Optris CSlaser 2M, CSlaser LT Operating Manual

optris

®

CSlaser

LT/ hs LT/ 2M/ G5

Infrared-thermometer

Operator‘s Manual

Optris GmbH

Ferdinand-Buisson-Str. 14
13127 Berlin
Germany

Tel.: [phone]
Fax: [phone]

E-mail: [e-mail]
Internet: www.optris.global

-Table of Contents 3-

Table of Contents

Table of Contents ............................................................................................................................................. 3

1 General Information ................................................................................................................................. 6

1.1 Description ....................................................................................................................................... 6

1.2 Warranty ........................................................................................................................................... 7

1.3 Scope of Supply ............................................................................................................................... 7

1.4 Maintenance ..................................................................................................................................... 8

1.5 Model Overview ................................................................................................................................ 8

1.6 Factory Default Settings ................................................................................................................... 9

2 Technical Data ........................................................................................................................................ 11

2.1 General Specifications ................................................................................................................... 11

2.2 Electrical Specifications .................................................................................................................. 12

2.3 Measurement Specifications .......................................................................................................... 13

2.4 Optical Charts ................................................................................................................................. 15

-4 -

3 Mechanical Installation .......................................................................................................................... 24

4 Accessories ............................................................................................................................................ 25

4.1 Mounting Brackets .......................................................................................................................... 25

4.2 Air Purge Collar .............................................................................................................................. 26

4.3 Water Cooled Housing ................................................................................................................... 27

4.4 CoolingJacket und CoolingJacket Advanced ................................................................................. 28

4.5 Outdoor protective housing ............................................................................................................ 29

5 Electrical Installation ............................................................................................................................. 30

5.1 Cable Connections ......................................................................................................................... 30

5.2 Analog Mode .................................................................................................................................. 33

5.3 Digital Mode ................................................................................................................................... 33

5.4 Digital and Analog Mode combined ............................................................................................... 34

5.5 Maximum Loop Impedance ............................................................................................................ 35

6 Emissivity Setting .................................................................................................................................. 36

-Table of Contents 5-

7 Laser Sighting ........................................................................................................................................ 37

8 Software CompactConnect ................................................................................................................... 39

8.1 Installation ...................................................................................................................................... 39

8.2 Communication Settings ................................................................................................................ 40

8.3 Digital Command Set ..................................................................................................................... 41

9 Basics of Infrared Thermometry........................................................................................................... 42

10 Emissivity ............................................................................................................................................... 43

10.1 Definition......................................................................................................................................... 43

10.2 Determination of unknown Emissivities .......................................................................................... 43

10.3 Characteristic Emissivities.............................................................................................................. 44

Appendix A – Emissivity Table Metals ......................................................................................................... 45

Appendix B – Emissivity Table Non Metals ................................................................................................. 47

Appendix C – Smart Averaging ..................................................................................................................... 48

Appendix D - Declaration of Conformity ...................................................................................................... 49

-6 -

The CSlaser sensing head is a sensitive optical system. Please use only the thread for
mechanical installation.

 Avoid abrupt changes of the ambient temperature.
 Avoid mechanical violence on the head – this may destroy the system (expiry of warranty).

 If you have any problems or questions, please contact our service department.

Read the manual carefully before the initial start-up. The producer reserves the right to change
the herein described specifications in case of technical advance of the product.

► All accessories can be ordered according to the referred part numbers in brackets [ ].

1 General Information

1.1 Description

Thank you for choosing the optris® CSlaser infrared thermometer.
The sensors of the optris CSlaser series are noncontact infrared temperature sensors.
They calculate the surface temperature based on the emitted infrared energy of objects [►9 Basics of
Infrared Thermometry]. An integrated double laser aiming helps to mark the measurement spot on the
object surface. This lies within the two laser points.
The sensor housing of the CSlaser head is made of stainless steel (IP65/ NEMA-4 rating).

