Safety Precautions - Mitsubishi Electric MELSEC Q Series User Manual

Before using this product, please read this manual and the relevant manuals carefully and pay full attention
to safety to handle the product correctly.
In this manual, the safety precautions are classified into two levels: "
WARNING
CAUTION
Under some circumstances, failure to observe the precautions given under "
serious consequences.
Make sure that the end users read this manual and then keep the manual in a safe place for future
reference.
[Design Precautions]
● Configure safety circuits external to the C Controller module to ensure that the entire system
operates safely even when a fault occurs in the external power supply or the C Controller module.
Failure to do so may result in an accident due to an incorrect output or malfunction.
(1) Configure external safety circuits, such as an emergency stop circuit, protection circuit, and
protective interlock circuit for forward/reverse operation or upper/lower limit positioning.
(2) If the following status (a) or (b) occurs, the system will behave accordingly.
(a)When overcurrent or overvoltage protection of the power supply module is activated, the
outputs (Y) from the user program and writing to the buffer memory are disabled, and all
outputs are turned off.
(b)When the C Controller module detects an error such as a watchdog timer error by the
selfdiagnostic function, the outputs (Y) from the user program and writing to the buffer
memory are disabled. Whether to hold or turn off all outputs can be set by parameters.
All outputs may turn on when an error occurs in the part, such as I/O control part, where the C
Controller module cannot detect any error.To ensure safety operation in such a case, provide a
safety mechanism or a fail-safe circuit external to the C Controller module. For a fail-safe circuit
example, refer to "Page 493, Appendix 11".
(3) Outputs may remain on or off due to a failure of an output module relay or transistor. Configure
an external circuit for monitoring output signals that could cause a serious accident.

SAFETY PRECAUTIONS

(Read these precautions before using this product.)
Indicates that incorrect handling may cause hazardous conditions,
resulting in death or severe injury.
Indicates that incorrect handling may cause hazardous conditions,
resulting in minor or moderate injury or property damage.
WARNING
WARNING" and "
CAUTION" may lead to
CAUTION".
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