Extech Instruments 407412 User manual

User's Manual
Hygro Thermo-Anemometer
Model 407412

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Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in
parts and workmanship for one year from date of shipment (a six month limited warranty
applies to sensors and cables). If it should become necessary to return the instrument for
service during or beyond the warranty period, contact the Customer Service Department at
[phone] ext. 210 for authorization or visit our website www.extech.com for contact
information. A Return Authorization (RA) number must be issued before any product is
returned to Extech. The sender is responsible for shipping charges, freight, insurance and
proper packaging to prevent damage in transit. This warranty does not apply to defects
resulting from action of the user such as misuse, improper wiring, operation outside of
specification, improper maintenance or repair, or unauthorized modification. Extech
specifically disclaims any implied warranties or merchantability or fitness for a specific
purpose and will not be liable for any direct, indirect, incidental or consequential damages.
Extech's total liability is limited to repair or replacement of the product. The warranty set
forth above is inclusive and no other warranty, whether written or oral, is expressed or
implied.
Introduction
Congratulations on your purchase of Extech's Hygro Thermo-Anemometer. This Heavy
Duty meter measures and displays Air Velocity + Temperature and Relative Humidity +
Temperature. Air flow can be displayed in the following units of measure: feet per minute,
meters per second, miles per hour, kilometers per hour, and knots. Temperature and RH
units are displayed in oC/oF and % units respectively. This meter is shipped fully tested and
calibrated and, with proper use, will provide years of reliable service.
Specifications
General Specifications
Display Dual function, 4-digit (9999 count) LCD display
Units of measure m/s (meters per second), km/hr (kilometers per hour), ft/min (feet per
minute), knots (nautical miles per hour), mile/hr (miles per hour);
Temperature: °C/°F; Humidity: %RH
Data hold Holds reading on the LCD display when button is pressed
Sensors Air velocity sensor: Twisted vane arm with low friction ball bearing;
Temperature: Precision thermistor; Humidity: Thin film capacitor
Max/Min Record Records highest and lowest readings for later recall
Data Output RS-232 serial PC interface
Operating Temp. 32°F to 122°F (0°C to 50°C)
Operating Humidity Max. 80% RH
Power Supply 9V battery
Power Consumption Approx. 8.3 mA DC
Weight 0.77 lbs. (350g)
Dimensions Meter: 7.1x2.8x1.3" (180 x 72 x 32mm);
Anemometer Probe: 0.7" (17mm) Diameter x 6.7" (170mm)
Accessories Anemometer/temperature and RH Probes, 9V battery, & case

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Range Specifications
Air velocity
Measurement Range Resolution Accuracy (% of reading)
ft/min (feet/min) 80 - 4921 ft/min 1 ft/min ± (2% + 20 ft/min)
m/s (meters/sec) 0.4 - 25.00 m/s 0.01 m/s ± (2% + 0.2 m/sec)
km/h (kilometers/hour) 1.4 - 90.0 km/h 0.1 km/h ± (2% + 0.2 km/hr)
mph (miles/hour) 0.9 - 55.9 mph 0.1 mph ± (2% + 0.2 mph)
knots (nautical miles/hour ) 0.8 to 48.6 knots 0.1 knots ± (2% + 0.2 knots)
Temperature
Range Resolution Accuracy
32oF to 122oF (0oC to 50oC) 0.1oF/oC±1.5oF (±0.8oC)
Relative Humidity
Range Resolution Accuracy
10 to 70% RH 0.1% ±3% RH
70 to 95% RH 0.1% ±4% RH

