Sperian Biosystems NXP, Справочное руководство

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18
3. Field Usage
Once the NXP has been installed and
connected to a power source, it will run
through a boot-up process, and then be in
continuous operation. During the boot-up
process, the following information will be
shown on the display:
•
Power supply voltage
•
LCD Test (All Segments On)
•
Firmware Version
•
“NEP” (Indicates Non-Explosion-
Proof Instrument)
•
Sensor Type
•
Loop Range (See Section 5.4)
•
Instrument Serial Number
•
Warning and Danger Alarm Levels
•
Calibration reminder (if set)
•
Bump Test reminder (if set)
•
10-second countdown
Gas readings are shown on the display on
the front of the detector. Toxic gas
readings are normally displayed in parts-
per-million (PPM), oxygen readings are
given in terms of percent volume (%Vol),
and combustible gas readings are given in
either percent LEL (LEL), or percent
volume methane (CH
4
).
3.1 Modes of operation
Press the MODE button to scroll through
the screens. The current gas reading
screen is shown during normal operation.
Detector heads equipped with toxic gas
sensors will display gas readings in parts-
per-million (PPM). Some sensors will
resolve readings to tenths of a part per
million.
Detector heads equipped with oxygen
sensors display readings in percent-by-
volume. Fresh air contains 20.9% oxygen
by volume.
Detector heads equipped with
combustible gas sensors can display
readings in terms of either percentage of
the Lower Explosive Limit (%LEL) or
percent methane by volume (%CH4).
A reading of 100%
LEL or 5% CH4 indicates a potentially
explosive environment.
From the current gas readings screen,
press the MODE button once to view the
MAX reading screen. The MAX readings
screen displays the highest reading that
has been recorded by the instrument in
the past 24 hours.