Operation; Lcd Backlight - Extech Instruments AN320 User Manual

Operation
Air Velocity and Air Volume Measurements
1. Switch the meter ON by pressing the POWER
countdown from 30 to 0 as it performs a self‐test. Press 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, relative humidity, or CO
button to scroll). 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, Relative humidity, and CO
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 DP, or wet bulb
WBT) are indicated in °C/°F. 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. Optionally, measure Air Volume with an airflow cone 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 the adaptor and the 'INSERT
Cone Shape' prompt will appear on the LCD (the adaptor icon will also appear). Select round
or square using the meter's keypad. Note that, regardless of the AREA setting in the SETUP
mode, the meter will default to the dimensions of the attachment (Square: 356 x 346mm
[13.6 x 13.6"); Round: 210mm [8.3"] diameter). NOTE: 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.
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button momentarily. The meter will
(use the U/mode
2
sensors are located at the center of the vane on
2
6
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2 2
or cm .
AN320-EU-EN V1.0 1/13