Mitsubishi Electric MELSEC iQ-R Series User Manual page 5

[Design Precautions]
WARNING
● Do not write any data to the "system area" and "write-protect area" of the buffer memory in the
module. Also, do not use any "use prohibited" signals as an output signal from the CPU module to
each module. Doing so may cause malfunction of the programmable controller system. For the
"system area", "write-protect area," and the "use prohibited" signals, refer to the user's manual for the
module used.
● If a communication cable is disconnected, the network may be unstable, resulting in a communication
failure of multiple stations. Configure an interlock circuit in the program to ensure that the entire
system will always operate safely even if communications fail. Failure to do so may result in an
accident due to an incorrect output or malfunction.
[Design Precautions]
CAUTION
● Do not install the control lines or communication cables together with the main circuit lines or power
cables. Keep a distance of 100mm or more between them. Failure to do so may result in malfunction
due to noise.
● During control of an inductive load such as a lamp, heater, or solenoid valve, a large current
(approximately ten times greater than normal) may flow when the output is turned from OFF to ON.
Therefore, use a module that has a sufficient current rating.
● After the CPU module is powered OFF and ON or is reset, the time taken to enter the RUN status
varies depending on the system configuration, parameter settings, and/or program size. Design
circuits so that the entire system will always operate safely, regardless of the time.
● Do not power OFF the programmable controller or reset the CPU module while the settings are being
written. Doing so will make the data in the flash ROM undefined. The values need to be set in the
buffer memory and written to the flash ROM again. Doing so also may cause malfunction or failure of
the module.
● When changing the operating status of the CPU module from external devices (such as the remote
RUN/STOP functions), select "Do Not OPEN in Program" for "Open Method Setting" in the module
parameters. If "OPEN in Program" is selected, an execution of the remote STOP function causes the
communication line to close. Consequently, the CPU module cannot reopen the line, and external
devices cannot execute the remote RUN function.
[Security Precautions]
WARNING
● To maintain the security (confidentiality, integrity, and availability) of the programmable controller and
the system against unauthorized access, denial-of-service (DoS) attacks, computer viruses, and other
cyberattacks from external devices via the network, take appropriate measures such as firewalls,
virtual private networks (VPNs), and antivirus solutions.
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