-General Information 7-

1.2 Warranty

Each single product passes through a quality process. Nevertheless, if failures occur please contact the
customer service at once. The warranty period covers 24 months starting on the delivery date. After the
warranty is expired the manufacturer guarantees additional 6 months warranty for all repaired or substituted
product components. Warranty does not apply to damages, which result from misuse or neglect. The
warranty also expires if you open the product. The manufacturer is not liable for consequential damage or in
case of a non-intended use of the product.
If a failure occurs during the warranty period the product will be replaced, calibrated or repaired without
further charges. The freight costs will be paid by the sender. The manufacturer reserves the right to
exchange components of the product instead of repairing it. If the failure results from misuse or neglect the
user has to pay for the repair. In that case you may ask for a cost estimate beforehand.

1.3 Scope of Supply

 CSlaser
 Mounting nut and mounting bracket (fixed)
 Connection cable (optional at connector version)
 Operators manual

-8 -

Never use cleaning compounds which contain solvents (neither for the lens nor for the housing).

Model

Model code

Measurement range

Spectral
response

Typical applications

CSlaser
LT

-30 to 1000 °C

8-14 µm
non-metallic surfaces

hs LT

-20 to 150 °C

0,025 K resolution

CSlaser 2M
2ML

250 to 800 °C

1,6 µm

metals and ceramic surfaces
2MH

385 to 1600 °C

CSlaser G5

G5HF

200 to 1650 °C

5,0 µm

glass

1.4 Maintenance

Lens cleaning: Blow off loose particles using clean compressed air. The lens surface can be cleaned with a

soft, humid tissue (moistened with water) or a lens cleaner (e.g. Purosol or B+W Lens Cleaner).

1.5 Model Overview

The sensors of the CSlaser series are available in the following basic versions:

In the following chapters of this manual you will find only the short model codes.

-General Information 9-

Signal output object temperature

4-20 mA

Emissivity (switches)

0,970 [LT/ hs LT]
1,000 [2ML/ 2MH/ G5HF]

Emissivity (via software)

1,000

Transmissivity

1,000

Average time (AVG)

0,2 s [LT, hs LT]
0,1 s [2ML, 2MH, G5HF]

Smart Averaging

inactive [LT]
active [hs LT, 2ML, 2MH, G5HF]

Peak hold

inactive

Valley hold

inactive

LT

hs LT

2ML

2MH

G5HF

Lower limit temperature range [°C]

0

-20

250

385

200

Upper limit temperature range [°C]

500

150

800

1600

1650

Lower limit signal output

4 mA

Upper limit signal output

20 mA

Temperature unit

°C

Ambient temperature compensation

internal head temperature probe

Laser

active

1.6 Factory Default Settings

The unit has the following presetting at time of delivery:

-10 -

Smart Averaging means a dynamic average adaptation at high signal edges.
[Activation via software only].
►Appendix C – Smart Averaging

-Technical Data 11-

Environmental rating

IP65 (NEMA-4)

Ambient temperature 1)

-20...85 °C

Storage temperature

-40...85 °C

Relative humidity

10...95 %, non condensing

Material

stainless steel

Dimensions

100 mm x 50 mm, M48x1,5

Weight

600 g

Cable length
(on connector version only)

3 m, 8 m, 15 m
Cable diameter

5 mm

Ambient temperature cable

max. 105 °C [High temperature cable (optional): 180 °C]

Vibration

IEC 68-2-6: 3G, 11 – 200Hz, any axis

Shock

IEC 68-2-27: 50G, 11ms, any axis

Software (optional)

CompactConnect

2 Technical Data

2.1 General Specifications

1)

Laser will turn off automatically at ambient temperatures >50 °C.

