Omron CVM1 Series, Operation Manual

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Safety Precautions 3
3 Safety Precautions
!WARNING
Do not touch any of the terminals or terminal blocks while the power is being
supplied. Doing so may result in electric shock.
!WARNING
Do not attempt to disassemble, repair, or modify any Units. Any attempt to do
so may result in malfunction, fire, or electric shock.
!WARNING
Provide safety measures in external circuits (i.e., not in the Programmable
Controller), including the following items, to ensure safety in the system if an
abnormality occurs due to malfunction of the PLC or another external factor
affecting the PLC operation. Not doing so may result in serious accidents.
• Emergency stop circuits, interlock circuits, limit circuits, and similar safety
measures must be provided in external control circuits.
• The PLC will turn OFF all outputs when its self-diagnosis function detects
any error or when a severe failure alarm (FALS) instruction is executed.
As a countermeasure for such errors, external safety measures must be
provided to ensure safety in the system.
• The PLC outputs may remain ON or OFF due to deposits on or burning of
the output relays, or destruction of the output transistors. As a counter-
measure for such problems, external safety measures must be provided
to ensure safety in the system.
• When the 24-V DC output (service power supply to the PLC) is over-
loaded or short-circuited, the voltage may drop and result in the outputs
being turned OFF. As a countermeasure for such problems, external
safety measures must be provided to ensure safety in the system.
!Caution Execute online editing only after confirming that no adverse effects will be
caused by extending the cycle time. Otherwise, the input signals may not be
readable.
!Caution Confirm safety at the destination node before changing or transferring to
another node the contents of a program, the PLC Setup, I/O tables, or I/O
memory. Changing or transferring any of these without confirming safety may
result in injury.