Mitsubishi Electric MELSEC L Series User Manual page 149

(b) Noise filter (power supply line filter)
A noise filter is effective for reducing conducted noise in the 10MHz or less frequency band. (Use of a noise
filter can suppress noise.)
The following are the installation precautions.
(c) Isolation transformer
An Isolation transformer is effective for reducing conducted noise (especially, lightning surge). Lightning surge
may cause malfunction of the programmable controller. As measures against lightning surge, connect an
isolation transformer as shown below. Use of an isolation transformer can reduce a lightning effect.
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• Do not bundle the cables on the input side and output side of the noise filter. If bundled, the noise on the
output side is induced into the filtered cable on the input side.
Input side
(power supply side)
Filter
Output side
(device side)
Noise will be induced when the input
and output cables are bundled.
• Ground the ground terminal of the noise filter to the ground point of the control panel with the shortest
cable possible (approximately 10cm).
Main
power
supply
100VAC
200VAC
Inside a control panel
search engine
Input side
(power supply side)
Induction
Separately install the input and
output cables.
Programmable
Relay
Isolation
terminal controller
transformer
block power supply
I/O power T1
supply
Motor power
supply
Filter
Output side
(device side)
Programmable
controller
I/O equipment
Motor equipment
APPENDICES
A
147