RKI Instruments GD-70D Series, Руководство по эксплуатации

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GD-70D
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4-3 Precautions for System Designing
Using a stable power supply
The external output and alarm contact of the detector may be activated when the power is turned on, when
momentary blackout occurs, or when the system is being stabilized. In such cases, use a safety power
supply, or take appropriate actions on the receiving side.
The detector must be provided with the following power supply.
Power supply voltage
24 VDC
±
10% (the terminal voltage of the detector)
or PoE connection (GD-70D-
EA)
Allowed time of
momentary blackout Up to 10 milliseconds (To
recover from a momentary
blackout longer than 10
milliseconds, restart the
detector.) Example of actions
To ensure continuous operation and activation, install
a protective power supply outside the detector.
Others Do not use it with a power
supply that has a large
power load or high-
frequency noise. Example of actions
Use a line filter to avoid the noise source if
necessary.
Heat radiation designing
When it is installed in the closed instrumentation board, attach ventilation fans above and below the board.
Protecting 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, lightning will cause problems. Because lightning acts as a
large emission source while cables act as a receiving antenna, devices connected to the cables may be
damaged.
Lightning cannot be prevented. Cables installed in a metal conduit or under the ground cannot be
completely protected from a power surge caused by lightning. Although complete elimination of disasters
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.
•
Connect the transmission signal route by using optical fiber.
•
Provide protection by a lightning arrester (cable safety retainer).
(Although inductive lightning surge can be transmitted through the cable, it
is prevented by installing a lightning arrester before the field devices and
central processing equipment. 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, so that
signals may be attenuated. Before installing a lightning arrester, verify that it works properly.
CAUTION
•
An unstable power supply and noise may cause malfunctions or false alarms.