Omron OMNUC W Series Manual page 116

Noise Precautions for Peripheral Devices
Implement the following noise precautions for peripheral devices.
• Install surge suppressors on devices that generate noise, particularly devices that have an
inductive component such as motors, transformers, solenoids, and magnetic coils.
Surge suppressor
(Installed next to device.)
DC input type
Device (such as a motor)
• If a surge suppressor does not fit on the device, such as a contactor, installing a ferrite
core directly next to the device's contactors may be effective.
Ferrite Core 0443-164151
(made by Nisshin Electric Co, Ltd.), etc.
• Insert a line filter on the primary side of the communications power supply.
• When there are two or more communications power supplies, the DeviceNet special
cables can be grounded by simply connecting a single Power Supply Tap near the center
of the DeviceNet special cable. Do not ground shield wire at more than one place.
[When There Is One Power Supply]
Master
PS
[When There Are Two or More Power Supplies]
Power Supply Tap
Master
PS
6-19
6.3 Precautions for Communications Line Design
AC input type
T-branch Tap or Power Supply Tap
Slave
Power Supply Tap
Slave
PS
Slave
Ground at only one point.
Surge suppressor
(Installed next to device.)
Device (such as a motor)
Power Supply Tap
PS
6