Wiring; The Precautions On The Wiring - Mitsubishi MELSEC- Q Q12PHCPU User Manual

9 LOADING AND INSTALLATION

9.6 Wiring

9.6.1 The precautions on the wiring

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Completely turn off the external power supply when installing or
DANGER
placing wiring. Not completely turning off all power could result in
electric shock or damage to the product.
When turning on the power supply or operating the module after
installation or wiring work, be sure that the module's terminal covers are
correctly attached. Not attaching the terminal cover could result in
electric shock.
Be sure to ground the FG terminals and LG terminals to the
CAUTION
protective ground conductor. Not doing so could result in electric
shock or erroneous operation.
When wiring in the PLC, be sure that it is done correctly by checking
the product's rated voltage and the terminal layout. Connecting a
power supply that is different from the rating or incorrectly wiring the
product could result in fire or damage.
External connections shall be crimped or pressure welded with the
specified tools, or correctly soldered. Imperfect connections could
result in short circuit, fires, or erroneous operation.
Tighten the terminal screws with the specified torque. If the terminal screws
are loose, it could result in short circuits, fire, or erroneous operation.
Tightening the terminal screws too far may cause damages to the screws
and/or the module, resulting in fallout, short circuits, or malfunction.
Be sure there are no foreign substances such as sawdust or wiring
debris inside the module. Such debris could cause fires, damage, or
erroneous operation.
The module has an ingress prevention label on its top to prevent
foreign matter, such as wire offcuts, from entering the module during
wiring.
Do not peel this label during wiring.
Before starting system operation, be sure to peel this label because
of heat dissipation.
The precautions on the connection of the power cables are described below.
(1) Power supply wiring
(a) Separate the PLC's power supply line from the lines for I/O devices and
power devices as shown below.
When there is much noise, connect an insulation transformer.
Main power PLC power
supply supply
200VAC
I/O power supply
Main circuit device
Insulation
transformer
PLC
T1
I/O devices
Main circuit device
MELSEC-Q
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