GE 994-0089 user manual RS-485 Connections, Cabling Requirements

GE Energy

4.4RS-485 Connections

The D400 accepts connections to RS-485 2-wire and 4-wire type devices through the RS-

485Adapter. The RS-485 Adapter (GE Part No. 520-0208) plugs into any serial communication slot (slots 1 through 8) on the D400. It contains two independently isolated RS-485 channels on a single terminal block: Channel 1 on terminals TB1-1 through TB1-5 and Channel 2 on terminals TB1-6 through TB1-10.

See section “3.4 RS-485 Adapter” for configuration options.

Cabling Requirements

The recommended total maximum length for RS-485 cables is 4000 ft [1300 m] when operating at 115 kbps. Refer to the manual of the connecting device for its recommended maximum cable length.

The cables must be shielded and the shield of each RS-485 cable section should be grounded at one end only. This prevents circulating currents and can reduce surge- induced current on long communication lines.

2-Wire Connections

»To connect RS-485 2-wire type devices to the RS-485 Adapter, use the following wiring connection:

Note: Before wiring devices, ensure that the RS-485 Adapter is configured to 2-wire mode (see section “3.4 RS-485 Adapter”).

Relay

RS485+

RS485-

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