Extech Instruments SDL350 User manual

Hot Wire
5
USER MANUAL
Hot Wire Thermo-Anemometer with
Datalogger
Model SDL350

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Introduction
Congratulations on your purchase of the Extech SDL350 Hot Wire Thermo-Anemometer Datalogger.
This meter displays and stores air velocity and temperature readings. Temperature readings from the
thermometer built into the probe or from an externally connected type K or J thermocouple
temperature probe can be displayed and recorded. Data is stored on an SD card for transfer to a PC.
This instrument is shipped fully tested and calibrated and, with proper use, will provide years of reliable
service. Please visit the Extech Instruments website (www.extech.com) to check for the latest version
of this User Guide. Extech Instruments is an ISO-9001 certified company.
Safety
International Safety Symbols
This symbol, adjacent to another symbol or terminal, indicates the user must refer to the
manual for further information.
Description
METER AND HOT WIRE PROBE
1. Thermocouple input
2. Hot Wire input plug
3. Display for air velocity and air flow readings
4. Units of measure
5. HOLD / Backlight key
6. MAX-MIN key
7. SET and Clock key
8. PC interface jack
9. Reset key
10. Power Adaptor jack
11. SD card slot
12. ENTER and LOG key
13. Down ▼arrow and FUNCTION key
14. Up ▲arrow and UNIT key
15. Power ON-OFF key
16. Temperature reading with units of measure
17. Hot Wire probe cable
18. Telescoping probe handle
19. Protective cover (sensors underneath)
20. Colored dot must face air flow
HOT WIRE PROBE TOP (detail)
1. Air stream must face into colored dot
2. Air velocity sensor
3. Sliding protective cover OPEN position
4. Sliding protective cover CLOSED position
5. Temperature sensor
NOTES:
Battery compartment, tilt stand, and tripod mount are located on the rear of the instrument.
Items 8, 9, and 10 are located behind the snap-off compartment cover on right side of meter.

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Operation
Power ON-OFF
Power the meter ON or OFF by pressing and holding the power key for at least 1.5 seconds.
Meter Functions
This meter has three modes of operation: Air velocity (with temperature), thermocouple
temperature, and Air Volume (CFM/CMM). Press and hold the FUNCTION key for at least 1.5
seconds to switch from one mode to the other.
Air Velocity plus Temperature mode; meter displays An icon.
Type K or J thermocouple temperature mode (meter displays tP icon).
Air Flow (Volume CFM/CMM) meter displays F-US or F-EU depending how the meter is set up
for units of measure for area; refer to the SETUP mode for details.
Air Velocity plus Temperature Mode
1. Select the Air Velocity and Temperature mode as described above.
2. Connect the vane probe to the meter’s probe jack (top right of meter) via the probe plug.
3. Hold the probe by its handle and allow the air flow to enter the sensor area. Note that the air
flow must face the probe’s colored dot.
4. The meter will display the air velocity measurement (upper display area) and the air
temperature (lower display area).
Changing the Air Velocity Unit of Measure
This meter offers five (5) units of measure selections for air velocity: m/s (meters per second), FPM
(feet per minute), Km/h (kilometers per hour), knots, and mph (miles per hour).
1. Press and hold the UNIT key for at least 1.5 seconds to switch from one unit of measure to
another.
2. Note that pressing and holding the UNIT key continuously allows for quicker scrolling. Release
the key when the desired unit of measure is displayed.
Thermcouple (Type J or K) Temperature Mode
1. Select the Thermocouple Temperature mode using the FUNCTION button as described above.
2. The meter will display a ‘J’ or a ‘K’; on the left side of the display indicating the selected type.
To change the thermocouple type, refer to the Setup Mode section.
3. Connect a Type J or Type K thermocouple to the meter’s sub-miniature thermocouple jack (top
of meter on the left).
4. Hold the thermocouple in the air in the area to be tested.
5. The meter will display the thermocouple temperature in the main display area.
6. To change the temperature unit of measure (°C and °F) refer to the Setup Mode section.