-12 -

Power Supply

5–30 VDC

Current draw (laser)

45 mA @ 5 V
20 mA @ 12 V
12 mA @ 24 V

Aiming laser

635 nm, 1 mW, On/ Off via external switch (needs to be installed by user before start-up)
or software

Output/ analog

4–20 mA current loop

Alarm output

Programmable open collector output at RxD pin [0-30 V/ 500 mA]

Output impedance

max. loop resistance 1000 Ω (in dependence on supply voltage)

Output/ digital

uni-/ bidirectional, 9,6 kBaud, 0/3 V digital level
USB optional

2.2 Electrical Specifications

-Technical Data 13-

LT

hs LT

Temperature range (scalable)

-30...1000 °C

-20...150 °C

Spectral range

8...14 µm

Optical resolution

50:1

System accuracy

1), 2)

±1,0 °C or ±1,0 %

Repeatability

1), 2)

±0,5 °C or ±0,5 %

±0,3 °C or ±0,3 %

Temperature resolution (NETD)

0,1 K 2)

0,025 K 4)

Response time (90% signal)

150 ms

Warm-up time

10 min

Emissivity/ Gain

0,100...1,100 (adjustable via switches on sensor or via software)

IR window correction

0,100...1,100 (adjustable via software)

Signal processing

Average, peak hold, valley hold, extended hold functions with threshold and

hysteresis (adjustable via software)

2.3 Measurement Specifications

1)

at ambient temperature 235 °C; whichever is greater

2)

at object temperatures >0 °C

3)

 = 1/ Response time 1 s

4)

at T

>20°C and time constant > 0,2 s

Obj

-14 -

2ML

2MH

G5HF

Temperature range (scalable)

250...800 °C

385...1600 °C

200…1650 °C

Spectral range

1,6 µm

5,0 µm

Optical resolution

150:1

300:1

45:1

System accuracy 1)

±(0,3 % of reading +2 °C)

3)

±1 °C or ±1 % 2)

Repeatability 1)

±(0,1 % of reading +1 °C)

3)

±0,5 °C or ±0,5 % 2)

Temperature resolution (NETD)

0,1 K 2)

Response time (90% signal)

10 ms

30 ms

Warm-up time

-

10 min

Emissivity/ Gain

0,100...1,100 (adjustable via switches on sensor or via software)

IR window correction

0,100...1,100 (adjustable via software)

Signal processing

Average, peak hold, valley hold, extended hold functions with threshold and

hysteresis (adjustable via software)

1)

at ambient temperature 235 °C; whichever is greater

2)

at object temperatures >0 °C

3)

 = 1/ Response time 1 s

-Technical Data 15-

The size of the measuring object and the optical resolution of the infrared thermometer
determine the maximum distance between sensing head and measuring object.
In order to prevent measuring errors the object should fill out the field of view of the optics
completely.
Consequently, the spot should at all times have at least the same size like the object or should
be smaller than that.

2.4 Optical Charts

The following optical charts show the diameter of the measuring spot in dependence on the distance
between measuring object and sensing head. The spot size refers to 90 % of the radiation energy.
The distance is always measured from the front edge of the sensing head.

As an alternative to the optical diagrams, the spot size calculator can also be used on the optris website

http://www.optris.com/spot-size-calculator.

