Omron OMNUC FND Series User Manual page 106

Design and Installation
The following table shows the Servomotor leakage currents for each Position Driver.
Driver
FND-X06 /X12
FND-X25
FND-X50H
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 room temperature and humidity. The values will change
depending on the temperature and humidity.
j Improving Encoder/Resolver Cable Noise Resistance
Signals from the encoder are either A, B, or S phase. The frequency for A- or B-phase signals is 154 kHz
and the transmission speed for S-phase signals is 616 kbps. The Resolvers use analog voltage signals.
Follow the wiring methods outlined below to improve encoder/resolver noise resistance.
Be sure to use dedicated encoder/resolver cables.
If lines are interrupted in the middle, connect them with connectors, making sure that the cable insula-
tion 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 clamp filters. The following table shows the rec-
ommended clamp filter models. Do not use these with resolver cables.
Do not wire the encoder/resolver cable in the same duct as power cables and control cables for
brakes, solenoids, 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.
If the control power supply wiring is long, noise resistance can be improved by adding 1-µF laminated
ceramic capacitors between the control power supply and ground at the Position Driver input section
and the controller output section.
Use twisted-pair shielded cables for control cables, and the shield wire to the connector frame at the
Position Driver.
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Leakage current (resistor)
(including high-frequency current)
35 mA
0-P
40 mA
0-P
120 mA
0-P
Chapter 2
Leakage current (resistor-capacitor,
in commercial power supply fre-
quency range)
2 mA
rms
2 mA
rms
3 mA
rms