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Air Flow (Volume CFM/CMM)
1. First measure and note the area of the duct or other passageway under test in square feet or
square meters. For rectangular ducts, area is calculated using Length * Width; for circular
ducts use 3.14 * R2.
2. Enter the area value in the SETUP mode (refer to SETUP mode section for details).
3. Select the Air Volume mode on the meter as described earlier using the FUNCTION key.
4. Connect the hot wire probe to the meter’s probe jack (top right of meter) and slide open the
probe’s protective cover to expose the hot wire sensor. Close the protective cover when the
probe is not in use.
5. Hold the probe by its handle and allow the air flow to pass through the sensor area. Note that
the air flow must face the probe’s colored dot. Refer to the meter and probe diagram section.
6. The meter will display the air volume measurement in the upper display area and the selected
unit of measure (US or EU) in the lower display area (F-US for CFM; F-EU for CMM). CFM
represents cubic feet per minute and CMM represents cubic meters per minute.
Data Hold
To freeze a measurement on the display, press the HOLD key momentarily. The meter will emit a
beep, the reading will hold, and the HOLD display icon will switch on. Press the HOLD key again to
release the display and exit the Data Hold mode returning the meter to the normal operating mode.
MAX-MIN Readings
For a given measurement session, this meter can record the highest (MAX) and the lowest (MIN)
readings for later recall.
1. Press the MAX-MIN key momentarily to access this mode of operation (REC icon appears)
2. The meter is now recording the MAX and MIN readings.
3. Press the MAX-MIN key again to view the current MAX reading (MAX icon appears). The
reading on the display is now the highest reading encountered since the REC icon was
switched on (when the MAX-MIN key was first pressed).
4. Press the MAX-MIN key again to view the current MIN reading (MIN icon appears). The
reading on the display is now the lowest reading encountered since the REC icon was
switched on (when the MAX-MIN key was first pressed).
5. To exit the MAX-MIN mode, press and hold the MAX-MIN key for at least 1.5 seconds. The
meter will beep, the REC-MAX-MIN icons will switch off, the memory will clear, and the meter
will return to the normal operating mode.
Display Backlight
To turn the display backlight ON or OFF, press and hold the backlight key for at least 1.5
seconds. The meter will beep when switching the backlight ON or OFF unless the beeper is
disabled as described in the Setup Mode section of this user guide.

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System Reset
If the meter’s keys become inoperable or if the display freezes, the Reset button can be used to
reset the instrument.
1. Use a paper clip or similar item to momentarily press the reset button located on the lower right
side of the instrument under the snap-off compartment cover.
2. After pressing the Reset button, switch the instrument ON by pressing and holding the
POWER key for at least 1.5 seconds. If using the power adaptor unplug the adaptor and then
plug it in again to power the meter.
AC Power Adaptor
This meter is normally powered by six (6) 1.5V ‘AA’ batteries. However, an optional AC 9V power
adaptor is available. To use the adaptor, insert the power adaptor plug into the jack on the bottom
right side of the meter (under the snap-off compartment cover); plug the other end of the adaptor
into an AC power source. The meter will now be permanently powered (as long as the adaptor is
used) and the power key will be disabled.
Datalogger
Types of Data Recording
Manual Datalogging: Manually log up to 99 readings onto an SD card via push-key press.
Automatic Datalogging: Automatically log data onto an SD memory card where the number of
data points is limited only by the card size. Readings are logged at a rate specified by the user.
SD Card Information
Insert an SD card (from 1G size up to 16G) into the SD card slot at the bottom of the meter.
With regard to orientation, the card should be inserted with the front of the card (label side)
facing toward the rear of the meter.
If the SD card is being used for the first time it is recommended that the card be formatted and
the logger’s clock set to allow for accurate date/time stamping during datalogging sessions.
Refer to the Setup Mode section for SD card formatting and time/date setting instructions.
European and USA numerical formats differ. The data on the SD card can be formatted for
either format. The meter defaults to USA mode where a decimal point is used to separate units
from tenths, i.e. 20.00. The European format uses a comma, i.e. 20,00. To change this setting,
refer to the Setup Mode section.
Manual Datalogging
In the manual mode the user presses the LOG key to manually log a reading onto the SD card.
1. Set the sampling rate to ‘0’ seconds.
2. Press and hold the LOG key for at least 1.5 seconds; the lower portion of the display will show
p-n(n= memory position number 1-99).
3. Press the LOG key momentarily to log a reading into memory. The REC icon will flash each
time a data point is stored (the SCAN SD icon will appear when the meter accesses the card).
4. Use the ▲and ▼keys to select one of the 99 data memory positions in which to record.
5. To exit the manual datalogging mode, press and hold the LOG key for at least 1.5 seconds.

