Extech Instruments 42540 User manual

User’s Manual
High Temperature InfraRed Thermometer
with Laser Pointer
MODEL 42540
Introduction
Congratulations on your purchase of the Model 42540 IR Thermometer. The 42540 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 push-
buttons combine for convenient, ergonomic operation. Proper use and care of this meter
will provide years of reliable service.

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Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and
workmanship for one year from date of shipment (a six month limited warranty applies on 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 at
www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’ to request an RA number). 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.
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
Specifications
Infrared Thermometer Specifications
Range / Resolution -58 to 1400oF (-50 to 760oC) 0.1oC/F
Accuracy ±(2% + 2o) at <932oF (500oC)
± (2.5% + 5o) at > 932oF (500oC)
Note: Accuracy is specified for the following ambient
temperature range: 64 to 82°F (18 to 28°C)
Emissivity 0.95 fixed value
Field of View D/S = Approx. 12:1 ratio (D = distance, S = spot)
Laser power Less than 1mW
Spectral response 6 to 14 µm (wavelength)
General Specifications
Display 3½ digit backlit LCD display with function indicators
Display rate 1 second approx.
Operating Temperature 32°F to 122°F (0°C to 50°C)
Operating Humidity Max. 80% RH.
Power Supply 9V battery
Automatic Power Off Meter shuts off automatically after 6 seconds
Weight 10.2 oz. / 290g
Dimensions 3.9 x 2.2 x 9.0” (100 x 56 x 230mm)

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Meter Description
1. Laser pointer beam
2. IR Sensor
3. Measurement Trigger
4. Battery Compartment
5. LCD Display
6. Push-buttons
7. Handle Grip
Operating Instructions
1. Hold the meter by its Handle Grip and point it toward the surface to be measured.
2. Pull and hold the Trigger to turn the meter on and begin testing. The display will light if
the battery is fresh. Replace the battery if the display does not light.
3. While continuing to pull the Trigger:
a. Push the laser button to turn on the laser pointer. When the laser is on, the
laser icon will appear on the LCD over the temperature reading. Aim the red
beam at the point of test (pressing the laser button again turns the laser off).
b. Select the temperature units using the oCor oFbutton.
c. Push the backlight button to turn on the LCD backlight function.
4. Release the Trigger (the reading will hold for approximately 6 seconds) and the meter
will automatically shut off.
Over-range Indicator
If the temperature measurement exceeds 1400°F (760°C), the thermometer will display
dashes in place of a temperature reading.
Measurement Notes
1. The object under test should be larger than the spot (target) size calculated by the field
of view diagram.
2. If the surface of the object under test is covered with frost, oil, grime, etc., clean before
taking measurements.
3. If an object's surface is highly reflective, apply masking tape or flat black paint to the
surface before measuring.
4. The meter may not make accurate measurements through transparent surfaces such
as glass.
5. Steam, dust, smoke, etc. can obscure measurements.
6. The meter compensates for deviations in ambient temperature. It can, however, take
up to 30 minutes for the meter to adjust to extremely wide ambient temperature
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.
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Support Hotline [phone]
Tech support: Ext. 200; Email: [e-mail]
Repair/Returns: Ext. 210; Email: [e-mail]
Website: www.extech.com
Field of View
The meter’s field of view is 12:1. For example, if the meter is 24 inches from the target
(spot), the diameter of the target must be at least 2 inches. Other distance ratios are
shown in the field of view diagram.
Note that measurements should normally be made less than 2 feet from the target. The
meter can measure from further 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 low battery symbol appears on the LCD, 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.
Calibration and Repair Services
Extech offers complete repair and calibration services for all of the products we sell. For
periodic calibration, NIST certification or repair of any Extech product, call customer
service for details on services available. Extech recommends that calibration be performed
on an annual basis to ensure calibration integrity.
Copyright ©2004 Extech Instruments Corporation.
All rights reserved including the right of reproduction in whole or in part in any form.
1”
2”
Distance to Ob
j
ect
Diameter of Spot 4”
6” 12” 24” 48”
0.5”