Mitsubishi Electric QJ71E71-100 User Manual page 4

[Design Precautions]
● For the operating status of each station after a communication failure, refer to manuals relevant to the
network. Incorrect output or malfunction due to a communication failure may result in an accident.
● 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 network, take appropriate measures. To maintain the safety against
unauthorized access via the Internet, take measures such as installing a firewall.
● 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 in 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.
[Design Precautions]
● Do not bundle the control wires and the communication cables with the main circuit and the power
wires, and do not install them close to each other. They should be installed at least 100 mm (3.94 in.)
away from each other. Failure to do so may generate noise that may cause malfunctions.
● When changing the operating status of the CPU module (such as remote RUN/STOP) from the
external device, select "Always wait for OPEN (Communication possible at STOP time)" for the "Initial
timing" setting in the network parameter. The communication line will be closed when "Do not wait for
OPEN (Communications impossible at STOP time)" is selected and the remote STOP is executed
from the external device. Consequently, the CPU module cannot reopen the communication line, and
the external device cannot execute the remote RUN.
2
WARNING
CAUTION