In-Situ Aqua TROLL 400 Modbus and SDI-12 Reference Guide - Manual (Page 6)

1. Controller Requirements and Connections
The Multi-PRO 400 may be connected to a controller or logger for communication via:
• SDI-12
• RS485 Modbus
• RS232 Modbus (with converter)
1.1 Wiring Overview
Refer to the diagrams on the following pages. Trim and insulate unused wires. The shielded
wire should be wired to a chassis ground or earth ground.
Cable Stripped and Tinned
Signal Color
Ground/Return Black
External Power Red
No Connection Brown
RS485 (-) Green
RS485 (+) Blue
SDI-12 White
1.2 Power Connections
The Multi-PRO 400 requires an external 8 to 36 VDC power source. The red wire must be
connected to the positive terminal of the power source. The black wire must be connected to the
negative terminal of the power source, which is often referred to as the system ground or return.
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