Mitsubishi Electric MELSERVO-J4 Series Instruction Manual page 419

■Reduction techniques for external noises that cause the servo amplifier to malfunction
If there are noise sources (such as a magnetic contactor, an electromagnetic brake, and many relays which make a large
amount of noise) near the servo amplifier and the servo amplifier may malfunction, the following countermeasures are
required.
• Provide surge absorbers on the noise sources to suppress noises.
• Attach data line filters to the signal cables.
• Ground the shields of the encoder connecting cable and the control signal cables with cable clamp fittings.
• Although a surge absorber is built into the servo amplifier, to protect the servo amplifier and other equipment against large
exogenous noise and lightning surge, attaching a varistor to the power input section of the equipment is recommended.
■Techniques for noises radiated by the servo amplifier that cause peripheral equipment to
malfunction
Noises produced by the servo amplifier are classified into those radiated from the cables connected to the servo amplifier and
its main circuits (input and output circuits), those induced electromagnetically or statically by the signal cables of the
peripheral equipment located near the main circuit cables, and those transmitted through the power supply cables.
Noises produced
by servo amplifier
7)
Instrument Receiver
Noises transmitted
in the air
Magnetic induction
Routes 4) and 5)
noise
Static induction
Route 6)
noise
Noises transmitted
through electric
channels
5)
7)
2)
1)
Servo
amplifier
3)
6)
4)
Servo motor M
Noise radiated directly
from servo amplifier
Noise radiated from the
power supply cable
Noise radiated from
servo motor cable
Noise transmitted through
power supply cable
Noise sneaking from
grounding cable due to
leakage current
7)
Sensor
power
supply
2)
8)
Sensor
3)
11 OPTIONS AND PERIPHERAL EQUIPMENT
11.14 Noise reduction techniques
Route 1)
Route 2)
Route 3)
Route 7)
Route 8)
11
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