Mitsubishi Electronics Q13UD(E)HCPU ユーザーズマニュアル

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[Design Precautions]
[Design Precautions]
 WARNING
● In an output module, when a load current exceeding the rated current or an overcurrent caused by a 
load short-circuit flows for a long time, it may cause smoke and fire. To prevent this, configure an 
external safety circuit, such as a fuse.
● Configure a circuit so that the programmable controller is turned on first and then the external power 
supply. If the external power supply is turned on first, an accident may occur due to an incorrect output 
or malfunction.
● 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.
● 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 
sequence program, and determine corrective actions to be taken between the external device and 
CPU module in case of a communication failure.
 CAUTION
● Do not install the control lines or communication cables together with the main circuit lines or power 
cables. Keep a distance of 100mm (3.94 inches) or more between them. Failure to do so may result in 
malfunction due to noise.
● When a device such as a lamp, heater, or solenoid valve is controlled through an output module, a 
large current (approximately ten times greater than normal) may flow when the output is turned from 
off to on. Take measures such as replacing the module with one having 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.