Noise Measures - Mitsubishi Electric MELDAS MDS-R Series Technical Specification And Instruction Manual

6-3 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. causing the power supply unit or drive unit to
malfunction.
If the peripheral devices or units malfunction due to this noise, measures must be taken to suppress the
noise. The measures differ according to the noise propagation path, so refer to the following explanations
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 unit. 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 contactors, relays, etc.) which generate high levels of
noise.
• Install a power supply filter.
• Mount a ferrite core on the signal wire.
• Ground the shield of the servo detector's cable with a cable clamp fittings.
(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
6. Installation
Airborne
propagation noise
Magnetic
Path
induction noise
<4>and<5>
Static induction
Path <6>
noise
Cable propagation
noise
6 - 15
Noise directly radiated
Path <1>
from drive unit
Noise radiated from
Path <2>
power line
Noise radiated from
Path <3>
servomotor/spindle
motor
Noise propagated over
Path <7>
power line
Noise lead in from
Path <8>
grounding wire by
leakage current