In-Situ Aqua TROLL 400 Modbus and SDI-12 Reference Guide - Manual (Page 9)

1.5 Modbus Master RS232 Wiring Diagram (Converter Required)
Cable length between Master and Slave must not exceed 1219.2 m (4000 ft). Rugged Cable
length between Master and Converter must not exceed 6 m (20 ft).
Signal Color
Ground/Return Black
External Power
(12-36 VDC, voltage limited by
converter)
Red
RS485 (-) Green
RS485 (+) Blue
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