2-28
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-V
AC-input Servomotors is approximately half that of the values shown above.
j Improving Encoder Cable Noise Resistance
Signals from the encoder are either A, B, or S phase. The frequency for A- or B-phase signals is
76.8 kHz
max., while the transmission speed for S-phase signals
is 307 kbps. Follow the wiring meth
-
ods 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 af
fected 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 12 to 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.
• Use
separate power supplies for control power and for power for the pulse command and deviation
counter
reset input lines. Do not connect the ground wires for these two power supplies to the same
ground.
• We recommend line drivers for the pulse command and deviation counter reset outputs.
• For
the pulse command and
deviation counter reset 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.
• Wiring must be 1 m or less when using open-collector outputs.
System Design and Installation
Chapter
2
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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