Noise Measures - Mitsubishi Electric MDS-E Series Instruction Manual

MDS-E/EH Series Instruction Manual
1 Installation

1.6 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
(a) 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 encoder cable and signal wires such as the communication
cable connected with the NC unit, and accurately ground the devices.
(d) Ground the shield of the servo encoder's cable with a cable clamp.
(c) 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.
(a) Install a surge killer on devices (magnetic contacts, relays, etc.) which generate high levels of noise.
(b) Install a power line filter in the stage before the power supply unit.
(c) Install a ferrite core on the signal wire.
(d) Ground the shield of the servo encoder's cable with a cable clamp.
(e) Wire the spindle PLG encoder 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
Airborne
propagation noise
Magnetic induction
Path [4]
noise
and [5]
Static induction
Path [6]
noise
Cable propagation
noise
43
Noise directly radiated
Path [1]
from drive unit
Noise radiated from
Path [2]
power line
Noise radiated from
Path [3]
servo motor/spindle motor
Noise propagated over
Path [7]
power line
Noise lead in from
Path [8]
grounding wire by
leakage current
IB-1501229-F