ModbusTCP to Modbus Plus gateway to Modbus Plus PLCs

Do you or any of your customers have experience talking to a Niobrara R&D ModbusTCP to Modbus Plus gateway? Or any other ModbusTCP to Modbus Plus gateway? Modicon has several.

I can get the Modbus TCP v2 driver to connect to it, but have issues fishing data out.

The Modbus Plus side has multiple PLCs connected. That’s where the data is that I want to access.

The Niobrara has internal tables that contain the path list to a particular Modbus Plus node. Each entry in the table has an index. The unit has an IP address and then the index points to the particular MB+ node.

A Wonderware DAS ModbusTCP server is currently talking to the PLCs, so I know it works. Has been for years.



If I’m remembering the right emails/person we had no problems connecting and reading data.