Extech Instruments 407119-NIST User manual

User Manual
Heavy Duty Hot Wire CFM Thermo-Anemometer
Model 407119

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Introduction
Congratulations on your purchase of the Extech 407119 Thermo-Anemometer. The 407119
measures air velocity, air volume, and air temperature. It uses a telescoping probe antenna to
allow convenient access to grills and diffusers. Careful use of this meter will provide years of
reliable service. The Model 407119 features are listed below.
Features
Combination hot wire probe (for air velocity) and thermistor sensor (for temperature) deliver
rapid and precise measurements even at low air velocity values.
Slim probe design with telescoping antenna for easy grill and diffuser access
Air Velocity, Air Volume, and Air Temperature measurements
20 Reading Average feature
Zero adjustment
Data Hold and Record/Recall Max/Min features
Auto Power OFF
PC Interface (RS-232) with optional software and cable for data acquisition
Applications
Environmental testing, air conveyors, flow hoods, clean rooms, air balancing,
fans/motors/blowers, furnace velocity, paint spray booths, and others.

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Specifications
General Specifications
Display
Dual function 5-digit LCD
Measurement units
Air Velocity: m/s, km/h, ft/min, knots, mph;
Air Flow: CMM (m3/min) and CFM (ft3/min);Temperature: °C and °F
Data hold
Freezes displayed reading
Sampling rate
Display update rate:1 second (approx.)
Sensors
Air velocity and temperature sensors: Thermistor type
MAX/MIN Memory
Record and view Maximum and Minimum readings
Average feature
Averages up to 20 readings
Automatic Power off
Auto shut off after 15 minutes
Data Output
RS-232 PC serial interface with 16-bit data stream output
Operating Temp.
0 to 50°C (32 to 122°F)
Operating Humidity
Max. 80% Relative Humidity
Power Supply
Four (4) ‘AA’1.5V batteries or optional AC adaptor
Power Current
70mA DC (approx.)
Weight (meter only)
521g (1.15 lbs.) with batteries installed
Dimensions
Main instrument: 200.0 x 76.2 x 36.8mm (7.9 x 3.0 x 1.5")
Telescoping Sensor: 12.7mm (0.5") diameter head
Min length of sensor: 260mm (8”); Max. length: 0.94m (37”) with 1.7m
(5.5’) cable
Range Specifications
Air Velocity
Range
Resolution
Accuracy (of rdg)
m/s (meters per second)
0.2 –17.0 m/s
0.1
±(5%rdg + 0.5 m/s)
km/h (kilometers per hour)
0.7 –61.2 km/h
0.1
±(5%rdg + 1.8 km/h)
ft/min (feet per minute)
40 –3346 ft/min
1
±(5%rdg + 98 ft/min)
mph (miles per hour)
0.5 –38.0 mph
0.1
±(5%rdg + 1.1 mph)
knots (nautical miles per hour)
0.4 to 33.0 knots
0.1
±(5%rdg + 1.0 knots)
Air Flow Measurements
Range
Resolution
Area Range
CMM (cubic meters per min.)
0 –36,000 m3/min
0.001 to 1
0.001 to 30.0 m2
CFM (cubic feet per minute)
0 –1,271,200 ft3/min
0.01 to 100
0.01 to 322.91ft2
Air Temperature
Range
Resolution
Accuracy
0 to 50oC
(32 to 122oF)
0.1oC/F
±2.0oC (3.6oF)

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Meter Description
1. Display
2. POWER button
3. HOLD and ESC button
4. REC and ENTER button
5. UNIT, ZERO, and ▲up arrow button
6. Function and ▼down arrow button
7. AVG. and ►right arrow button
8. AREA SETUP button
9. Tilt stand
10. Battery compartment / Cover
11. Tripod mount
12. LCD contrast adjustment pot
13. System reset switch
14. RS-232 Output terminal
15. DC9V power adaptor

