Mitsubishi MELSEC-Q Series User Manual page 4

[Design Precautions]
If load current more than the rating or overcurrent due to a short circuit in the load has flowed in the
output module for a long time, it may cause a fire and smoke. Provide an external safety device
such as a fuse.
Create the circuit so that the external power supply will turn on after the C Controller system is
powered on.
Turning on the external power supply first could result in accidents due to erroneous output or
operation.
For each station's operating status in the event of a each station error, refer to the corresponding
each station manual.
Not doing so could result in erroneous output or operation.
When controlling a running C Controller module (data modification) by connecting a personal
computer to the C Controller module, create an interlock circuit on user programs so that the whole
system functions safely all the time.
This must be also done when performing any other controls (e.g. operating status change (status
control)) or operations instructed from the computer.
In these controls, especially the one performed from an external device to a C Controller module in a
remote location, some C Controller side problem may not be resolved immediately due to failure of
data communications.
To prevent this, create an interlock circuit on user programs and establish corrective procedures for
communication failure between the external device and the C Controller module.
When setting up the system, do not allow any empty slot on the base unit.
If any slot is left empty, be sure to use a blank cover (QG60).
Otherwise, in the short circuit test or when an overcurrent or overvoltage is accidentally applied to
the external I/O section, internal parts of the module may be flied.
Do not install the control wires or communication cables together with the main circuit or power
wires, or bring them close to each other.
Keep a distance of 100 mm (3.94 inch) or more between them.
Not doing so could result in malfunctions due to noise.
When controlling a lamp, heater or solenoid valve using an output module, large current
(approximately ten times greater than in normal conditions) may flow when the output is turned ON
from OFF.
Take preventive measures such as replacing the module with the one having sufficient rated current.
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CAUTION