Omron SYSMAC CS Series Operation Manual page 327

Fail-safe Circuits
Interlock Circuits
MCB1
MCB2
Note This configuration is possible with the C200HW-PA204R and C200HW-
PA204R Power Supply Units only. When a Power Supply Unit without a RUN
output is used, program the Always ON Flag (A1) as the execution condition
for an output point from an Output Unit. Do not include a circuit that stops the
controlled system by latching the RUN output during operation. Relay con-
tacts are used, and so chattering may cause incorrect operation.
When the PLC controls an operation such as the clockwise and counterclock-
wise operation of a motor, provide an external interlock such as the one
shown below to prevent both the forward and reverse outputs from turning ON
at the same time.
000501
CS-series
PLC
000502
This circuit prevents outputs MC1 and MC2 from both being ON at the same
time even if both CIO 000500 and CIO 000501 are both ON, so the motor is
protected even if the PLC is programmed improperly or malfunctions.
Power supply
CR1
Controlled system
Transformer
or noise filter
CS-series PLC
Twisted-pair wires
DC voltage
regulator
(See
PLC RUN
note.)
output
CR1 Surge suppressor
Interlock circuit
MC2
MC1
Section 5-1
+ DC
input/output
–
MC1 Motor clockwise
Motor counterclockwise
MC2
289