D = Distance from front of the sensing head to the object
S = Spot size

-16 -

LT
Optics: CF1

D:S (focus distance) = 50:1/ 1,4mm@ 70mm
D:S (far field) = 1,5:1

LT
Optics: SF

D:S (focus distance) = 50:1/ 24mm@ 1200mm
D:S (far field) = 20:1

-Technical Data 17-

LT
Optics: CF2

D:S (focus distance) = 50:1/ 3mm@ 150mm
D:S (far field) = 6:1

LT
Optics: CF3

D:S (focus distance) = 50:1/ 4mm@ 200mm
D:S (far field) = 8:1

-18 -

2MH
Optics: FF

D:S (focus distance) = 300:1
12mm@ 3600mm
D:S (far field) = 115:1

2ML
Optics: FF

D:S (focus distance) = 150:1
24mm@ 3600mm
D:S (far field) = 84:1

LT
Optics: CF4

D:S (focus distance) = 50:1/ 9mm@ 450mm
D:S (far field) = 16:1

-Technical Data 19-

2MH
Optics: CF2

D:S (focus distance) = 300:1
0,5mm@ 150mm
D:S (far field) = 7,5:1

2ML
Optics: CF2

D:S (focus distance) = 150:1
1,0mm@ 150mm
D:S (far field) = 7:1

2MH
Optics: SF

D:S (focus distance) = 300:1
3,7mm@ 1100mm
D:S (far field) = 48:1

2ML
Optics: SF

D:S (focus distance) = 150:1
7,3mm@ 1100mm
D:S (far field) = 42:1

-20 -

2MH
Optics: CF4

D:S (focus distance) = 300:1
1,5mm@ 450mm
D:S (far field) = 22:1

2MH
Optics: CF4

D:S (focus distance) = 150:1
3,0mm@ 450mm
D:S (far field) = 20:1

2MH
Optics: CF3

D:S (focus distance) = 300:1
0,7mm@ 200mm
D:S (far field) = 10:1

2ML
Optics: CF3

D:S (focus distance) = 150:1
1,3mm@ 200mm
D:S (far field) = 10:1

-Technical Data 21-

G5HF
Optics: CF1

D:S (focus distance) = 45:1
1,6mm@ 70mm
D:S (far field) = 3:1

G5HF
Optics: SF

D:S (focus distance) = 45:1
27mm@ 1200mm
D:S (far field) = 25:1

-22 -

G5HF
Optics: CF3

D:S (focus distance) = 45:1
4,5mm@ 200mm
D:S (far field) = 8:1

G5HF
Optics: CF2

D:S (focus distance) = 45:1
3,4mm@ 150mm
D:S (far field) = 6:1

-Technical Data 23-

G5HF
Optics: CF4

D:S (focus distance) = 45:1
10mm@ 450mm
D:S (far field) = 15:1

-24 -

Make sure to keep the optical path clear of any obstacles.

3 Mechanical Installation

The CSlaser is equipped with a metric M48x1,5 thread and can be installed either directly via the sensor
thread or with help of the supplied mounting nut (standard) and fixed mounting bracket (standard) to a
mounting device available.

CSlaser sensing head

-Accessories 25-

For an exact sensor alignment to the object
please activate the integrated double laser.

[►7 Laser Sighting]

4 Accessories

4.1 Mounting Brackets

Mounting bracket, adjustable in two axes [ACCTLAB]

Mounting bracket, adjustable in one axis [ACCTLFB]

-26 -

The needed amount of air (approx. 2...10 l/ min.)
depends on the application and the installation
conditions on-site.

4.2 Air Purge Collar

The lens must be kept clean at all times from dust, smoke, fumes and other contaminants in order to avoid
reading errors. These effects can be reduced by using an air purge collar. Make sure to use oil-free,
technically clean air only.

Air purge collar [ACCTLAP]
Hose connection: 6x8 mm
Thread (fitting): G 1/8 inch

-Accessories 27-

To avoid condensation on the optics an air purge
collar is recommended.

Water flow rate: approx. 2 l/ min

(Cooling water temperature should not exceed
30 °C)

4.3 Water Cooled Housing

Water cooled housing [ACCTLW]
Hose connection: 6x8 mm
Thread (fitting): G 1/8 inch

The CSlaser can be used at ambient temperatures up to 85 °C without cooling. For applications, where the
ambient temperature can reach higher values, the usage of the optional water cooled housing is
recommended (operating temperature up to 175 °C). The sensor should be equipped with the optional high
temperature cable (operating temperature up to 180 °C).

-28 -

For higher temperatures (up to 180 °C) the CoolingJacket is provided
for CSlaser.

Order No.: ACCTLCJ

For even higher temperatures (up to 315 °C) the
CoolingJacket Advanced is provided for
CSlaser.

Order No.: ACCTLCJA

For detailed information see installation manual.

4.4 CoolingJacket und CoolingJacket Advanced

-Accessories 29-

Figure 1: Outdoor protective housing for CSlaser LT
with integrated heater, incl. prot. window (ZnS) and
air purge collar/ 24 V DC

Figure 2: Outdoor protective housing with wall
mount

For detailed information see installation manual.

