Rs-485 Bias And Termination Settings; Serial Link Diagnostics And Monitoring - ABB RELION REX640 Technical Manual

1MRS759142 C
3.2.9
3.2.10
REX640
Technical Manual
LED
X8 TX
X8 TX
IRIG-B

RS-485 bias and termination settings

A 6 x DIP switch is located on the bottom side of the COM1004...COM1005 boards.
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.
Table 24: Bias and termination DIP switch
Switch Signal
1 RS485_A1/+
2 RS485_A1/+
RS485_B1/-
3 RS485_B1/-
4 RS485_A2/+
5 RS485_A2/+
RS485_B2/-
6 RS485_B2/-

Serial link diagnostics and monitoring

Serial communication diagnostics and monitoring is divided between the serial link
driver and the serial communication protocol. The lower-level physical and protocol-
independent aspects of the UART-based serial communication are monitored in the
serial link driver. Diagnostic counters and monitoring values are located on the HMI
under Monitoring/Communication/COMn (n= 1,2,...).
Depending on the communication protocol, the serial driver software receives single
characters or complete protocol frames, based on the frame start/stop characters or on
link frame timing.
Table 25: Setting parameters
Parameter
Fiber mode
Serial mode
Baudrate
Basic functions
Description
RS-485/COM2
RS-485/COM1
IRIG-B
X8 pin Type
8 Bias
Bus termination
7 Bias
10 Bias
Bus termination
9 Bias
Description
Defines the fiber-optic mode used. Setting "No
fiber" is the same as galvanic mode.
Used for galvanic RS-485 modes 2- or 4-wire. This
Fiber mode is set to "No
setting is relevant only if
fiber".
Communication speed used
Section 3
93