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User Manual
RHT52
Psychrometer + IR Thermometer
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Introduction
Congratulations on your purchase of the Triplett RHT52 Psychrometer + IR
Thermometer. This handheld meter measures and displays Air
Temperature, Relative Humidity, Dew Point, Wet Bulb and also Surface
Temperature using the built-in IR thermometer.
Safety
Use extreme caution when the laser pointer beam is on
Do not point the beam toward anyone's eye
or allow the beam to strike the eye from a
reflective surface
Do not use the laser near explosive
gases or in other potentially explosive
areas
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Description
METER DESCRIPTION
1. Humidity & Air
Temperature Sensor
2. Type K Thermocouple
input jack
3. Laser pointer beam
4. IR temperature sensor
5. USB Interface
6. LCD Display
7. Upper display HOLD
button
8. Upper display Temp./Wet
Bulb/Dew Point button
9. Upper display record
Max/Min button
10. IR Measurement button
11. °F/°C units button
12. Lower display HOLD
button
13. Lower display record Max/Min button
14. Backlight button
15. Power button
NOTE: Battery Compartment, Tilt Stand and Tripod Mount are located
on the reverse side of the meter
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LCD DISPLAY
1. Low Battery icon
2. PC communication icon
3. Upper display function icons
4. Upper display
5. Laser pointer icon
6. Lower display function icons
7. Lower display
8. Lower display function icons
Operation
Basic Measurements
3. Press the button to turn power on.
4. The upper display will indicate Air Temperature, Wet Bulb
5. The lower display will indicate Type K
6. Press the °C/°F button to change the temperature units from °C or °F.
Temperature or Dew Point Temperature and % Relative
Humidity.
Press the WB/DP button to toggle between Air, WB or DP.
temperature or IR Temperature. Press and
hold the IRT button to select the IR
Thermometer.
The TYPE-K function will display “-------“ if a type k probe is not inserted
into the meter.
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Non-contact IR Surface Temperature Measurements
The built-in IR sensor can remotely measure the
temperature of most surfaces. The Laser pointer allows
the user to aim accurately when taking non-contact
measurements.
1. Turn ON the meter using the button.
2. The IR sensor and laser pointer are located at the top of the meter.
3. Point the sensor toward the surface to be measured.
4. Press and hold the IRT button to begin measuring the surface
temperature of a
desired target. IR TEMP and will appear on the
display. The laser pointer will switch on to help aim the
meter.
5. The measured IR surface temperature will appear on the lower display.
6. When the IRT button is released, the laser pointer will
switch off and the reading will freeze (data hold) on
the display for approximately 7 seconds.
7. After the 7 second hold time the meter returns to the type k mode.
WARNING: Do not directly view or direct the laser pointer at an eye.
Low power visible lasers do not normally present a hazard, but may
present some potential for hazard if viewed directly for extended
periods of time.
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Data Hold
1. Press the HOLD buttons (one for upper display and one for lower
display) to freeze the displayed value for the respective display. Press
again to unlock the display.
2. The HOLD icon will appear on the display when the Data Hold mode is
active.
MIN-MAX Recording Mode
4. Press the MAX/MIN button (one for upper display and one for lower
display) to begin recording the Maximum and Minimum reading. The
REC MAX icon will appear and only the maximum value measured
will appear in the display. The display will update only if a value
higher than the currently displayed value is measured.
5. Press the MAX/MIN button again to display the minimum values. The
REC MIN icon will appear and only the minimum recorded value will
appear in the display.
6. Press the MAX/MIN button again to display the currently measured
values. The REC icon will appear in the display and the Max and
Min values will be stored in memory.
7. Press and Hold the MAX/MIN button for >2 seconds to exit the mode.
Backlight
Press the backlight button to turn the backlight ON or OFF.
Note: continuous use of the backlight function will reduce battery life.
Auto-Power Off
The meter will automatically turn off after 15 minutes of operation if no
buttons are pressed during this period. Auto-power off can be disabled
by:
1. Hold the IRT button and then press the button to turn the power
on. When “disAPO” appears in the display, release the IRT button
and the APO is disabled.
Low Battery
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When the battery reaches the minimum operating voltage the battery icon
will appear in the display.
Replace the 9V battery when this happens.
Battery Replacement
When the battery icon appears on the LCD, the 9V battery must be
replaced.
1. The battery compartment is located on the rear of the meter.
2. Press in and down on the arrow located above the tilt stand hinge.
3. Replace the 9V battery
4. Replace the battery cover.
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.
Disposal: Do not dispose of this instrument in household waste. The user
is obligated to take end-of-life devices to a designated collection point for
the disposal of electrical and electronic equipment.
Other Battery Safety Reminders
1. Never dispose of batteries in a fire.
Batteries may explode or leak. Never mix
battery types. Always install new batteries of
the same type
2.
USB Interface and Software
The RHT52 is equipped with a communication jack on its upper left
side. The supplied communications cable connects to this jack and to a
USB port on a PC. The supplied software allows the user to view and
save readings to the PC. Instructions for use and features are detailed
in the supplied software HELP utility.
