Application Precautions - Omron CJ1W-NC271 - 12-2009 Operation Manual

Application Precautions

!Caution The operating environment of the PLC System can have a large effect on the
5 Application Precautions
!WARNING
!Caution Failure to abide by the following precautions could lead to faulty operation of
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longevity and reliability of the system. Improper operating environments can
lead to malfunction, failure, and other unforeseeable problems with the PLC
System. Make sure that the operating environment is within the specified con-
ditions at installation and remains within the specified conditions during the
life of the system.
Observe the following precautions when using the PLC System.
Always heed these precautions. Failure to abide by the following precautions
could lead to serious or possibly fatal injury.
• Always connect to a ground of 100 Ω or less when installing the Units. Not
connecting to a ground of 100 Ω or less may result in electric shock.
• Always turn OFF the power supply to the PLC before attempting any of
the following. Not turning OFF the power supply may result in malfunction
or electric shock.
• Mounting or dismounting Power Supply Units, I/O Units, CPU Units, In-
ner Boards, or any other Units.
• Assembling the Units.
• Setting DIP switches or rotary switches.
• Connecting cables or wiring the system.
• Connecting or disconnecting the connectors.
the PLC, the PCU, or the system, or could damage the PLC or PCU. Always
heed these precautions.
• Fail-safe measures must be taken by the customer 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
cause malfunction resulting in serious injury.
• Interlock circuits, limit circuits, and similar safety measures in external cir-
cuits (i.e., not in the Programmable Controller) must be provided by the
customer.
• Install external breakers and take other safety measures against short-cir-
cuiting in external wiring. Insufficient safety measures against short-cir-
cuiting may result in burning.
• For CS-series PLCs, always tighten the mounting screw at the bottom of
the PCU to a torque of 0.4 N⋅m.
• For CJ-series PLCs, lock the sliders securely until they click into place
when connecting the Power Supply Unit, CPU Unit, I/O Units, Special I/O
Units, or CPU Bus Units. Functions may not work correctly if the sliders
are not locked properly.
• Always attach the End Cover provided with the CPU Unit to the Unit on
the right end of the PLC. The CJ-series PLC will not operate properly if
the End Cover is not attached.
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