4.5 Outdoor protective housing

The CSlaser LT models and the USB server can also be used for outdoor applications by using the outdoor
protective housing (Order No.: ACCTLOPH24ZNS).

-30 -

The basic version is supplied without connection cable. To connect the
CSlaser please open at first the sensor backplane (4 screws). Please use a
4-wire shielded cable which you have to conduct through the cable gland.
During assembling please make sure the shield gets a safe electrical
contact to the sensor housing. For an easier connection the terminal block
can be removed from the PCB by pulling off.

5 Electrical Installation

5.1 Cable Connections

Basic version

Shield connection to cable gland

-Electrical Installation 31-

This version has a connector plug integrated in the sensor backplane.
Therefore an opening of the sensor for cable assembling is not necessary.
Please use the original ready-made, fitting connection cables which are
optionally available. If you want to use own cables please note the pin
assignment of the connector (see next page).

Connector version

Power supply

Please use a power supply unit with an output voltage of 5–30 VDC which can supply 100 mA.

-32 -

Designation (sensor terminal block)

RXD Receive data (digital)
TXD Transmit data (digital)
LOOP + Current loop (+)
LOOP – Current loop (–)
LASER – Power supply laser (–)
LASER + Power supply laser (+)

Above the terminal block you will find two rotary switches for
[►6 Emissivity Setting].

Sensor back side with terminal block

Pin assignment of connector plug (connector version only)

PIN designation wire color (original sensor cable)
1 TXD yellow
2 LOOP – brown
3 LOOP + white
4 RXD green
5 LASER – grey
6 LASER + pink
7 –

Connector plug (Outer view)

-Electrical Installation 33-

5.2 Analog Mode

If the CSlaser is used as analog device the sensor provides beside the 4-20 mA signal in addition an alarm
output (open-collector) on the RxD pin. To activate the alarm output and set the alarm threshold value the
software (optional) is needed. The supply line for the sighting laser must be led via a switch or

pushbutton, which has to be installed max. 2 m away from installation site of the sensor.

5.3 Digital Mode

In the digital mode the sensor and the laser will be powered via the 5 V from USB interface. The activation/
deactivation of the laser has to be made via the software.

-34 ­For a digital communication the optional USB programming kit is

required. Please connect each wire of the USB adapter cable with
the same coloured wire of the sensor cable by using the terminal
block. Press with a screw driver as shown in the picture to loose a
contact.
Alternatively the USB cable can also be connected directly on the
sensor [►5.1 Cable Connections].

The sensor is offering two ways of digital communication:

 bidirectional communication (sending and receiving data)
 unidirectional communication (burst mode – the sensor is sending data only)

5.4 Digital and Analog Mode combined

The CSlaser are able to work in the digital mode and simultaneously as analog device (4-20 mA).
In this case the sensor will be powered by the USB interface (5 V).

-Electrical Installation 35-

5.5 Maximum Loop Impedance

The maximum impedance of the current loop depends on the supply voltage level:

-36 -

6 Emissivity Setting

After opening of the sensor backplane [►5.1 Cable Connections] both of the emissivity switches are
accessible.

For an emissivity setting of 1,00 please turn both switches to 0. Values below 0,10 are not adjustable. For all
other switch positions the following applies: 0, S1 S2.
Therefore the adjustment range is 0,10...1,09.

Example: ε = 0,84 S1=8
S2=4

If you use the software (optional) please consider that the emissivity
switches can be activated/ deactivated in the software menu Device/
Device setup. At time of delivery the switches are active.
The emissivity set in the software interacts as a factor to the emissivity
set on the unit. Thus the adjustment range increases to 0,100...1,199.

Example: ε

Software

= 0,952 x ε

= 0,82 (S1=8/ S2=2)

Sensor

Therefore the effective emissivity is: 0,781.

-Laser Sighting 37-

Do not point the laser directly at the eyes of persons or animals! Do not stare into the laser
beam. Avoid indirect exposure via reflective surfaces!