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Operation
Initialization and Zero procedures (please follow these steps before use)
Important Note: The meter’s probe locking switch must be in the
locked position (with the probe inserted) for the meter to turn on
and operate correctly. Refer to the accompanying diagram or the
diagram at the top of the meter for switch orientation.
For the best accuracy and for proper operation, the following
steps must be performed.
1. Connect the sensor to the input jack on top of the meter by
first unlocking the sensor jack and then inserting the sensor
plug. Lock the sensor jack after the probe is inserted.
2. Press the POWER button to turn on the meter. The meter will
perform a self-test during which the display will count down
from 9999 to 0000.
3. Select the air velocity function using the FUNCTION button. The LCD will display the most
recently selected unit of measure for air velocity.
4. To change the temperature units of measure (C/F), use the advanced programming mode
discussed later in this manual.
5. Momentary presses of the UNIT button changes the air velocity units. The LCD will reflect the
selection.
6. Place the sensor cover in the up (ZERO) position (see diagram below).
7. Open the telescoping sensing antenna to a convenient length.
8. Place the sensor in the area to be measured and allow a short time for it to stabilize to the
ambient temperature.
9. To Zero the meter display, press and hold the ZERO button until the second beep.
Warning! Do not touch the air velocity or temperature thermistors inside the sensor head while
moving the sensor cover.

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Air Velocity Measurements
1. Follow the Initialization and Zeroing procedures above before continuing.
2. Open the antenna to the desired length.
3. Slide the air velocity sensor cover down.
4. Press the POWER button to turn the meter on.
5. Place the sensor in the air
current to be measured.
Have the air flow meet the
sensor head in the
direction of the white dot
(as shown in diagram).
6. View the air velocity and temperature readings on the LCD Display. The large main LCD display
shows the Air Velocity reading. The lower LCD sub-display shows the temperature reading (left)
and the unit of measure (right).
7. To turn the meter off, press and hold the POWER button until the meter switches off.
Air Flow (Volume) Measurements (CMM / CFM)
NOTE: Temperature is not displayed while the meter is in the Air Flow mode.
1. Follow the steps in the Initialization and Zeroing section before continuing.
2. Select the air flow mode using the Function button. The LCD will display CMM (cubic meters per
minute) or CFM (cubic feet per minute) when Air Flow is selected.
3. Press the UNIT button momentarily to select the desired air flow units: CMM or CFM. The LCD
display will reflect the selection.
4. Calculate the area of the duct or vent under test (refer to the Useful Conversions and Equations
section in the back of this manual for assistance). Be sure to compute the area of the vent or
duct in square feet or meters. If you have the area in inches, convert inches to feet before
programming the meter with the area value.
5. Press the AREA SET button to begin entering the area in m2or ft2. The left digit will begin
flashing. Follow the steps below to enter the area of the duct or vent in question:
Use the ►button to select a digit to change (digit will flash)
Use the ▲button increase the value of the flashing digit
Use the ▼button to decrease the value of the flashing digit
6. Press the REC/Enter button and then the AREA SET button to save the new area value
7. After the area has been entered, the new area value will be shown on the lower left of the LCD
display in ft2or m2. If the unit of measure is CFM, the area will be shown in square feet. If the
unit of measure is CMM, the area will be shown in meters squared.
8. Press the ESC button to abort the programming at any time.
9. Place the probe in the area under test. The main LCD digits will indicate the air flow in CFM or
CMM. If the CFM or CMM reading exceeds 99999, use the displayed X10 multiplier to calculate
the reading.
10. To turn the meter off, press and hold the POWER button until the meter switches off.

