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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 FP and its ground. If
there is still excess noise, connect an insulating
transformer (noise-prevention type) .
• Wire the power cords of the FP, 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.
• To prevent excessive noise, be sure to make
the power cord as short as possible.
Constant
voltage
transformer
Twisted-pair
cable
FP
FG
Insulating
transformer
Twisted-pair
cable
FP
FG
Main power
source
FP
power
source
T1
T2
I/O power
source
FP
I/O
device
Main circuit
power source
Power
device
AC 100V
to AC200V
• Ground the lightning surge ab-
sorber (E1) and the FP (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 to
AC200V
FP
power
source
I/O power
source
F P
I/O device
Main
power
source
When connecting the FP unit’s AC power terminals, please be aware of the follow-
ing:
Be sure any constant or insulating
transformer used has a capacity of
100VA or more.
Twisted-pair
cable
FP
FG
Lightning surge
absorber
AC
E1
E2
I/O
device