Fuji Electric MICREX-SX series SPF - Control Panel Mounting (Protection against Noise)

4-3
Section 4 Installation and Wiring
4-1-3 Control panel mounting (protection against noise)
The SPF series products are especially immure to noise pickup. However, it is always recommended to take the following
measures to further enhance system reliability.
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1 Noise via power-supply terminals
• Lightning surge
• Internal surge (switching surge)
1) An isolation transformer should be used.
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Twisted pair wires should be used between the noise
filter and power-supply terminals of the PLC.
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4 Noise via ground of the secondary coils of a transformer • The secondary side of the isolation transformer should
not be grounded as shown in the above ltem 1.
2) An isolation transformer should be used.
PLC
Electrostatic shielding
(to reduce the stray capacitance
between the primary and
secondary coils)
Device
Cabinet
Surge absorber
(FUJI Z-trap)
Power
supply
Example: FUJI FHF-type
power filter
PLC
Noise filter
Other device
Other device
PLC
Common ground must not be used.
Other device
Other device
Type D (Class 3) grounding
(ground resistance of
100Ω or less)
PLC