Omron NX701-1620, User Manual

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13
Safety Precautions
NX-series CPU Unit Hardware User’s Manual (W535)
Warnings
WARNING
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, slaves, or Units 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 countermea-
sure 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 Digital Output Units in the follow-
ing cases. The slaves will operate according to the settings in the slaves.
• If an error occurs in the power supply
• If a CPU 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
• If a system initialization error occurs
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 sys-
tem operates safely in such a case.