ABB RELION 611 Series Technical Manual page 514

Section 11
Protection relay's physical connections
508
Group Jumper connection
1-2
X7
2-3
1-2
X8
2-3
1-2
X9
2-3
1) Default setting
It is recommended to enable biasing only at one end of the bus.
Termination is enabled at each end of the bus.
It is recommended to ground the signal directly to earth from one node
and through capacitor from other nodes.
The optional communication modules include support for EIA-485 serial
communication (X5 connector). Depending on the configuration, the communication
modules can host either two 2-wire-ports or one 4-wire-port.
The two 2-wire ports are called COM1 and COM2. Alternatively, if there is only one
4-wire port configured, the port is called COM2.
Table 488: EIA-485 connections for COM0001-COM0003
Pin 2-wire mode
10 COM1
9
8 COM2
7
6 AGND (isolated ground)
5 IRIG-B +
4 IRIG-B -
3 -
2 GNDC (case via capacitor)
1 GND (case)
Description
B- bias enabled
1)
B- bias disabled
A+ bias enabled
1)
A+ bias disabled
Bus termination
enabled
Bus termination
1)
disabled
4-wire mode
A/+ COM2
B/-
A/+
B/-
1MRS757454 D
Notes
COM2
4-wire RX channel
Rx/+
Rx/-
Tx/+
Tx/-
611 series
Technical Manual