3rd Party IO Module
As the Ewon gateway includes a Modbus IO server, you can use any remote IO device that supports Modbus TCP or RTU to collect the local data.
To control the remote inputs and outputs of the Ewon gateway, you can create tags and associate them to the corresponding Modbus register using the Ewon embedded IO server labeled Modbus.
You can find more information about the Modbus IO server on the Ewon support website. Check for the document called Polling Data Registers from Modbus devices.
If you wish to read more about Ewon, its IO servers and their configuration, please refer to the RG-0007-00: Reference guide for IO Servers.