Omron CJ Series Operation Manual page 23

During Power Supply
Do not touch any of the terminals or terminal blocks while the power
is being supplied. Doing so may result in electric shock.
Do not attempt to take any Unit apart. In particular, high-voltage
parts are present in the Power Supply Unit while power is supplied
or immediately after power is turned OFF. Touching any of these
parts may result in electric shock. There are sharp parts inside the
Unit that may cause injury.
Fail-safe Measures
Provide safety measures in external circuits to ensure safety in the
system if an abnormality occurs due to malfunction of the CPU Unit,
other Units, or slaves or due to other external factors affecting
operation. Not doing so may result in serious accidents due to
incorrect operation.
Emergency stop circuits, interlock circuits, limit circuits, and similar
safety measures must be provided in external control circuits.
The Controller outputs may remain ON or OFF due to deposition or
burning of the output relays or destruction of the output transistors.
As a countermeasure for such problems, external safety measures
must be provided to ensure safe operation of the system.
The CPU Unit will turn OFF all outputs from Basic Output Units in
the following cases. The remote I/O slaves will operate according to
the settings in the slaves.
• If an error occurs in the power supply
• If the power supply connection becomes faulty
• If a CPU watchdog timer error or CPU reset occurs
• If a major fault level Controller error occurs
• While the CPU Unit is on standby until RUN mode is entered after
the power is turned ON
External safety measures must be provided to ensure safe operation
of the system in such cases.
If external power supplies for slaves or other devices are overloaded
or short-circuited, the voltage will drop, outputs will turn OFF, and the
system may be unable to read inputs. Provide external safety
measures in controls with monitoring of external power supply
voltage as required so that the system operates safely in such a
case.
CJ-series CompoNet Master Unit Operation Manual for NJ-series CPU Unit (Cat. No. W493)
WARNING
Safety Precautions
21