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1. Installation
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1-5 Noise measures
Noise includes "propagation noise" generated from the power supply or relay, etc., and propagated
along a cable causing the power supply unit or drive unit to malfunction, and "radiated noise"
propagated through air from a peripheral device, etc., and causing the power supply unit or drive unit to
malfunction.
Always implement these noise measures to prevent the peripheral devices and unit from malfunctioning.
The measures differ according to the noise propagation path, so refer to the following explanation and
take appropriate measures.
(1) General noise measures
• Avoid laying the drive unit's power line and signal wire in a parallel or bundled state. Always
separate these wires. Use a twisted pair shielded wire for the detector cable and signal wires
such as the communication cable connected with the NC, and accurately ground the devices.
• Use one-point grounding for the drive unit and motor.
• Accurately ground the AC reactor.
(2) Propagation noise measures
Take the following measures when noise generating devices are installed and the power supply
unit or drive unit could malfunction.
• Install a surge killer on devices (magnetic contacts, relays, etc.) which generate high levels of
noise.
• Install a power line filter in the stage before the power supply unit.
• Install a ferrite core on the signal wire.
• Ground the shield of the servo detector's cable with a cable clamp.
• Wire the spindle PLG detector cable away from other wires.
(3) Measures against radiated noise
The types of propagation paths of the noise and the noise measures for each propagation path are
shown below.
Noise generated from
drive unit
Noise directly radiated
from drive unit
Airborne
propagation noise
Path [1]
Noise radiated from
power line
Magnetic induction
noise
Path [2]
Path [4]
and [5]
Noise radiated from
servomotor/spindle motor
Static induction
noise
Path [3]Path [6]
Noise propagated over
power line
Cable propagation
noise
Path [7]
Noise lead in from
grounding wire by
leakage current
Path [8]