Operation; Lcd Backlight - Extech Instruments AN310-NIST User Manual

Operation
Air Velocity and Air Volume Measurements
1. Switch the meter ON by pressing the POWER
button again to switch the meter OFF.
2. Note that the meter will automatically enter the sleep mode after 20 minutes of inactivity.
To disable this feature: with the meter OFF, press and hold the POWER and the U/mode
buttons for 2 seconds. The LCD will display 'n' as it switches ON. Now the sleep mode is
disabled and the user must press the POWER button momentarily to switch the meter OFF.
3. When the meter is ON, the upper display can indicate
air velocity or relative humidity (use the U/mode button
to toggle). The lower display digits can indicate air flow,
dew point temperature, wet bulb temperature, or air
temperature (use the L/mode button to scroll).
4. Place the sensor in the air stream. The air must enter
the vane from the rear of the meter. The Air
Temperature and Relative humidity sensors are located at the center of the vane on the rear
of the meter.
5. Read the measurement data on the LCD. Air velocity readings are indicated in meters per
second (m/s) or feet per minute (fpm). Temperature readings (air, dew point, or wet bulb)
are indicated in °C/°F. Relative Humidity is indicated in %. Air flow (volume) is indicated in
CFM (cubic feet per minute) or CMM (cubic meters per minute). Use the L/mode button (for
lower display) and the U/mode button (for upper display) to scroll through the displayed
reading options.
6. To change between Imperial and Metric units of measure refer to the SETUP Mode section.
7. To measure the Air Volume of a duct, first measure the duct's area (see the Appendix for
area calculations) and then enter the area value in the meter's SETUP mode in in
After the area value has been entered, use the L/mode button to scroll to the air volume
display (CMM/CFM) on the lower digits. Place the meter in air stream to measure volume.
8. Optional: measure Air Volume with an airflow Cone or Square adaptor by first attaching one
of the adaptors to the meter (the optional cone adaptor kit includes a round and a square
cone; kit part number AN300‐C). The meter will automatically recognize that the adaptor is
attached to the meter and a cone icon will appear on the display.
Note: regardless of the AREA setting in the SETUP mode, the meter will default to the
dimensions of the vane opening. Ensure that the airflow adaptor is well mounted and locked
before taking measurements.
LCD backlight
Press the U/mode button to switch ON the LCD backlight. The backlight will automatically switch
OFF after approximately 10 seconds to conserve battery power. Note that the backlighting
switches ON automatically when the meter is switched ON by the user.
button momentarily. Press the POWER
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