2-Wire And 4-Wire Connections - Omron SYSMAC CS1W-SCB41-V1 Operation Manual

Wiring
3-3-7

2-Wire and 4-Wire Connections

Example of 4-Wire
Connections
2/4-wire switch
(DPDT)
Board
Note
98
Communications
cables
PLC power supply
and general control
circuit wiring
Power lines
• If the I/O wiring and power cables must be placed in the same duct, they
must be shielded from each other using grounded steel sheet metal.
Communications
cables
The transmission circuits for 2-wire and 4-wire connections are different, as
shown in the following diagram.
Other Unit
Other Unit
1. Use the same transmission circuit (2-wire or 4-wire) for all nodes.
2. Do not use 4-wire connections when the 2/4-wire switch on the Board is
set to 2-wire.
3. In protocol macro mode, do not use full-duplex transmissions when the 2/
4-wire switch on the Unit is set to 2-wire. Otherwise, the data sent from the
Serial Communications Board or Unit will be directly returned as receive
data. In this case, the Board or Unit cannot determine whether the data in
the reception buffer is its own send data or the data received from a remote
node, and thus cannot perform receive processing properly. To avoid this
problem, always use half-duplex transmissions with a 2-wire setting. Either
half-duplex or full-duplex transmissions can be used with a 4-wire setting.
Low-current cables
Control cables
Power cables
Ground to 100 Ω or less.
PLC power supply
and general control
circuit wiring
Power lines
Ground to 100 Ω or less.
Example of 2-Wire
Connections
2/4-wire switch
(DPDT)
Other Unit
Not connected
Board
Section 3-3
300 mm min.
300 mm min.
Steel sheet metal
200 mm min.
Other Unit