Riken Keiki RS-400 Series, Руководство по эксплуатации

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3 How to Connect Wire 3-5. Precautions on electrical work
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Introducing protective measures against lightning
If cables are installed outside the factory/plant, or if internal cables are installed in the same duct as the
cables coming from outside the factory/plant, "inductive lightning surge" may be caused by lightning.
Because lightning acts as a large emission source while cables act as a receiving antenna, devices
connected to the cables may be damaged.
The occurrence of lightning cannot be prevented, and even cables installed in a metal conduit or under the
ground cannot be completely protected from inductive lightning surge caused by lightning.
Although complete elimination of damages caused by lightning is impossible, the following protective
measures can be taken.
Protection against
lightning
Take appropriate measures in accordance with the importance of the facilities
and the environment.
Provide protection by a lightning arrester (cable arrester).
Install a lightning arrester before the field devices and central processing
equipment to mitigate any risk due to inductive lightning surge transmitted
through the cable. For information on how to use a lightning arrester, please
contact the manufacturer.
Grounding
In addition to lightning, there are more sources of surge noise. To protect devices
from these noise sources, the devices must be grounded.
* The lightning arrester has a circuit to remove a surge voltage which damages field devices.
Therefore, signals may be attenuated by installing the arrester. Before installing a lightning
arrester, verify that it works properly.