15
7
Power Supply Cautions
• If voltage fluctuations are expected to vary
beyond the specified range, connect a constant
voltage transformer.
• Use a low-noise power supply both between
the lines and between the PL and its ground.
If there is still excess noise, connect an insulat-
ing transformer (noise-prevention type) .
• Wire the power cords of the PL, I/O devices,
and power supply devices separately.
• To improve noise immunity, it is recom-
mended to attach a ferrite core to the power
cord.
• Isolate the main circuit (high voltage, large
current) line, I/O signal lines, and power cord,
and do not bind or group them together.
• To prevent damage from lightning, connect a
lightning surge absorber.
Constant
voltage
transformer
Twisted-pair
cable
PL
FG
Insulating
transformer
Twisted-pair
cable
PL
FG
Main power
source
PL power
source T1
T2
I/O power
source
PL
I/O
device
Main circuit
power source
Power
device
AC 200V
• Ground the lightning surge ab-
sorber (E1) and the PL (E2) sepa-
rately.
• Select a lightning surge absorber
which will not exceed the allow-
able circuit voltage, even when
the voltage rises to the maximum.
AC100V
PL power
source
I/O power
source
PL
I/O device
Main power
source
When connecting the PL unit’s AC power terminals, please be aware of the
following:
Be sure any constant or insulating
transformer used has a capacity of
200VA or more.
Twisted-pair
cable
PL
FG
Lightning surge absorber
AC
E1
E2
I/O
device