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Automatic Datalogging
In automatic datalogging mode the meter takes and stores a reading at a user-specified sampling
rate onto SD card. The meter defaults to a sampling rate of one second. To change the sampling
rate, refer to the Setup Mode section (the sampling rate cannot be ‘0’ for automatic datalogging):
1. To begin an automatic Datalog session press and hold the LOG key for at least 1.5 seconds.
2. The meter will scan for an SD card and verify that it can be used to store data. If a card is not
inserted or if the card is defective, the meter will display SCAN SD indefinitely. In this case,
switch the meter OFF and try again with a valid SD card.
3. If the SD card is valid, the display will show the LOG icon (or the LOG icon alternating with the
temperature display) and then the REC icon will flash each time that a reading is stored.
4. To pause the datalogger, press the LOG key momentarily. The REC icon will stop flashing. To
resume logging simply press the LOG key again momentarily.
5. To terminate the datalogging session press and hold the LOG key for at least 1.5 seconds.
6. When an SD card is used for the first time a folder is created on the card and named AHB01.
Up to 99 spreadsheet documents (each with 30,000 readings) can be stored in this folder.
7. When datalogging begins a new spreadsheet document named AHB01001.xls is created on
the SD card in the AHB01 folder. The data recorded will be placed in the AHB01001.xls
document until 30,000 readings are reached.
8. If the measurement session exceeds 30,000 readings, a new document will be created
(AHB01002.xls) where another 30,000 readings can be stored. This method continues for up to
99 documents, after which another folder is created (AHB02) where another 99 spreadsheet
documents can be stored. This process continues in this same fashion with folders AHB03
through AHB10 (last allowable folder).
SD Data Card to PC Data Transfer
1. Complete a datalogging session as covered above. For the first test, simply record a small
amount of test data in order to gain some confidence and experience with the procedure.
2. With the meter switched OFF, remove the SD Card.
3. Plug the SD Card directly into a PC SD card reader. If the PC does not have an SD card slot,
use an SD card adaptor (available at most outlets where computer accessories are sold).
4. Power the PC and run a spreadsheet software program. Open the saved documents in the
spreadsheet software program (see example of a spreadsheet display below).
Spreadsheet data example

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RS-232/USB PC Interface
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/sdl350) are required.
Setup Mode
Basic settings at a glance
To view the current configuration of the meter with regard to time, date, thermocouple type and
datalogging sampling rate, press the SET/CLOCK ICON key momentarily. The meter will now
display the configuration in quick succession. Repeat as necessary to observe all of the information.
Accessing the Setup mode
1. Press and hold the SET key for at least 1.5 seconds to access the Setup menu.
2. Press the SET key momentarily to step through the available parameters. The parameter type
is shown on the bottom of the LCD and the current selection for that type is shown above it.
3. When a parameter is displayed that is to be changed, use the arrow keys to change the
setting. Press the ENTER key to confirm a change.
4. Press and hold the SET key for at least 1.5 seconds to exit the Setup mode. Note that the
meter automatically switches out of the Setup mode if no key is pressed in 7 seconds while in
the Setup mode.
5. The available Setup parameters are listed below. Additional detailed information is provided
below this list:
dAtE Set the clock time (Year/Month/Date; Hour/Minute/Second)
SP-t Set the datalogger sampling rate (1 – 3600 Second)
PoFF Automatic power-off management
bEEP Set beeper sound ON/OFF
dEC Set SD card Decimal character (comma for European format)
Sd F SD memory card Format
t-CF Select the Temperature unit of measure to C or F
tYPE Select the thermocouple type to K or J
F-US/F-EU Select F-US for CFM (cubic feet per minute) or F-EU for CMM (cubic meters
per minute) regarding Air Flow (Volume) measurements.
ArEA For CFM/CMM Air Flow (Volume) measurements the user enters the area of
the duct or other air passageway in units of square feet or square meters.
Setting the Clock Time
1. Access the dAtE parameter.
2. Use the arrow keys to change a value.
3. Use the ENTER button to step through the selections.
4. Press and hold the SET button for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
5. The clock will keep accurate time even when the meter is switched off. However, if the battery
expires the clock will have to be reset after fresh batteries are installed.

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Setting the Datalogger Sampling Time (Rate)
1. Access the SP-t parameter.
2. Use the arrow keys to select the desired sampling rate. The available settings are:
0, 1, 2, 5, 10,
30, 60, 120, 300, 600, 1800, and 3600 seconds.
3.
Press the ENTER key to confirm the entry.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Enabling/Disabling the Auto Power OFF Feature
1. Access the PoFF parameter.
2. Use the arrow keys to select ON (enable) or OFF (disable). With the Auto Power OFF feature
enabled, the meter will automatically switch OFF after 10 minutes of inactivity.
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Set the Beeper Sound ON or OFF
1. Access the bEEP parameter.
2. Use the arrow keys to select ON (enable) or OFF (disable).
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Numerical Setting (comma or decimal)
European and USA numerical formats differ. The meter defaults to USA mode where a decimal
point is used to separate units from tenths, i.e. 20.00; European formats use a comma, i.e. 20,00 to
separate units from tenths. To change this setting:
1. Access the dEC parameter as described in the Accessing Setup Mode section above.
2. Use the arrow keys to select USA or EUro.
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
SD Card FORMATTING
1. Access the Sd F parameter.
2. Use the arrow keys to select YES to format the card (select NO to abort). Note that all data on
the card will be lost if formatting is attempted.
3. Press ENTER to confirm selection.
4. Press ENTER again to re-confirm.
5. The meter will automatically return to the normal operating mode when formatting is complete.
If not, press and hold the SET key for at least 1.5 seconds to exit to the normal operation
mode.

