Mitsubishi Electric MELSEC-L SSCNETIII/H User Manual page 4

[Design Precautions]
● In an output circuit, 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.
● Configure a circuit so that the external power supply is turned off first and then the programmable
controller. If the programmable controller is turned off 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 relevant manuals for
each network. Incorrect output or malfunction due to a communication failure may result in an
accident.
● When connecting a peripheral with the head 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 of the Motion controller to ensure that the entire
system will always operate safely.
For other controls to a running programmable controller (such as program modification of the Motion
controller or operating status change), read relevant manuals carefully and ensure the safety before
the operation. 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 of the Motion
controller, and determine corrective actions to be taken between the external device and head module
in case of a communication failure.
● The optical transmitter and receiver of the head module use laser diodes (class 1 in accordance with
IEC 60825-1). Do not look directly at a laser beam. Doing so may harm your eyes.
[Design Precautions]
● 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 head module is powered on or is reset, the time taken to enter the RUN status varies
depending on the system configuration and/or parameter settings. Design circuits so that the entire
system will always operate safely, regardless of the time.
2
WARNING
CAUTION