Mitsubishi Electric MELDAS MDS-B-SVJ2 Series - Noise Measures

Chapter 3 Installation
3-10
3-3 Noise measures
Noise includes that which enters the servo amplifier from an external source and causes the servo
amplifier to malfunction, and that which is radiated from the servo amplifier or motor and causes the
peripheral devices or amplifier itself to malfunction. The servo amplifier output is a source of noise as
the DC voltage is switched at a high frequency. If the peripheral devices or amplifier malfunction
because of the noise, measures must be taken to suppressed this noise. These measures differ
according to the propagation path of the noise.
(1) General measures for noise
• Avoid wiring the servo amplifier's power supply wire and signal wires in parallel or in a bundled
state. Always use separate wiring. Use a twisted pair shield wire for the detector cable, the
control signal wires for the bus cable, etc., and for the control power supply wire. Securely
ground the shield.
• Use one-point grounding for the servo amplifier and motor.
(2) Measures against noise entering from external source and causing servo amplifier to
malfunction
If a device generating noise is installed near the servo amplifier, and the servo amplifier could
malfunction, take the following measures.
• Install a surge killer on devices (magnetic contactor, relay, etc.) that generate high levels of
noise.
• Install a data line filter on the control signal wire.
• Ground the detector cable shield with a cable clamp.
(3) Measures against noise radiated from the servo amplifier and causing peripheral devices
to malfunction
The types of propagation paths of the noise generated from the servo amplifier and the noise
measures for each propagation path are shown below.
Noise generated
from servo am
p
lifie
r
Noise directly radiated
from servo am
p
lifie
r
Airborne
propagation noise
Path ①
Noise radiated from
p
ower su
pp
l
y
wire
Magnetic
induction noise
Path ②Path ④
and ⑤
Noise radiated from
servomoto
r
Static induction
noise
Path ③Path ⑥
Noise propagated over
p
ower su
pp
l
y
wire
Cable propagation
noise
Path ⑦
Noise lead in from
grounding wire by
leaka
g
e current
Path ⑧