Extech Instruments IR400 User manual

User Manual
InfraRed Thermometer
with Laser Pointer
MODEL IR400
Additional User Manual translations available at www.extech.com

IR400-en-US_v2.0 7/22
2
Introduction
Congratulations on your purchase of the Model IR400 IR Thermometer. The IR400 is capable of
non-contact (infrared) temperature measurements at the touch of a button. The built-in laser pointer
increases target accuracy while the backlit LCD and handy pushbuttons combine for convenient,
ergonomic operation. This meter is shipped fully tested and calibrated and, with proper use, will
provide years of reliable service.
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
Meter Description
Meter Description
1. Laser pointer beam
2. IR Sensor
3. Measurement Trigger
4. Battery Compartment
5. LCD Display
6. Pushbuttons
7. Handle Grip
Display Description
1. Temperature scan in progress (trigger held)
2. Last reading held (trigger released)
3. Laser pointer ON
4. Emissivity (0.95 fixed)
5. Max or MIN value displayed
6. Temperature display
7. Low battery icon (replace battery)
8. Temperature units

IR400-en-US_v2.0 7/22
3
Operating Instructions
Basic IR Measurements
1. Hold the meter by its handle and point it toward the surface to be measured.
2. Pull and hold the trigger to turn the meter on and begin testing. The temperature reading, the
flashing ‘SCAN’ icon, the unit of measure, and € = 0.95 will appear.
3. Release the Trigger and the reading will hold for approximately 10 seconds (HOLD will appear
on the LCD) after which the meter will automatically shut off.
Laser Pointer
1. When the trigger is pressed, the laser pointer will turn on and identify the spot being measured.
The icon on the display indicates that the pointer is on.
2. To turn the laser pointer off, press the button while scanning. Press the button again to
turn the pointer back on.
MAX - MIN
The Max / Min feature provides a means to display the highest (MAX) or lowest (MIN) temperature
measured during a scan.
1. While the trigger is pressed, press the MAX/MIN button. The “MAX” icon will appear and the
maximum measured temperature will appear in the display. The displayed temperature will not
change until a higher temperature is measured.
2. Press the MAX/MIN button again and the “MIN” icon will appear. The minimum temperature
only will be displayed
3. Press the MAX/MIN button again to return to a real time display.
Temperature Units C/F
To change the temperature units, press and release the trigger. Momentarily press the C/F button
and the temperature unit will change.
Backlight
When the meter is on, press the backlight button to turn the backlight on. Press the button again
to turn the backlight off.
Note: Constant use of the backlight feature will reduce battery life.
Over-Range Indication
If the temperature measurement exceeds the specified temperature range, the thermometer will
display “HI” or “LO” in place of a temperature reading.

IR400-en-US_v2.0 7/22
4
Field of View
The meter’s field of view is 8:1. For example, if the meter is 8 inches from the target (spot), the
diameter of the target must be at least 1 inch. Other distances are shown in the field of view
diagram. Note that measurements should normally be made as close as possible to the device
under test. The meter can measure from moderate distances, but the measurement may be affected
by external sources of light. In addition, the spot size may be so large that it encompasses surface
areas not intended to be measured.
Battery Replacement
When the battery symbol appears in the display, replace the meter’s 9V
battery. The battery compartment is located behind the panel that surrounds the
meter’s trigger. The panel can be pried open near the trigger and folded down as
shown in the diagram. Replace the 9V battery and close the battery compartment
cover.

IR400-en-US_v2.0 7/22
5
IR Measurement Notes
1. The object under test should be larger than the spot (target) size calculated by the field of view
diagram (printed on the side of the meter and in this guide).
2. Before measuring, be sure to clean surfaces that are covered with frost, oil, grime, etc.
3. If an object's surface is highly reflective, apply masking tape or flat black paint to the surface
before measuring. Allow time for the paint or tape to adjust to the temperature of the surface it is
covering.
4. Measurements can not be made through transparent surfaces such as glass. The surface
temperature of the glass will be measured.
5. Steam, dust, smoke, etc. can obscure measurements.
6. The meter automatically compensates for deviations in ambient temperature. However, it can
take up to 30 minutes for the meter to adjust to extremely wide changes.
7. 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.
Emissivity and IR Measurement Theory
IR Thermometers measure the surface temperature of an object. The thermometer’s optics sense
emitted, reflected, and transmitted energy. The thermometer’s electronics translate the information
into a temperature reading which is then displayed on the LCD.
The amount of IR energy emitted by an object is proportional to an object's temperature and its
ability to emit energy. This ability is known as emissivity and is based upon the material of the object
and its surface finish. Emissivity values range from 0.1 for a very reflective object to 1.00 for a flat
black finish. For the Model IR400, the emissivity is set to 0.95 which is correct for 90% of typical IR
measurement applications.

IR400-en-US_v2.0 7/22
6
Specifications
Display 3 ½ digit (1999 count) LCD with backlighting
Response time
Less than 1 second
Over range indication LCD will show “HI”/”LO”
Polarity Automatic (no indication for positive polarity); Minus (-) sign for negative
polarity.
Emissivity 0.95 fixed value
Field of view D/S = Approx. 8:1 ratio (D = distance, S = spot)
(90% encircled energy at the focal point)
Diode Laser Output <1mW, Wavelength 630 to 670nm, Class 2 (II) Laser product
Spectral response 6 to 14µm
Auto power off Automatic shut off after 10 seconds, approx.
Operating temperature
32oF to 122oF (0oC to 50oC)
Storage temperature
-4oF to 140oF (-20oC to 60oC)
Relative humidity 10% to 90%RH operating, <80%RH storage
Power supply 9V battery, NEDA 1604A or IEC 6LR61, or equivalent
Weight
6.3 oz (180 g)
Dimensions 3.2 x 1.6 x 6.3” (82 x 41.5 x 160mm)
Range
Resolution
Accuracy
-4F to 20°F
-20C to -7°C 0.1°F/°C ± 7.5°F (4°C)
20 to 630°F
-7C to 343°C 0.1°F/°C ± (2% of reading + 4°F [2°C])
Note: Accuracy is given at 64 °F to 82 °F (18 °C to 28 °C), less than 80%RH

IR400-en-US_v2.0 7/22
7
Three-year Warranty
Teledyne FLIR warrants this Extech brand 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). To view the full warranty text please visit: http://www.extech.com/support/warranties.
Calibration and Repair Services
Teledyne FLIR offers calibration and repair services for the Extech brand products we sell. We
offer NIST traceable calibration for most of our products. Contact us for information on calibration and
repair availability, refer to the contact information below. Annual calibrations should be performed to
verify meter performance and accuracy. Product specifications are subject to change without notice.
Please visit our website for the most up-to-date product information: www.extech.com.
Contact Customer Support
Customer Support Telephone List: https://support.flir.com/contact
Calibration, Repair, and Returns: [e-mail]
Technical Support: https://support.flir.com
Copyright ©2022 Teledyne FLIR Commercial Systems, Inc.
All rights reserved including the right of reproduction in whole or in part in any form
www.extech.com
This document does not contain any export-controlled information