Raytek ST25 Operating Manual

Noncontact Temperature Measurement

Manual

57560-1 Rev A West 11/02

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Infrared Thermometer for Automotive Diagnostics

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Infrarot-Thermometer für die Fahrzeugdiagnose

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Termômetro Infravermelho para Diagnósticos Automotivos

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Termómetro Infrarrojo para Diagnóstico Automotriz

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Thermomètre infrarouge pour le diagnostique automobile

Worldwide
Headquarters

Raytek Corporation

1201 Shaffer Rd. PO Box 1820
Santa Cruz, CA 95061-1820 USA
Tel: [phone]

1 831 458 1110

Fax: [phone]

[e-mail]

Raytek China Company

Beijing, China
Tel: [phone]
Fax: [phone]

[e-mail]

Raytek Japan, Inc.

Osaka, Japan
Tel: [phone]
Fax: [phone]

[e-mail]

South American Headquarters

Raytek do Brasil

Sorocaba, SP Brasil
Tel: [phone]
Fax: [phone]

[e-mail]

European Headquarters

Raytek GmbH

Berlin, Germany
Tel: [phone]
Fax: [phone]

[e-mail]

Raytek UK Ltd.

Milton Keynes, United Kingdom
Tel: [phone]
Fax: [phone]

[e-mail]

Raytek France

Palaiseau, France
Tel: [phone]
Fax: [phone]

[e-mail]

Worldwide Service

Raytek offers services including
emergency repairs and calibration.
For more information, contact
your local office or e-mail:
[e-mail]

www.raytek.com

for up-to-the-minute features

500 mSec (95% of reading)

8-14µm

Pre-set at 0.95

0 to 50ºC (32 to 120ºF)

10-90% RH noncondensing,

at 30 to 50ºC (86 to 122ºF)

-20 to 60ºC (-13 to 158ºF) without battery
360g (12oz) 205 x 160 x 55mm (8x6x2 in)

9V Alkaline or NiCd Battery

4 hrs w/laser, flashlight & backlight on

20 hrs w/laser, flashlight & backlight off

Response Time
Spectral Response
Emissivity
Ambient Operating Temp.
Relative Humidity

Storage Temperature
Weight/Dimensions
Power
Typical Battery Life

(Alkaline)

Specifications

Te mperature Range -32 to 535°C (-25 to 999°F)
Accuracy for target

temperatures
(assumes ambient
temperature of
23°C (73°F))

Repeatability

±0.5% or ≤ ±1ºC (±2ºF),

whichever is greater

Laser (Class II)

Typical Distance to Target
MAX Temp. Display
Display Hold (7 seconds)
LCD Backlit
Tripod Mounting
Removable base magnet
Work area illumination
Additional

Options/Accessories

SmartSight™ dual laser sighting system

Laser turns off above 40º C (104ºF)

ambient temperature

200 mm-600 mm (8 inches to 2 feet)

✓
✓
✓

0.25” 20 UNC threading

✓

Bright white LED (7100 millicandela)

Nylon Holster

NIST Calibration Certificate

–32 to –26°C (-25 to -15°F): ±3ºC (±5ºF)

-26 to -18°C(-15 to 0°F): ±2.5ºC (±4ºF)

-18 to 23°C (0 to 73°F): ±2ºC (±3ºF)
23° to 510ºC (73º to 950ºF):

±1% of reading or ±1ºC (±2ºF),

whichever is greater

Above 510ºC (950ºF): ±1.5% of reading

Distance to Spot (D:S)

0.2ºC (0.5ºF)

Display Resolution

Optimized for use at 8 inches

Approximately 16:1 at focus point

Te mperature Display ºC or ºF selectable

INTRODUCTION

Product Identification Label

Features

Your thermometer includes:

 Dual laser sighting
 LED Flashlight
 Wide temperature range
 MAX temperature display
 Back-lit graphic display
 Tripod mount
 Removable magnetic Base

 Durable, ergonomic construction

Options/Accessories

 Nylon Holster

 N.I.S.T./DKD Certification

Warning:

Do not point lasers directly at eye or indirectly off
reflective surfaces.

