Oriental motor BLV Series - Motor Operation and Stop Control

Connection
33
6-8 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 aected 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.
z
Noise suppression
•
When relays or electromagnetic switches are used, use noise lters or CR circuits to suppress surge generated by
them.
•
Use a connection cable (sold separately) when extending the wiring distance between the motor and the driver.
This is eective in suppressing the electrical noise emitted from the motor.
•
Cover the driver by a metal plate such as aluminum. This is eective in shielding the electrical noise emitted from
the driver.
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Prevention of noise propagation
•
Place the power lines such as the motor and power supply cables, keeping a distance of 100 mm (3.94 in.) or more
from the signal lines such as I/O signal cable and RS-485 communication cable, and also do not bundle them or
wire them in parallel. If a power cable and a signal cable have to cross, cross them at a right angle.
•
Use a cable of AWG 26 (0.14 mm
2
) or thicker for the I/O signal cable.
•
Use a cable of AWG 26 (0.14 mm
2
) or thicker for the RS-485 communication cable.
•
Use the CAN-Bus cable for the CAN communication cable.
•
For more eective elimination of noise, use shielded cables for a power supply cable and a signal cable or install
ferrite cores if non-shielded cables are used.
•
Keep cables as short as possible without coiling and bundling extra lengths.
•
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
•
Grounding multiple points will increase eect to block electrical noise because impedance on the grounding
points is decreased.
However, ground them so that a potential dierence does not occur among the grounding points.
z
Suppression of eect 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 eect 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 eect of noise
attenuation by the ferrite core, loop the cable a lot.