Mitsubishi MELSEC-A Series Reference Manual page 3

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 save this manual to make it accessible when required and always forward it to the end user.
[DESIGN PRECAUTIONS]
Refer to this manual for each station's operating status when a communication error occurs in the
network. Erroneous operation may result in accidents.
When controlling a running programmable controller (data modification) by connecting a peripheral
device or GX Developer to a CPU module or by connecting a PC to a special function module, create
an interlock circuit in the sequence program so that the entire system will function safely all the time.
Also, before performing any other controls (e.g. program modification, operating status change
(status control)), read the relevant manual(s) carefully to ensure the safety.
Especially in control from an external device to a programmable controller in a remote location, some
programmable controller side problem may not be resolved immediately due to failure of data
communications.
To prevent this, create an interlock circuit in the sequence program and set up corrective procedures
to be taken in the event of communication failure between the external device and programmable
controller CPU.
Do not bundle the control wires and communication cables with the main circuit or power wires, or
install them close to each other. They should be installed at least 100mm (3.94inch) away from each
other. Failure to do so may generate noise that may cause malfunctions.
SAFETY PRECAUTIONS
(Be sure to read these instructions before use.)
Indicates that incorrect handling may cause hazardous conditions,
resulting in death or severe injury.
Indicates that incorrect handling may cause hazardous conditions,
resulting in medium or slight personal injury or physical damage.
DANGER
CAUTION
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