Cautions:

All models should be protected from the
following:
 EMF (Electro-Magnetic Fields) from engine

components closer than 125 mm (5
inches).

 Static electricity
 Thermal shock (caused by large or abrupt

ambient temperature changes—allow 30
minutes for unit to stabilize before use)

 Do not leave the unit on or near objects of

high temperature

Display

A) Low battery indicator (comes on when

battery is low)
B) °C/°F symbol
C) Maximum temperature value (continuously

updated while the unit is on)
D) Temperature display
E) Scan/Hold indicator

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F) Laser/Backlight/LED on indicator
G) Emissivity indicator
In the scan mode, the backlit LCD displays both
the current temperature (D) and maximum
temperature (C) in Celsius or Fahrenheit (B). The
unit will hold the last reading for 7 seconds after
the trigger is released; the word HOLD appears
(E). The presence of the battery icon (A)
indicates a low battery. The presence of a light
bulb (F) will indicate backlight and LED flashlight
are on. When trigger is pulled triangular icon will
be present indicating laser is on.

Introduction

We are confident you will find many uses for your
handheld non-contact thermometer. Compact,
rugged, and easy to use—just aim, pull the
trigger, and read the temperature in less than a
second. You can safely measure surface
temperatures of hot, hazardous, or hard-to-reach
objects without contact.

How to Operate the Unit

Measurement: Quick Start

To measure an object, point the unit at an object,
and pull the trigger. Try to merge the 2 laser dots
on your target into one dot. When using the
lasers, use them only for aiming. When sighting
an object, merge the 2 lasers into one for
optimum temperature reading. For more detailed
operating instructions, see “How to Accurately
Measure Temperature.”

How it Works

Infrared thermometers measure the surface

temperature of an object. The unit’s optics sense
emitted, reflected, and transmitted energy, which
are collected and focused onto a detector. The
unit’s electronics translate the information into a
temperature reading displayed on the unit. The
lasers are used for aiming purposes only.

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Switching °C and °F; Changing the
Battery; Laser/Backlight/LED On/Off

Before opening the unit’s handle to access the
battery and controls, use a Phillips head
screwdriver to remove the base magnet. To open
the unit’s handle, push the button near the trigger
on the underside of the unit, and pull the handle
down and forward.

To select °C or °F, slide the top switch (A) up for
Celsius and down for Fahrenheit. To activate the
lasers, backlight and LED flashlight, slide the
lower switch (B) down. Dual lasers and LED
flashlight will turn on when the trigger is pulled.
The lasers and LED flashlight will turn off when
the trigger is released. The backlight will remain
on for 7 seconds after the trigger is released.

To change the 9V battery, attach the battery to
the battery snaps with the positive side toward
the rear of the battery compartment.

How to Accurately Measure
Temperature

Laser Sighting

Laser sighting consists of 2 lasers. These lasers
are aimed at different angles. The point at which
the two laser points intersect (thermometer
focused) is 8 inches (200 mm). This is also the
optimum measuring distance.

inches: 0.5 inch). As the distance (D) from the
object decreases or increases, the spot size (S)
of the area measured by the unit becomes larger.
The spot sizes indicate 90%-encircled energy.

Emissivity

Emissivity is a term used to describe the energy­emitting characteristics of materials. Most organic
materials and painted or oxidized surfaces have
an emissivity of 0.95 (pre-set in the unit).
Inaccurate readings can result from measuring
shiny or polished metal surfaces. To
compensate, cover the surface to be measured
with masking tape or flat black paint. Allow time
for the tape or paint to reach the same
temperature as the material underneath it.
Measure the temperature of the tape or painted
surface.

To sight object being measured, press trigger to
turn on laser sight. Only one laser point should
be seen when at optimum measuring distance
(1). If two laser points are visible (2), adjust
distance of unit from object being measured. If it
is not possible to adjust the distance, see
Distance & Spot Size information.

Distance & Spot Size

The relationship between distance and spot size
is 16:1 at the focus point (200mm: 13mm or 8

Locating a Hot or Cold Spot

To find a hot or cold spot, aim the thermometer
outside the area of interest. Then scan across
the area with an up and down motion until you
locate the hot or cold spot.

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