ABB RELION REX640 Operation Manual page 125

1MRS759118 D
7.4.2.10 RS-485 bias and termination settings
A 6 x DIP switch is located on the COM1004...COM1005 cards. The COM card needs
to be pulled out from the relay case to access the switch. See
the location of the switch. RS-485 biasing and termination settings are possible
through this switch. If the switch is in "OFF" position, bias and termination are
disabled and in "ON" position, they are enabled.
Figure 103: DIP switches on the COM1004...COM1005 cards
Table 22: Bias and termination DIP switch
Switch
1
2
3
4
5
6
REX640
Operation Manual
Signal
RS485_A1/+
RS485_A1/+
RS485_B1/-
RS485_B1/-
RS485_A2/+
RS485_A2/+
RS485_B2/-
RS485_B2/-
Figure 103
X8 pin Type
8 Bias
Bus termination
7 Bias
10 Bias
Bus termination
9 Bias
Commissioning
for
OFF
ON
125