Siemens 9810 Series, User Manual, Page: 40 / 218

Communications
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 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, the meter
webpages or 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 master over RS-485
communications, and set the RS-485 bias to OFF when the meter is acting as a
slave. You can configure RS-485 biasing through ION Setup, the meter webpages
or display.
Serial protocols and ports
Your meter supports serial communications protocols on its RS-485 ports.
• ION
• Modbus RTU
• Modbus Master
• DNP 3.0
• EtherGate
• GPS: Truetime/Datum 1
• GPS: Arbiter 1
• GPS: Arbiter-Vorne 1
• None 2
1 These protocol settings are used for connecting to a GPS receiver communicating in serial ASCII
format.
2 This protocol setting stops communications using this port.
Configuring serial communications settings using ION Setup
Use ION Setup to configure the meter’s serial communications settings.
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