Intelligent Modbus Gateway Required


I have a situation at my plant, where I need to interface my existing PLC with some field devices Via Modbus Interface. I can not change the program of existing PLC, but I have Modbus slave addresses and register details that are required to communicate with field devices. I want to connect PLC with a gateway that can read the Modbus requests from PLC for each slave (via a single Modbus RTU Communication Port) and poll it intelligently to new addresses via ethernet interface. Attached is a snapshot. Can someone refer how can I achieve this gateway functionality?


No problem, very easy to make with a Pro-face GP4201TAD touchpanel.
It has a modbus RTU port that you connect to the PLC that will act as the various modbus RTU slave(s).
And it has an ethernet port that you configure as a modbus TCP master that reads all field devices over the ethernet.
Inside the touchpanel you can use ladder logic or a script to copy the info read from the TCP slave(s) to the RTU slave(s).
Very easy to program and you can show the data on the screen of the touchpanel.
You can even let the touchpanel simulate the modbus TCP values for initial testing.
See our GP4000 series
Our ETH-1000 gateway could be used for this application. Although its Modbus RTU Slave driver supports only 1 Modbus address, the Generic Serial Slave driver can be used instead, in conjunction with the ETH-1000's Database Logic feature, to dynamically respond with the correct Modbus/TCP device data based on the requested Modbus RTU slave address.

I've created and attached a complete configuration project for the ETH-1000 for this application (however, you may need to change the baud rate and parity settings). The project can be viewed using our ICC Configuration Studio available as a free download here:

Details and pricing on the ETH-1000 can be found on its product page here:

I am the product specialist for the ETH-1000 at ICC, so feel free to email me directly or submit a support ticket on our website if you have any questions on the ETH-1000.