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Meter Description
1. Sensor input plug – The Anemometer sensor and the Humidity sensor use the same
jack at the top of the meter.
2. RS-232 PC Interface jack
3. LCD Display
4. Keypad (see below)
POWER Press to turn the meter ON or OFF
HOLD Press to freeze the currently displayed reading
C/F Press to select the temperature unit of measure
RECORD Press to track the MAX and MIN readings
RECALL Press to retrieve the current MAX and MIN memory
FUNCTION Select Humidity (left position) or Air Velocity (right position)
UNIT Select the unit of measure for Air Velocity
5. Battery compartment and tilt sand are located on the back of the meter
6. Rubber protective jacket
7. Vane Anemometer sensor
8. Humidity sensor
1
2
3
4
5
6
7
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airflow
Yellow
Dot
Anemometer and Temperature Operation
1. Insert the Vane sensor into the meter's input jack at the top of the meter.
2. Press the POWER button to turn the instrument on.
3. Select Anemometer (Air Velocity) operation by placing the function slider switch to the
vane icon .
4. Select the temperature units by pressing the °C/°F button. The LCD display will
indicate '°C' or '°F' as selected.
5. Select the air velocity unit of measure by pressing the
UNIT button. With each press the display scrolls
through the units (m/s, km/hr, ft/min, knots, & mile/h).
6. For maximum accuracy, the yellow dot must be on the
exhaust side of the vane as shown.
7. The meter’s LCD will indicate Air Velocity +
Temperature.
Relative Humidity and Temperature Operation
1. Insert the Relative Humidity probe in the input jack at the top of the meter.
2. Press the POWER button to turn on the instrument.
3. Select the Humidity mode of operation by placing the function slider switch to the
RH% position.
4. Select the temperature units by pressing the °C/°F button. The LCD display will
indicate '°C' or '°F' as selected.
5. Hold the probe by the handle in the area to be monitored. The meter will display
Relative Humidity + Temperature.
6. Note that humidity measurements take several minutes to stabilize.
Data Hold
Press the DATA HOLD button to freeze the displayed reading. The DH icon will appear on
the LCD while Data Hold is engaged. Press the DATA HOLD button again to resume
normal operation.
Min/Max Record Mode
When selected, the Record mode stores the highest (Max) and lowest (Min) readings for
later recall. To use Record mode:
1. Press the RECORD button. The REC indicator will appear on the LCD display.
2. Start a measurement session.
3. After the measurement session, press the RECALL button to view the highest (Max)
reading recorded since the RECORD button was pressed. The MAX indicator will
appear to inform the user that the displayed reading is the highest value recorded.
4. Press the RECALL button again to view the lowest reading encountered since the
RECORD key was pressed (the MIN indicator will appear on the LCD to inform the
user that the reading displayed is the lowest value recorded).
5. Press RECORD again to return the meter to normal operation. All stored data will be
cleared and the REC/MIN/MAX icons will disappear from the LCD.
6. Note that putting the meter into the Record mode defeats the Auto Power Off feature.

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RS-232 PC Interface
The RS-232 serial data port (3.5mm phono jack) is located at the top of the meter next to
the sensor input jack. The PC interface hardware is intended for use with the Extech Data
Acquisition software package, Part Number 407001 which includes WindowsTM 95 / 98 /
ME / NT / 2000 compatible software and PC interface cable. For more information, contact
Extech or refer to the 407001 User's Manual.
Auto Power Off feature
The Auto Power Off feature automatically turns the meter off after approximately 10
minutes. To defeat this feature, place the meter in Record mode by pressing the RECORD
key once (the REC icon will appear on the LCD). The meter will remain powered as long
as the meter is in the RECORD mode.
Battery Replacement
When it is time to replace the 9V battery, the low battery indicator (LBT) appears in the left-
hand corner of the LCD display. Note that reliable readings can be obtained for several
hours after the first appearance of the low battery indicator.
To replace the battery:
1. Remove the meter's protective rubber holster.
2. Open the battery compartment on the back of the meter using a small coin or a flat
blade screwdriver.
3. Replace the 9V battery, close the compartment, and replace the holster.
Relative Humidity and Temperature Calibration
1. Turn the meter on and select the Humidity mode (RH %) using the Function switch.
2. Use a temperature simulator or calibrator to apply 0.0 ºC to the meter and adjust VR3
for a display of 0.0 ºC.
3. Change the input to 25.0 ºC and adjust VR1 for a display of 25.0 ºC.
4. Change the input to 50.0 ºC and verify a display of 50.0 ºC. Readjust VR3 & VR1 if
necessary.
5. Connect the humidity probe to the unit and place the probe in a controlled 33% RH
environment. Let stabilize for a minimum of 30 minutes and adjust VR5 for a reading of
33.0% RH.
6. Place the probe in a 75% RH environment for a minimum of 30 minutes and adjust “R6
for a reading of 75.0% RH.
7. Verify that the temperature reading is within the published specifications. If not, perform
calibration steps 2 and 3, above, again.

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
Support line [phone]
Technical support: Extension 200; E-mail: [email protected]
Repair & Returns: Extension 210; E-mail: [e-mail]
Product specifications subject to change without notice
For the latest version of this User Guide, Software updates, and other
Up-to-the-minute product information, visit our website: www.extech.com
Extech Instruments Corporation, 285 Bear Hill Road, Waltham, MA 02451
Calibration and Repair Services
Extech offers repair and calibration services for the products we sell. Extech also
provides NIST certification for most products. Call the Customer Service Department for
information on calibration services available for this product. Extech recommends that
annual calibrations be performed to verify meter performance and accuracy.
Copyright ©2006 Extech Instruments Corporation.
All rights reserved including the right of reproduction in whole or in part in any form.

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Appendix
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 1196.87 1.944 3.6 2.24
1 ft/min 0.00508 10.00987 0.01829 0.01138
1 knot 0.5144 101.27 11.8519 1.1523
1 km/h 0.2778 54.69 0.54 10.6222
1 MPH 0.4464 87.89 0.8679 1.6071 1
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) = x r2
Where  = 3.14 and r2= radius x radius