6 Wiring
6.4.2 Wiring for Noise Control
6-20
6.4.2 Wiring for Noise Control
(1) Wiring Example
The SERVOPACK uses high-speed switching elements in the main circuit. It may receive “switching noise”
from these high-speed switching elements if the processing of wiring or grounding around the SERVOPACK is
not appropriate. To prevent this, always wire and ground the SERVOPACK correctly.
The SGDH SERVOPACK has a built-in microprocessor (CPU), so protect it from external noise as much as pos-
sible by installing a noise filter in the appropriate place.
The following is an example of wiring for noise control.
(2) Correct Grounding
(a) Grounding the Motor Frame
Always connect servomotor frame terminal FG to the SERVOPACK ground terminal
. Also be sure to
ground the ground terminal
.
If the servomotor is grounded via the machine, a switching noise current will flow from the SERVOPACK
power unit through servomotor stray capacitance. The above grounding is required to prevent the adverse
effects of switching noise.
(b) Noise on the Reference Input Line
If the reference input line receives noise, ground the 0 V line (SG) of the reference input line. If the main cir-
cuit wiring for the motor is accommodated in a metal conduit, ground the conduit and its junction box.
For all grounding, ground at one point only.
For ground wires connected to the casing, use a thick wire with a thickness of
at least 3.5 mm (0.005 in ) (preferably, plain stitch cooper wire)
2
: represents twisted-pair wires.
When using a noise filter, follow the precautions in
6.4.2 Wiring for Noise Control
(3) Using Noise Filter.
U
W
V
L2
L1
L3
L2C
L1C
CN2
CN1
SERVOPACK
Servomotor
Operation relay
sequence
Signal generation
circuit (provided by
customer)
1LF
AVR
(Ground)
(Casing)
(Casing)
(Casing)
2
(Casing)
(Ground plate)
2LF
3.5 mm
(0.005 in )
min.
2
200 VAC
Noise filter
∗
3
∗
3
∗
1
∗
1
∗
2
∗
3
∗
1
∗
2
2 mm
2
(0.003 in ) min.
3.5mm (0.005 in ) min.
2
∗
1
2.0 mm
2
(0.003 in )
min .
3.5mm
(0.005 in )
min.
2
PG
(FG)
M
2
2
Wires of 3.5 mm
(0.005 in ) or more
2
2
2
Ground: Ground to an independent ground
(at least class-3 grounding (100
Ω
max).)
2
2
Summary of Contents for SGDH
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