4 How to Use
4-3. Precautions for system designing
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SD-1DGH-AS
CAUTION
An unstable power supply and noise may cause malfunctions or false alarms.
The descriptions in this section must be reflected on the designing of a system using the detector.
Do not install the detector in a place exposed to direct sunlight or sudden changes in the temperature.
When selecting installation points, avoid a place where it is exposed to direct sunlight or radiant heat
(infrared rays emitted from a high-temperature object), and where the temperature changes suddenly.
Condensation may be formed inside the detector, or the detector cannot adjust to sudden changes in the
temperature.
Keep the detector (and its cables) away from noise source devices.
When selecting installation points, avoid a place where high-frequency/high-voltage devices exist.
Do not install the detector in a place where maintenance of the detector cannot be performed or where
handling the detector involves dangers.
Regular maintenance of the detector must be performed.
Do not install the detector in a place where the machinery must be stopped when maintenance is performed
in its inside, where parts of the machinery must be removed to perform maintenance, or where the detector
cannot be removed because tubes or racks prevent access to it. Do not install the detector in a place where
maintenance involves dangers, for example, near a high-voltage cable.
Do not install the detector in machinery which is not properly grounded.
Before installing the detector in machinery, the machinery must be grounded properly.
Do not install the detector in a place where interference gases exist around it.
The detector must not be installed in a place where interference gases exist around it.
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 while the system is being stabilized. In such cases, use a UPS, or take
appropriate actions on the receiving side of output signals.
The detector must be provided with the following power supply.
Power supply voltage 24 VDC (17 – 26.4 VDC): Terminal voltage of the detector
Allowed time of
momentary blackout
Up to 10 milliseconds
(To recover from the momentary
blackout for 10 milliseconds or more,
restart the detector.)
Example of actions
To ensure continuous operation and
activation, install a UPS outside the
detector.
Others
Do not use it with a power supply of
large power load or high-frequency
noise.
Example of actions
Use a line filter to avoid the noise source
if necessary.
Summary of Contents for PT2-169
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