This article describes how many Modbus devices that can be connected to the serial Interface of the Ewon Netbiter.
Ewon Netbiter EC310 / Ewon Netbiter EC350 / Ewon Netbiter EC360
How many Modbus devices can be connected to the serial interface of the Netbiter?
RS-485 = 32, RS-232 = 1
Note: The two serial interfaces cannot be used at same time for Modbus.