It is useful, to activate both the pull-up and the pull-down resistors, which only are necessary
once on every bus line, at the bus master.
Serial
Interface
Pin Signal Interface Description
1 FE - Functional earth
2 TxD RS-232 Transmit data Output
3 RxD/TxD-P RS-485 Receive/Transmit Positive
4 RTS RS-232 Request to send Output
5 SGND Signal ground 0 V supply out
6 +5 V - 5 V supply out
7 RxD RS-232 Receive data Input
8 RxD/TxD-N RS-485 Receive/Transmit Negative
9 CTS RS-232 Clear to send Input
Shield FE - Functional earth
NOTICE!
Risk of corrosion!
Unused connectors and slots may corrode if XC devices are used in salt-mist
environments.
Protect unused connectors and slots with TA535 protective caps for XC devices
TA535
Ä
Chapter 1.8.4.6 “TA535 - Protective Caps for XC Devices”
on page 1172.
The following drawing shows an RS-485 bus with the bus master at the line end.
1 Master at the bus line end, pull-up and pull-down activated, bus termination with 120 Ω
resistors
2 Slave within the bus line
3 Slave at the bus line end, bus termination with 120 Ω resistors
If the master is located within the bus line, it does not need a terminating resistor. The pull-up
and the pull-down resistors, however, are necessary:
Pin assignment
System Assembly, Construction and Connection
AC500 (Standard) > Connection and Wiring
2019/04/17 3ADR010121, 13, en_US 1281
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