There is no serial port on the groov Box and groov Server for Windows does not support serial ports.
So, yeah, its ModbusTCP only.
We have done some experiments with ModbusRTU to ModbusTCP converters, and once you get them setup right, they work rather well.
The ‘big deal’ with this converter is that it has a buffer, so if the serial is slow, or there are many serial units on the drop, then the unit will not time out on the TCP side due to the buffer.
If you only have one serial device and its faster than 9600 baud, you probably do not need the buffer.
We are using a bit of the fieldserver gear around the place with groov (they have many different protocol converters).
Yes, it can connect to multi drop serial devices, in other words, more than one.
(You may have to jigger with the config file and put the serial address in for each device).
The whole point of this unit is that if you have a LOT of say 300 baud serial devices, you may not be able to poll them all at the 1 second rate that groov polls at, so with buffer, groov does not time out and you get the data as quick as you can.