ABB Relion 620 Series - Page 1186

Group Jumper connection Description
X21
1-2
2-3
EIA-485
EIA-232
X26
1-2
2-3
EIA-485
EIA-232
To ensure fail-safe operation, the bus is to be biased at one end using the pull-up
and pull-down resistors on the communication module. In the 4-wire connection,
the pull-up and pull-down resistors are selected by setting jumpers X5, X6, X8 and
X9 to enabled position. The bus termination is selected by setting jumpers X7 and
X11 to enabled position.
The jumpers have been set to no termination and no biasing as default.
Table 1074: 2-wire EIA-485 jumper connectors for COM1
Group Jumper connection Description Notes
X5
1-2
2-3
A+ bias enabled
A+ bias disabled
1
COM1
Rear connector X6
2-wire connection
X6
1-2
2-3
B- bias enabled
B- bias disabled
1
X7
1-2
2-3
Bus termination ena-
bled
Bus termination disa-
bled
1
Table 1075: 4–wire EIA-485 jumper connectors for COM1
Group Jumper connection Description Notes
X5
1-2
2-3
A+ bias enabled
A+ bias disabled
1
COM1
Rear connector X6
4-wire TX channel
X6
1-2
2-3
B- bias enabled
B- bias disabled
1
X7
1-2
2-3
Bus termination ena-
bled
Bus termination disa-
bled
1
X9
1-2
2-3
A+ bias enabled
A+ bias disabled
1
4-wire RX channel
Table continues on the next page
1
Default setting
IED physical connections 1MRS757644 H
1186 620 series
Technical Manual