Omron NA5-12W series, Руководство пользователя по оборудованию

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3 Installation and Wiring
NA-series Programmable Terminal Hardware User’s Manual (V117)
3-5
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3-
5-6 Gro
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• Either install the NA Unit a minimum of 200 mm away from high-voltage lines or power lines, or
place the high-voltage lines or power lines in metal tubing and completely ground the metal tubing
to 100
Ω
or less.
Grounding has the following two purposes.
• Protective Grounding
Protective grounding is done to ensure safety. It is intended to prevent electrical shock by holding the
electrical potential at the grounding potential that is generated by factors such as leakage, induction,
or failure.
• Functional Grounding
Functional grounding is done to protect device and system functions, including prevention of noise
from external sources, or prevention of noise from devices or equipment that could have harmful
effects on other devices or equipment.
Grounding requirements sometimes depend on the situation, and they may be found based on experi-
mentation. It is important to sufficiently check the particular circumstances before grounding.

Principles of One-point Grounding
For devices to operate properly, the reference potential between the devices must be stabilized. Use
one-point grounding so that noise current does not flow to ground lines between the devices.
• Use one-point grounding as shown in figure (a). Connect to the ground pole of the other devices.
• Never connect to the same ground as a device that draws a large amount of power, such as a
motor or inverter. Ground the devices separately to avoid mutually adverse influences.
• To prevent electrical shock, do not connect to ground poles (or steel frames) to which multiple
devices are connected.
• Use a ground pole as close to the NA Unit as possible and keep the ground line as short as possi-
ble.
3-5-6 Grounding
Grounding Methods and Precautions
Example: Separating NA Unit from Power Lines
Metal tubing
200 mm
200 mm
High-voltage power panel
Power lines
Power lines
Ground of
100 Ω or less
NA Unit
NA Unit