to the Ethernet network via an IP and a port, and each tag’s N1 parameter will set which address from the 485 network’s slave must read and write.
On driver settings, set all options from Ethernet tab, and keep RTU mode configured on Modbus tab.
NOTE: Neither RTU mode nor ASC mode are suitable for TCP/IP communication, and it is possible that the driver return invalid values because some responses may have been received late. Because of RTU’s and ASC’s modes features, there is no way to avoid this risk. The risk can, however, be decreased if the communication timeout’s value is increased.
