Omron CJ Series Operation Manual page 24

Safety Precautions
Fail-safe Measures
Unintended outputs may occur when an error occurs in variable
memory or in memory used for CJ-series Units. As a
countermeasure for such problems, external safety measures must
be provided to ensure safe operation of the system.
Provide measures in the communications system and user program
to ensure safety in the overall system even if errors or malfunctions
occur in data link communications or remote I/O communications.
If there is interference in remote I/O communications or if a major
fault level error occurs, output status will depend on the products
that are used.
Confirm the operation that will occur when there is interference in
communications or a major fault level error, and implement safety
measures.
Correctly set all of the EtherCAT slaves.
The NJ-series Controller continues normal operation for a certain
period of time when a momentary power interruption occurs. This
means that the NJ-series Controller may receive incorrect signals
from external devices that are also affected by the power
interruption. Accordingly, take suitable actions, such as external fail-
safe measures and interlock conditions, to monitor the power supply
voltage of the external device as required.
You must take fail-safe measures to ensure safety in the event of
incorrect, missing, or abnormal signals caused by broken signal
lines, momentary power interruptions, or other causes. Not doing so
may result in serious accidents due to incorrect operation.
Voltage and Current Inputs
Make sure that the voltages and currents that are input to the Units
and slaves are within the specified ranges.
Inputting voltages or currents that are outside of the specified ranges
may cause accidents or fire.
Downloading
Always confirm safety at the destination before you transfer a user
program, configuration data, setup data, device variables, or values
in memory used for CJ-series Units from the Sysmac Studio. The
devices or machines may perform unexpected operation regardless
of the operating mode of the CPU Unit.
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WARNING
CJ-series CompoNet Master Unit Operation Manual for NJ-series CPU Unit (Cat. No. W493)