Omron CJ2 CPU UNIT - Electrical Diagram; Emergency Stop Circuit; Interlock Circuits

5-3
5 Installation
CJ2 CPU Unit Hardware User’s Manual
5-1 Fail-safe Circuits
5
The following emergency stop circuit controls the power supply to the controlled system so that power is
supplied to the controlled system only when the PLC is operating and the RUN output is ON.
An external relay (CR1) is connected to the RUN output from the Power Supply Unit
*1
as shown in the
following diagram.
*1 A RUN output is provided only on the CJ1W-PA205R Power Supply Unit. 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.
z Electrical Diagram
When the PLC controls an operation such as the clockwise and counterclockwise operation of a motor,
provide an external interlock such as the one shown in the following example to prevent both the for-
ward and reverse outputs from turning ON at the same time.
This circuit prevents outputs MC1 and MC2 from both being ON at the same time even if both
CIO 000501 and CIO 000502 are ON, so the motor is protected even if the PLC is programmed improp-
erly or malfunctions.
Emergency Stop Circuit
Interlock Circuits
MCB1
MCB2
CR1
CR1
DC
PLC RUN
output
input/output
Power supply
Controlled system
DC voltage
regulator
Surge suppressor
Twisted-pair wires
Transformer
or noise filter
CJ-series
PLC
CJ-series
PLC
MC2
000501
MC1
000502
MC1
MC2
Interlock circuit
Motor clockwise
Motor counterclockwise