EXTESH HD550 User Guide

User Guide

Heavy Duty Psychrometer + IR Thermometer
Model HD550

Introduction

Congratulations on your purchase of the Extech HD550 Psychrometer. This handheld
meter measures and displays Air Temperature, Dew Point Temperature, and Wet Bulb
Temperature; Humidity in %RH, grains per pound, and grams per kilogram; and Surface
Temperature using the built-in IR thermometer. This meter is shipped fully tested and
calibrated and, with proper care and use, will provide years of reliable service.

Features

• Triple digital LCD display.

• Fast response, all data is calculated four times per second.

• Standard type K (NiCr-NiAl) Thermocouple input jack suitable for any style of type K

probe.

• Infrared thermometer to measure surface temperature.

• Red laser pointer included.

• LCD with Backlight.

• Automatic range selection.

• USB interface.

• Low battery indication.

• Auto Power off.

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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HD550 V1.0 08/09

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. UNITS button for Temperature/ Wet Bulb/ Dew Point/
%RH/GPP/ g/kg

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

Display Description

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

GPP

g/kg

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HD550 V1.0 08/09

Operation

Basic Measurements

1. Press the

2. Press the °C/°F button to change the units of measure from °C or °F.

3. The upper display will indicate Air Temperature, Wet Bulb Temperature or Dew Point

Temperature and % Relative Humidity, or Air Temperature and Grains Per Pound, or
grams per kilogram. Press the UNITS button to toggle between Air, WB or DP, and
%RH, GPP or g/kg.

4. The lower display will indicate Type K 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.

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

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.

button to turn power on.

button.

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Data Hold

1. Press the HOLD button (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

1. 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.

2. 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.

3. 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.

4. Press and Hold the MAX/MIN button for >2 seconds to exit the mode.

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:

Holding the IRT button and then pressing the

button to turn the power on. When

“disAPO” appears in the display, release the IRT button and the APO will be disabled.

Low Battery

When the battery reaches the minimum operating voltage the battery icon will appear in
the display. Replace the 9V battery when this occurs.

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.

Backlight

Press the backlight button to turn the backlight ON or OFF.
Note: Continuous use of the backlight function will reduce battery life.

USB Interface and Software

The HD550 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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HD550 V1.0 08/09

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.

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.

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Thermal Emissivity Table for Common Materials

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

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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 type / 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

Over range indication Dashes appears on the LCD
Low battery indication Battery symbol appears on the LCD

Power supply 9V Battery

Operating conditions Meter: 32 to 122

Dimensions / Weight Main instrument: 10.1 x 3.0 x 2" (257 x 76 x 53mm)

Weight 12.5 oz. (355g)

Range Specifications

Function Range Resolution Accuracy

Temp
(type-K)

-148°F to -20°F

-20°F to 2501°F

-100°C to -30°C

-30°C to 1372°C

IR Temp -58 to -4°F

-50 to -20°C

-4 to 932°F

-20 to 500°C

Air Temp. -4 to 140°F

-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

-21.6 to 60°C

Dew Point -90.4 to 140°F

-68 to 60°C

GPP

g/kg

0 to 999 GPP

0 to 160 g/kg

data acquisition (software HELP utility contains User Guide)

o

F (0 to 50oC); 80% RH max.

±(3.0% reading + 4°F)

1°≥1000

0.1°<1000

±(3.0% reading + 2°F)

±(3.0% reading + 2°C)

±(3.0% reading + 1°C)

0.1°F/°C ±9.0°F / 5.0°C

0.1°F/°C

0.1°F/°C

±2% reading or
±4°F/2°C

±(2% reading +
2°F/1°C)

0.1°F/°C

0.1°F/°C

0.1 GPP <100 GPP
1 GPP >100 GPP

Calculated from RH
and air temperature
measurements

0.1 g/kg<100 g/kg
1 g/kg>100 g/kg

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Warranty

EXTECH INSTRUMENTS CORPORATION (A FLIR COMPANY) warrants this instrument to be free of

defects in parts and workmanship for three years 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.

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 Care Department for
information on calibration services available for this product. Extech recommends that
annual calibrations be performed to verify meter performance and accuracy.

Technical support: Extension 200; E-mail: [e-mail]

Repair & Returns: Extension 210; E-mail: [e-mail]

Product specifications subject to change without notice

For the latest version of this User’s Guide, Software updates, and other

up-to-the-minute product information, visit our website: www.extech.com
Extech Instruments Corporation, 285 Bear Hill Rd., Waltham, MA 02451

Support line [phone]

Copyright © 2009 Extech Instruments Corporation (a FLIR company)

All rights reserved including the right of reproduction in whole or in part in any form.

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