Safety Precautions; Design Precautions - Mitsubishi Electric Q12DCCPU-V 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.
The precautions given in this manual are concerned with this product only. For the safety precautions of the
programmable controller system, refer to the user's manual for the CPU module used.
In this manual, the safety precautions are classified into two levels: "
WARNING
CAUTION
Under some circumstances, failure to observe the precautions under "
consequences.
Observe the precautions of both levels because they are important for personal and system safety.
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 self-
diagnostic 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 "CHAPTER 6
PREPARATORY PROCEDURES AND SETTING" in this manual.

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" and "
WARNING
CAUTION".
CAUTION" may lead to serious
A
- 1