Orientalmotor aSTEP AZ Series, Руководство пользователя, Страница: 73 / 180

Connection
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3 DC po
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4-8 Noise elimination measures
There are two types of electrical noises: One is a noise to invade into the driver from the outside and cause the driver
malfunction, and the other is a noise to emit from the driver and cause peripheral equipment malfunction.
For the noise that is invaded from the outside, take measures to prevent the driver malfunction. It is needed to take
adequate measures because signal lines are very likely to be affected by the noise.
For the noise that is emitted from the driver, take measures to suppress it.
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Measures against electrical noise
There are the following three methods mainly to take measures against the electrical noise.
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Noise suppression
• When relays or electromagnetic switches are used, use noise filters or CR circuits to suppress surge generated by
them.
• Use our connection cable when extending the wiring distance between the motor and the driver. Check the model
name on p.85. This is effective in suppressing the electrical noise emitted from the motor.
• Cover the driver by a metal plate such as aluminum. This is effective in shielding the electrical noise emitted from
the driver.
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Prevention of noise propagation
• Connect a noise filter to the AC input side of the DC power supply.
• Place the power lines, such as the motor and the power supply cables, keeping a distance of 200 mm (7.87 in.) or
more from the signal lines, and also do not bundle them or wire them in parallel. If a power line and a signal line
have to cross, cross them at a right angle.
• Use shielded twisted pair cables for power cables and signal cables.
• Keep cables as short as possible without coiling and bundling extra lengths.
• Grounding multiple points will increase effect to block electrical noise because impedance on the grounding
points is decreased. However, ground them so that a potential difference does not occur among the grounding
points. I/O signal cables that include a grounding wire are provided in our product line. Check the model name on
p.89.
• To ground a shielded cable, use a metal cable clamp that can maintain
contact with the entire circumference of the shielded cable, and ground
as near the product as possible.
Cable clamp
Shielded cable
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Suppression of effect by noise propagation
• Loop the noise propagated cable around a ferrite core. Doing so will prevent the propagated noise invades into
the driver or emits from the driver. The frequency band in which an effect by the ferrite core can be seen is
generally 1 MHz or more. Check the frequency characteristics of the ferrite core used. When increasing the effect of
noise attenuation by the ferrite core, loop the cable a lot.
• Change the transmission method of pulse signals to the line driver type which is less likely to be affected by
electrical noise. If the pulse signal of the host controller is of the open collector type, use our pulse signal converter
for noise immunity. Check the model name on p.90.
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Noise suppression product
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Noise filter
• Connect a noise filter (or equivalent) in the table on the AC input side of the DC power supply. When a power
supply transformer is used, be sure to connect a noise filter on the AC input side of the power supply transformer.
Doing so will prevent the propagated noise through the power line. Install the noise filter as close to the input
terminals of DC power supply as possible.
Manufacturer Model
SOSHIN ELECTRIC CO., LTD. HF2010A-UPF
Schaffner EMC FN2070-10-06
• Use the AWG18 (0.75 mm
2
) or thicker wire for the input and output cables of the noise filter, and secure firmly
using a cable clamp or others so that the cable does not come off the enclosure.
• Place the input cable as far apart as possible from the output cable, and do not wire the cables in parallel. If the
input and output cables are placed at a close distance or if they are wired in parallel, the noise in the enclosure
affects the power cable through stray capacitance, and the noise suppressing effect will reduce.
• Connect the ground terminal of the noise filter to the grounding point, using as thick and short a wire as possible.
• When connecting a noise filter inside an enclosure, wire the input cable of the noise filter as short as possible.
Wiring in long distance may reduce the noise suppressing effect.