RS-485 wiring

Connect the devices on the RS-485 bus in a point-to-point configuration, with the (+) and (-) terminals from one device connected to the corresponding (+) and (-) terminals on the next device.

RS-485 cable

Use a shielded 2 twisted pair or 1.5 twisted pair RS-485 cable to wire the devices. Use one twisted pair to connect the (+) and (-) terminals, and use the other insulated wire to connect the C terminals

The total distance for devices connected on an RS-485 bus should not exceed 1200 m (4000 ft).

RS-485 terminals

C Common. This provides the voltage reference (zero volts) for the data plus and data minus signals
Shield. Connect the bare wire to this terminal to help suppress signal noise that may be present. Ground the shield wiring at one end only (either at the master or the last slave device, but not both.
- Data minus. This transmits/receives the inverting data signals.
+ Data plus. This transmits/receives the non-inverting data signals.
NOTE: If some devices in your RS-485 network do not have the Common terminal, use the bare wire in the RS-485 cable to connect the Common terminal from the meter to the shield terminal on the devices that do not have the Common terminal.
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