Mitsubishi Electric Melsec Q Series User Manual page 4

Precautions for using the MELSEC-Q series Ethernet interface
module
[Design Precautions]
 For the operating status of each station after a communication failure, refer to relevant manuals
for the network. Erroneous outputs and malfunctions may lead to accidents.
Not doing so can cause an accident due to false output or malfunction.
 To prevent the malfunction of the programmable controller system due to harmful e-mails, take
preventive measures (such as antivirus measures) so that the mail server for this module does
not receive harmful e-mails.
 To maintain the safety of the programmable controller system against unauthorized access from
external devices via the Internet, take appropriate measures.
 When connecting a peripheral with the CPU module or connecting an external device, such as a
personal computer, with an intelligent function module to modify data of a running
programmable controller, configure an interlock circuit in the program to ensure that the entire
system will always operate safely.
For other forms of control (such as program modification or operating status change) of a
running programmable controller, read the relevant manuals carefully and ensure that the
operation is safe before proceeding.
Especially, when a remote programmable controller is controlled by an external device,
immediate action cannot be taken if a problem occurs in the programmable controller due to a
communication failure.
To prevent this, configure an interlock circuit in the program, and determine corrective actions to
be taken between the external device and CPU module in case of a communication failure.
 Do not write any data to the "system area" of the buffer memory in the intelligent function
module.
Also, do not use any "use prohibited" signals as an output signal from the programmable
controller CPU to the intelligent function module.
Doing so may cause malfunction of the programmable controller system.
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WARNING
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