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Set the Temperature Units of Measure (°C or °F)
1. Access the t-CF parameter.
2. Use the arrow keys to select °C or °F.
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Set the Temperature Thermocouple Type (J or K)
1. Access the tYPE parameter.
2. Use the arrow keys to select J or K.
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Set the Air Flow Volume measurement units to CFM (F-US) or CMM (F-EU)
1. Access the SET F-US / F-EU parameter.
2. Use the arrow keys to select US or EU. US represents CFM (cubic feet per minute) and EU
represents CMM (cubic meters per minute)
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Set the Area value for the air duct under test (for Air Flow Volume measurements only)
1. Access the ArEA parameter.
2. Use the arrow keys set the area of the duct (the equation L * W is used for rectangular ducts;
3.14 * R2is used for circular ducts). Note that the value must be set in square feet or square
meters; therefore if the measurement is made in square inches, the area value must be
converted to square feet. The setting range is 0.01 to 322.93.
3. Press ENTER to confirm setting.
4. Press and hold the SET key for at least 1.5 seconds to exit to the normal operation mode (or
simply wait 7 seconds for the meter to automatically switch to the normal operating mode).
Battery Replacement and Disposal
When the low battery icon appears on the LCD, the batteries must be replaced. Several hours
of accurate readings are still possible in this condition; however batteries should be replaced as
soon as possible:
1. Remove the two (2) Phillips screws from the rear of the meter (directly above the top of the tilt
stand).
2. Remove and safely place the battery compartment and screws where they will not be damaged
or lost.
3. Replace the six (6) 1.5V ‘AA’ batteries observing polarity.
4. Replace the battery compartment cover with the two (2) Phillips screws.
All EU users are legally bound by the Battery Ordinance to return all used batteries to
community collection points or wherever batteries / accumulators are sold!
Disposal in household trash or refuse is prohibited!
Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the
end of its lifecycle
Other Battery Safety Reminders
Never dispose of batteries in a fire. Batteries may explode or leak.
Never mix battery types. Always install new batteries of the same type.

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Specifications
General Specifications
Display Backlit LCD; LCD size: 52 x 38mm (2 x 1.5”)
Sensor types Hot-wire thermistor for air velocity and air flow measurements
Thermistor for temperature sensor built into hot wire probe
Thermocouple for remote temperature measurements
Measurement Units Air velocity: m/S (meters per second) Km/h (kilometers per hour)
Ft/min (FPM; feet per minute), Knots (nautical miles per hour), Mile/h
(mph; miles per hour)
Air temperature: ° C / ° F
Air Flow (Volume): CFM or CMM
Type K / Type J thermocouple: ° C / ° F
Datalogger Sampling Rate AUTO: 1, 2, 5, 10, 30, 60, 120, 300, 600, 1800, 3600
seconds. Note that a one (1) second sampling rate can
cause some data loss on slower computers.
MANUALLY: Set the sampling rate to ‘0’
Memory Card SD memory card; 1G to 16GB size
Temperature Compensation Automatic temperature compensation for the Anemometer
function and the type K/J thermometer function
Data Hold Freeze the display reading
Memory Recall Record and Recall the Maximum and Minimum readings
Display update rate Approx. 1 second
Data Output RS-232 / USB PC computer interface
Operating Temperature 0 to 50°C (32 to 122°F)
Operating Humidity 85% R.H. max.
Auto Power OFF After 10 minutes of inactivity (can be disabled)
Power Supply Six (6) 1.5VDC batteries (optional 9V AC adaptor)
Power Consumption Normal operation (backlight & datalogger OFF): Approx. 30 mA dc
With backlight OFF and datalogging ON: Approx. 50 mA dc
Weight 347g (0.76 lbs.); meter only
Dimensions Main instrument: 182 x 73 x 47.5mm (7.1 x 2.9 x 1.9”)
Telescoping probe: 12mm (0.5”) diameter x 280mm (11”) min.
length; 12mm (0.5”) diameter x 940mm (37”) max. length
Cable length: 2.1m (7’)