4
[Design Precautions]
[Security Precautions]
CAUTION
● Do not install the control lines or communication cables together with the main circuit lines or power 
cables. Doing so may result in malfunction due to electromagnetic interference. Keep a distance of 
100mm or more between those cables.
● 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 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 and SD memory card undefined. The values 
need to be set in the buffer memory and written to the flash ROM and SD memory card 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 by Program" for "Opening Method" of "Module 
Parameter". If "Open by 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.
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.