2-39
Note 1. Leakage current values shown above are for motor power lines of 10 m or less. The values will
change depending on the length of power cables and the insulation.
Note 2. Leakage current values shown above are for normal temperatures and humidity. The values
will change depending on the temperature and humidity.
Note 3. Leakage current for 100-VAC-input Servomotors is approximately half that of the values
shown above.
j
Improving Encoder Cable Noise Resistance
The following encoder signals are used: A, B, and S phase. The frequency for A- or B-phase signals is
154 kHz max.; the transmission speed for S-phase signals is 616 kbps.
Follow the wiring methods outlined below to improve encoder noise resistance.
•
Be sure to use dedicated encoder cables.
•
If lines are interrupted in the middle, be sure to connect them with connectors, making sure that the
cable insulation is not peeled off for more than 50 mm. In addition, be sure to use shielded wire.
•
Do not coil cables. If cables are long and are coiled, mutual induction and inductance will increase and
will cause malfunctions. Be sure to use cables fully extended.
•
When installing noise filters for encoder cables, use ferrite cores. The following table shows the rec-
ommended ferrite core models.
Maker
Name
Model
Tokin
EMI core
ESD-QR-25-1
TDK
Clamp filter
ZCAT2032-0930
ZCAT3035-1330
ZCAT2035-0930A
•
Do not wire the encoder cable in the same duct as power cables and control cables for brakes, sole-
noids, clutches, and valves.
j
Improving Control I/O Signal Noise Resistance
Position can be affected if control I/O signals are influenced by noise. Follow the methods outlined be-
low for the power supply and wiring.
•
Use completely separate power supplies for the control power supply (especially 24 VDC) and the
external operation power supply. In particular, be careful not to connect two power supply ground
wires. Install a noise filter on the primary side of the control power supply.
•
For speed and torque command input lines, be sure to use twisted-pair shielded cable, and connect
both ends of the shield wire to ground.
•
If the control power supply wiring is long, noise resistance can be improved by adding 1-
µ
F laminated
ceramic capacitors between the control power supply and ground at the Servo Driver input section
and the controller output section.
•
For encoder output (Z phase) lines, be sure to use twisted-pair shielded cable, and connect both ends
of the shield wire to ground.
System Design and Installation
Chapter 2
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