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AVERAGE Feature for the Air Flow Mode
In the Average mode, up to 20 readings can be stored and averaged.
1. In the Air Flow Mode (discussed earlier), press the FUNCTION button momentarily until the
AVG icon and a ‘zero’ appears on the lower LCD display line.
2. Press the AVG START button to record the current reading. A ‘1’ will appear on the lower LCD
line indicating that one reading has been stored.
3. Press the AVG START for up to a total of 20 measurements. The number on the lower LCD line
will increment with each press of the AVG START button letting the user know how many
readings are currently being averaged. Note that only the averaged reading is shown while in
this mode, not the actual reading.
4. To clear (erase) all of the currently stored readings and start again, press and hold the AVG
button until the meter beeps twice. Note that the counter resets to ‘0’ and that the meter is ready
to start another averaging session.
5. Use the FUNCTION button to exit this mode of operation.
Data Hold Feature
1. While taking measurements, press the HOLD button to freeze a reading.
2. The HOLD indicator will appear on the LCD when the display is in Data Hold mode.
3. Press HOLD again to return to normal operation.
Maximum (MAX) and Minimum (MIN) Recording
The MAX / MIN Record-Recall feature allows the user to record and view the highest and lowest
readings during a measurement session.
1. Press the REC button once. The REC indicator will appear on the display and the meter will
begin keeping track of the MAX and MIN values.
2. To view the MAX reading, press REC again. The MAX indicator along with the maximum
reading will appear on the LCD display.
3. Press REC again to view the minimum value, the MIN indicator along with the minimum reading
will appear on the LCD display.
4. To return to normal operation, press and hold the REC button for approx. 3 seconds (until the
meter beeps). The display indicators REC, MAX, and MIN will disappear.
Note: Auto Power Off is disabled in the RECORD mode.
Auto Power Off
To save battery life, the meter will automatically shut off after approximately 15 minutes of
operation. To temporarily disable this feature (until the meter’s power is cycled), press the REC
button and enter the RECORD mode. Alternatively, go to the advanced programming section (later
in this manual) for instructions on how to disable it long term.

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Advance Programming Mode
From the Air Velocity mode of operation, press and hold the SET button until the meter beeps and a
‘1’ is displayed. The advanced programming mode is now accessed. The Auto Power OFF
Enable/Disable and the Temperature Units selections are available in the advanced programming
mode. Use the ESC button to exit this mode at any time.
Auto Power Enable/Disable
The first parameter in the advanced mode is the Auto Power OFF enable/disable. Use the up and
down arrow keys to select the desired value. ‘0’ defeats the Auto Power OFF feature; ‘1’ enables the
Auto Power OFF feature. Momentarily press the SET button to move to the next parameter
temperature units (see below).
Temperature Units selection (C/F)
The second parameter in the advanced mode is the Temperature Units selection. Use the up and
down arrow keys to select the desired value. ‘0’ selects degrees ‘C’; ‘1’ selects degrees ‘F’. Press
the Rec/Enter button to confirm temperature selection. Press the ESC button to exit the advanced
programming mode.
System Reset
If the meter’s display ‘locks up’ and/or the button presses do not cause the display to change, try a
system reset. To reset the meter, use one of the following methods.
1. Move the probe lock switch from the ON to the OFF to the ON position again. Turn the meter on.
2. While powering the meter, press the RESET switch (side compartment) using the point of a
paper clip.
PC Interface
The 407119 is equipped with a 3.5mm jack (side compartment) for connection to a PC for data
acquisition purposes. The meter’s data output is a 16 bit data stream. For streaming of data to a PC
via the RS232 Output jack, the optional 407001-USB kit (RS232 to USB cable and driver CD) along
with the 407001 software (available free at www.extech.com) are required.
Battery Replacement
When the battery icon appears on the lower left corner of the LCD display, the four (4) ‘AA’ batteries
must be replaced.
1. Remove the rear Phillips head screw
2. Slide off the rear battery compartment
3. Replace the batteries
4. Secure the battery compartment
Never dispose of used batteries or rechargeable batteries in household waste.
As consumers, users are legally required to take used batteries to appropriate
collection sites, the retail store where the batteries were purchased, or wherever
batteries are sold.

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Useful Equations and Conversions
Area equation for rectangular or square ducts
Area equation for circular ducts
Cubic equations
NOTE: Measurements made in inches
must be converted to feet or meters before using the above formulae.
Unit of Measure Conversion Table
m/s
ft/min
knots
km/h
MPH
1 m/s
1
196.87
1.944
3.6
2.24
1 ft/min
0.00508
1
0.00987
0.01829
0.01138
1 knot
0.5144
101.27
1
1.8519
1.1523
1 km/h
0.2778
54.69
0.54
1
0.6222
1 MPH
0.4464
87.89
0.8679
1.6071
1
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Width (W)
Height (H)
Area (A) = Width (W) x Height (H)
CFM (ft3/min) = Air Velocity (ft/min) x Area (ft2)
CMM (m3/min) = Air Velocity (m/sec) x Area (m2) x 60
Radius
Area (A) = pi x r2
Where pi= 3.14 and r2= radius x radius