Omron 3G3MV-PDRT2, User Manual

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Chapter 3
3-23
Setup and Wiring
• Ground the shielding wire on the communications cable at one point.
• If the same ground is used for the communications cables and communications power supply, there
is a possibility that noise may be transmitted through the ground line to the communications line. In
order to avoid this, be sure that the power line ground and the grounds for the communications
cables and the communications power supply are located as far from each other as possible.
!Caution Connect the communications signal lines (V+, CAN H, shield, CAN L, and V
−
) so
that they do not come into contact with each other.
If noise is generated, check the wiring.
• Communications may be performed even if the V+ and CAN H, or V
−
and CAN L, are in contact
with each other, but differential operation will not be performed, reducing resistance to noise.
• If the shield wire comes into contact with any of the signal lines, a high level of noise will be
superimposed on the line, reducing resistance to noise.
3-3-5 Noise Prevention for Peripheral Devices
• Install surge suppressors on devices that generate noise, particularly devices that have an induc-
tive component such as motors, transformers, solenoids, and magnetic coils.
• If a surge suppressor does not fit on the device, installing a ferrite core directly next to the device's
contactors, such as a contactor may be effective.
• Insert a line filter on the primary side of the communications power supply.
• When there are two or more communications power supplies, the communications power cables
can be grounded by simply connecting a single Power Supply Tap near the center of the communi-
cations cable. Do not ground shielding wire at more than one place.
Surge suppressor
(Installed next to device)
DC input type
Device (such as a motor)
AC input type
Surge suppressor
(Installed next to device)
Device (such as a motor)
Ferrite core 0443-164151
Nisshin Electric Co, Ltd.
Device (such as a motor)