Mitsubishi Electric MELSEC iQ-R Series User Manual page 5

[Design Precautions]
WARNING
● 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. Incorrect output or malfunction due to a
communication failure may result in an accident.
● 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.
[Precautions for using C Controller modules]
● In the refresh parameter setting, 'Y' cannot be specified for a link output (LY) refresh device or a
remote output (RY) refresh device. Therefore, C Controller module holds the device status as is even
after the module status is changed to STOP.
[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 OFF and ON.
Therefore, use a module that has a sufficient current rating.
● After the power is turned OFF and ON or the CPU module 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 turn the power OFF 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 may cause malfunction or failure of the module.
● When changing the operating status of the CPU module from external devices (such as 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 remote STOP causes the
communication line to close. Consequently, the CPU module cannot reopen the communication line,
and the external device cannot execute the remote RUN.
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