In-Situ Modbus connection client.

Use this to connect to In-Situ probes with Modbus protocol, such as:

* Aqua TROLL: 100, 200, 400, 600
* BaroTROLL: 500, Rugged
* Flow TROLL: 500
* Level TROLL: 300, 400, 500, 700
* RDO: PRO, PRO-X, TITAN
* Rugged TROLL 200