4 SDL550-EU-EN V1.4 3/14
Selecting Meter Functions
The SDL550 can measure Humidity Content (%RH), Dew Point Temperature (
°
C/
°
F), Wet Bulb
Temperature (
°
C/
°
F), and Thermocouple Temperature (
°
C/
°
F). Press and hold the FUNCTION button
for 1.5 seconds to begin scrolling through the functions. Release the FUNCTION button when the
desired function is displayed. Refer to the table below.
Functions Primary display Secondary display Unit of measure
Humidity Content Relative Humidity rh briefly displayed then the
Humidity Content Probe Temp.
RH% and
o
C or
o
F
Dew Point Temperature* dp display icon
°
C or
°
F
Wet Bulb Temperature* _et display icon
°
C or
°
F
Air Temperature Thermocouple Temperature tp briefly displayed
°
C or
°
F
Measurements
Moisture Content Measurements
1. Connect the Humidity Content probe to the jack at the top of the meter on the right
2. Switch the meter ON by pressing and holding the power button for 1.5 seconds
3. Press and hold the FUNCTION button to select the Humidity Content mode. When the Humidity
Content mode is selected, the display icon rh is briefly shown
4. Carefully remove the protective cap from the Humidity Content probe. The probe tip is extremely
sharp, use caution
5. Insert the probe tip into the material under test far enough to cover the sensor’s openings
6. The meter will now display Humidity content in %RH on the primary (upper) LCD digits
7. The secondary (lower) LCD digits will show the temperature measured by the Humidity content
probe’s built-in temperature sensor. Use the Setup mode to change the temperature units of
measure
8. Note that the probe uses a built-in filter. When the filter needs replacing (becomes soiled or
defective), the measurement readings require a longer stabilization time. Please contact Extech
for replacement filters
Dew Point and Wet Bulb Temperature Measurements
1. Connect the Humidity Content probe to the jack at the top of the meter on the right
2. Switch the meter ON by pressing and holding the power button for 1.5 seconds
3. Press and hold the FUNCTION button to select the Wet Bulb or the Dew Point mode. When the
Dew Point mode is selected, the display icon dp is shown on the secondary display area. When
the Wet Bulb mode is selected, the display icon _et is shown on the secondary display area.
4. Carefully remove the protective cap from the Humidity probe. The probe tip is extremely sharp,
use caution
5. Insert the probe tip into the material under test far enough to cover the sensor’s openings
6. The meter will now display the Dew Point Temperature or Wet Bulb Temperature on the primary
(upper) LCD digits. Use the Setup mode to change the temperature units of measure
