Rs-485 Bias And Termination Settings - ABB RELION REX640 Technical Manual

1MRS759142 F
3.2.11

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
for 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 18: DIP switches on the COM1004...COM1005 cards
Table 40: Bias and termination DIP switch
Switch
1
2
3
4
5
6
REX640
Technical Manual
Signal
RS485_A1/+
RS485_A1/+
RS485_B1/-
RS485_B1/-
RS485_A2/+
RS485_A2/+
RS485_B2/-
RS485_B2/-
X8 pin Type
8 Bias
Bus termination
7 Bias
10 Bias
Bus termination
9 Bias
Basic functions
Figure 18
OFF
ON
93