Safety Precautions - Mitsubishi MELSEC-Q Series User Manual

Before using this product, please read this manual and the relevant manuals introduced in this manual
carefully and pay full attention to safety to handle the product correctly.
The instructions given in this manual are concerned with this product. For the safety instructions of the
programmable controller system, please read the CPU module user's manual.
In this manual, the safety instructions are ranked as "DANGER" and "CAUTION".
DANGER
CAUTION
Note that the CAUTION level may lead to a serious consequence according to the circumstances.
Always follow the instructions of both levels because they are important to personal safety.
Please keep this manual in a safe place for future reference and also pass this manual on to the end user.
[Design Precautions]
Provide a safety circuit outside the C Controller module to ensure that the entire system will operate
safely even if an external power failure or C Controller module failure occurs.
Failure to do so could result in accidents due to erroneous output or operation.
(1) For an emergency stop circuit, protection circuit and interlock circuit that is designed for
incompatible actions such as forward/reverse rotation or for damage prevention such as the
upper/lower limit setting in positioning, any of them must be provided outside the C Controller
module.
(2) When the C Controller module detects the following conditions, it will disable the output (Y) from
the user program and writing to buffer memory in the case of both (a) and (b) and turn off all
outputs for (b).
Whether to hold or clear all the outputs is set by a parameter.
(a) The overcurrent protector or overvoltage protector of the power supply module is activated.
(b) An error such as a watchdog timer error is detected by the self-diagnostic function of the C
Controller module.
If an error occurs in I/O control parts and the C Controller module cannot detect the error, all the
outputs may turn ON.
Provide a fail-safe circuit or a preventive mechanism outside the C Controller module so that
machines will operate safely in such a case. For fail-safe circuit examples, refer to "Chapter 5
SETTINGS AND PROCEDURES BEFORE OPERATION" in this manual.
(3) Output could be left on or off when there is a fault in an output module relay or transistor.
So build an external monitoring circuit that will monitor any output signal that could cause serious
accidents.

SAFETY PRECAUTIONS

(Always read these instructions 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 personal injury or physical damage.
DANGER
A
- 1