For second solution (serial gateway to Modbus device) you will need
additionally a redirector software. Here the Lantronix redirector v3.xxx (see
appendix, chapter 6.3 ) could be a good option.
By the way, over the Barionet programming language BCL the Barionet can
communicate also as Modbus Master directly over Modbus with serially
connected Modbus/RTU slave devices, programming DEMOs for that are
available.
For the communication with Barionet extension units is no Barionet required,
they can also work standalone and communicate over RS485 with
Modbus/RTU to any other Modbus Master.
BARIX AG | 17. Oct. 2013 | Barionet Hands-on Training Guide | Page 22/38