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InfraRed Measurement Considerations
When taking IR measurements the meter automatically compensates for
ambient temperature changes. Note that it may take up to 30 minutes to
adjust to extremely wide ambient changes.
Low temperature measurements quickly followed by high
temperature measurements may require several minutes to
stabilize as a result of the IR sensor cooling process.
If the surface of the object under test is covered with frost, oil,
grime, etc., clean before taking measurements.
If an object's surface is highly reflective apply masking tape or flat
black paint before measuring. Steam, dust, smoke, etc. can obstruct
measurements.
To find a hot spot, aim the meter outside the area of interest then
scan across (in an up and down motion) until the hot spot is
located.
IR measurements cannot be made through glass.
IR Theory
IR thermometers measure the surface temperature of an object. The
meter’s optics sense emitted, reflected, & transmitted energy that is
collected and focused onto the meter’s detector. The meter’s circuitry
translates this information into an LCD reading.
IR Field of View
Ensure that the desired target is larger than the spot size. As the distance
from an object increases, the spot size of the area measured by the
meter becomes larger. The meter’s field of view ratio is 30:1, meaning
that if the meter is 30 inches (cm) from the target, the diameter (spot) of
the object under test must be at least 1 inch (cm). Refer below to the field
of view diagram.
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Material
Emissivity
Material
Emissivity
Asphalt
0.90 to 0.98
Cloth (black)
0.98
Concrete
0.94
Human skin
0.98
Cement
0.96
Leather
0.75 to 0.80
Sand
0.90
Charcoal
(powder)
0.96
Earth
0.92 to 0.96
Lacquer
0.80 to 0.95
Water
0.67
Lacquer (matt)
0.97
Ice
0.96 to 0.98
Rubber (black)
0.94
Snow
0.83
Plastic
0.85 to 0.95
Glass
0.85 to 1.00
Timber
0.90
Ceramic
0.90 to 0.94
Paper
0.70 to 0.94
Marble
0.94
Chromium oxides
0.81
Plaster
0.80 to 0.90
Copper Oxides
0.78
Mortar
0.89 to 0.91
Iron Oxides
0.78 to 0.82
Brick
0.93 to 0.96
Textiles
0.90
Emissivity
Most organic materials and painted or oxidized surfaces have an
emissivity of 0.95. Inaccurate readings will result when measuring shiny
or polished surfaces. To compensate, cover the surface under test with
masking tape or flat black paint. Allow time for the tape to reach the
same temperature as the material underneath then measure the
temperature of the tape or the painted surface.
Thermal Emissivity Table for Common Materials
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Specifications
General Specifications
Display Dual Display Multi-function LCD with 9999
counts
Data Hold Freezes displayed reading
Sampling rate 1 reading per second
Sensors Relative Humidity: Capacitance, Air Temp:
Thermistor
IR Distance to Spot ratio 30:1
IR Spectral response 6 to 14µm
IR Emissivity 0.95 fixed
MIN-MAX Record and Recall lowest and highest readings
Auto Power OFF Automatic shut off after 15 minutes (can be
disabled)
PC Interface USB PC Communication with supplied
software and cable for data
Over range indication Dashes appears on the LCD
Low battery indication Battery symbol appears on the LCD
Power supply 9V Battery
Operating conditions Meter: 0 to 50
Dimensions / Weight Main instrument: 257 x 76 x 53mm (10.1 x 3.0 x
2")
Weight 355g (12.5 oz.)
acquisition
o
C (32 to 122oF); 80% RH max.
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Function
Range
Resolution
Accuracy
Temp
-148°F to 20°F (3.0% reading + 4°F)
(type-K)
-20°F to
2501°F
1°≥1000
(3.0% reading + 2°F)
-100°C to 30°C
0.1°<1000
(3.0% reading + 2°C)
-30°C to
1372°C
(3.0% reading + 1°C)
IR Temp
-58 to -4°F
0.1°F/°C
±9.0°F / 5.0°C
-50 to -20°C
-4 to 932°F
0.1°F/°C
±2% reading or
±4°F/2°C
-20 to 500°C
Air Temp.
-4 to 140°F
0.1°F/°C
±(2% reading +
2°F/1°C)
-20 to 60°C
%RH
10% to 90%
0.1%RH
±2% RH
<10% and
>90%
0.1%RH
±3% RH
Wet Bulb
-6.88 to 140°F
0.1°F/°C
calculated
-21.6 to 60°C
Dew Point
-90.4 to 140°F
0.1°F/°C
calculated
-68 to 60°C
Warranty
Triplett / Jewell Instruments extends the following warranty to the original purchaser of
these goods for use. Triplett warrants to the original purchaser for use that the products
sold by it will be free from defects in workmanship and material for a period of (1) one
year from the date of purchase. This warranty does not apply to any of our products
which have been repaired or altered by unauthorized persons in any way or purchased
from unauthorized distributors so as, in our sole judgment, to injure their stability or
reliability, or which have been subject to misuse, abuse, misapplication, negligence,
accident or which have had the serial numbers altered, defaced, or removed.
Accessories, including batteries are not covered by this warranty
Copyright © 2021 Triplett
www.triplett.com
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