Mitsubishi Electric MR-J4W2-0303B6 Instruction Manual page 278

11. OPTIONS AND PERIPHERAL EQUIPMENT
(1) Noise reduction techniques
(a) General reduction techniques
Avoid laying power lines (input and output cables) and signal cables side by side or do not bundle
them together. Separate power lines from signal cables.
Use a shielded twisted pair cable for connection with the encoder and for control signal
transmission, and connect the external conductor of the cable to the SD terminal.
Ground the servo amplifier, servo motor, etc. together at one point. (Refer to section 3.11.)
(b) 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.
(c) Techniques for noises radiated by the servo amplifier that cause peripheral devices 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 devices located near the main
circuit cables, and those transmitted through the power supply cables.
Noises produced
by servo amplifier
Noises transmitted
in the air
Magnetic induction
Routes 4) and 5)
noise
Static induction
Route 6)
noise
Noises transmitted
through electric
channels
11 - 33
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
Route 1)
Route 2)
Route 3)
Route 7)
Route 8)