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 client or the last server
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 C terminal, use the bare wire in
the RS-485 cable to connect the C terminal from the meter to the shield terminal on the devices
that do not have the C terminal.
RS-485 configuration
Before connecting your device to the RS-485 bus, use ION Setup, meter webpages or the display
to configure your meter’s default RS-485 settings.
Your meter has two RS-485 connections.
Each RS-485 connection must have a unique unit identifier (Unit ID) and have the following
settings match the rest of the devices on the RS-485 bus:
•
Protocol
•
Baud rate
•
Parity and stop bits
You can configure the following settings to help optimize communications performance:
•
RTS delay
•
RS-485 bias
You can use a communications converter (USB to RS-485 or RS-232 to RS-485) or an Ethernet
gateway device to connect to your meter.
RS-485 bias
You can use the RS-485 bias setting to fine-tune communications.
Set the RS-485 bias to ON when the meter is acting as a client over RS-485 communications and
set the RS-485 bias to OFF when the meter is acting as a server. You can configure RS-485
biasing through ION Setup, the meter webpages or the display.
9810 series - User manual Communications
7EN05-0390-08 88
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