Rs-485 Multi Unit / In Line Example; Rs-485 Half Duplex Wiring Example - Campbell SDM-SIO1A Instruction Manual

SDM-SIO1A Serial Input/Output Module

3.3.2 RS-485 multi unit / in line example

+12V
G
C1
C2
C3
RG
G
RTS/TD+
TX/TD-
RX/RD+
CTS/RD-
NOTE

3.3.3 RS-485 half duplex wiring example

+12V
G
C1
C2
C3
RG
G
RTS/TD+
TX/TD-
RX/RD+
CTS/RD-
10
To logger
As with all RS-485 configurations the use of termination resistors is
optional. They tend not to be required with shorter cable runs and
with modern slew-rate limited driver technology (as used in the
SDM-SIO1A).
To logger
RS485 0V can be connected
straight to 0V but, this is not
recommended for long wire
lengths.
* Note connection order
First RS485
RS485 0V
equipment
RS485 TD+
with
RS485 TD-
termination
RS485 RD+
resistors
* No RD-onnection order
RS485 RD-
RS485 0V Second RS485
equipment
RS485 TD+
with
RS485 TD-
termination
RS485 RD+
resistors
RS485 RD-
RS485 0V can be connected
straight to G but, this is not
recommended for long wire
lengths.
* Note connection order
First RS485
RS485 0V
equipment
RS485 TD+
with
RS485 TD-
termination
RS485 RD+
resistors
RS485 RD-