The two laser points don’t mark the exact measurement spot. They just are for orientation only.
The exact size of the measurement spot can be found in the optical charts
[►2.4 Optical Charts].

 At ambient temperatures >50 °C the laser will be switched off automatically.
 The laser should only be used for sighting and positioning of the sensor. A permanent use of

the laser can reduce the lifetime of the laser diodes.

 Furthermore, in a permanent use of the laser, the measurement accuracy can be affected.

7 Laser Sighting

The CSlaser has an integrated double laser aiming which helps for the alignment of
the sensor. The measuring spot is located within the two laser points. At the focus
point of the according optics [►2.4 Optical Charts] both lasers are crossing and
showing as one dot the minimum spot. This enables an alignment of the sensor to the
object.

-38 -

The supply line for the sighting laser must be led via a switch or pushbutton, which has to be
installed max. 2 m away from installation site of the sensor.

The laser can be activated/ deactivated via this, by the user on site to be installed switch, or via the
software.

-Software CompactConnect 39-

Minimum system requirements:

 Windows 7, 8, 10
 USB interface
 Hard disc with at least 30 MByte free space
 At least 128 MByte RAM
 CD-ROM drive

You will find a detailed software manual on the CD.

8 Software CompactConnect

8.1 Installation

Insert the installation CD into the according drive on
your computer. If the autorun option is activated the
installation wizard will start automatically.
Otherwise please start CDsetup.exe from the CD­ROM. Follow the instructions of the wizard until the
installation is finished.

The installation wizard will place a launch icon on the desktop and in the start menu:

[Start]\Programs\CompactConnect.
If you want to uninstall the software from your system please use the uninstall icon in the start menu.

Main Features:

 Graphic display for temperature trends and automatic data logging

for analysis and documentation

 Complete sensor setup and remote controlling
 Adjustment of signal processing functions
 Programming of outputs and functional inputs

-40 -

8.2 Communication Settings

Serial Interface

Baud rate: 9600 baud
Data bits: 8
Parity: none
Stop bits: 1
Flow control: off

Protocol

All sensors of the CSlaser series are using a binary protocol. To get a fast communication the protocol has
no additional overhead with CR, LR or ACK bytes.
To power the sensor the control signal “DTR“ has to be reset.

-Software CompactConnect 41-

CSlaser/ CSvideo Commands

Decimal HEX Binary/ ASCII Command Data Answer Result Unit

1 0x01 binary READ Temp - Target no byte1 byte2 = (byte1 x 256 + byte2 - 1000) / 10 °C
2 0x02 binary READ Temp - Head no byte1 byte2 = (byte1 x 256 + byte2 - 1000) / 10 °C
3 0x03 binary READ current Temp - Target no byte1 byte2 = (byte1 x 256 + byte2 - 1000) / 10 °C
4 0x04 binary READ Emissivity no byte1 byte2 = (byte1 x 256 + byte2) / 1000
5 0x05 binary READ Transmission no byte1 byte2 = (byte1 x 256 + byte2) / 1000

9 0x09 binary READ Processor Temperature no byte1 = (byte1 x 256 + byte2 - 1000) / 10
14 0x0E binary READ Serial number no byte1 byte2 byte3 = byte1 x 65536 + byte2 x 256 + byte3
15 0x0F binary READ FW Rev. no byte1 byte2 = byte1 x 256 + byte2
16 0x10 binary READ Laser status no byte1 0 = off/ 1 = on
17 0x11 binary READ Emissivity switch setting no

HEX value (e.g. 0x58) = Switch setting
(e.g. SW1=5/ SW2=8 -> Eps. = 0,58)

129 0x81 binary SET DAC mA byte1 byte1 byte 1= mA x 10 (z.B. 4mA = 4 x 10=40) °C
130 0x82 binary RESET of DAC mA output
132 0x84 binary SET Emissivity byte1 byte2 byte1 byte2 = (byte1 x 256 + byte2) / 1000
133 0x85 binary SET Transmission byte1 byte2 byte1 byte2 = (byte1 x 256 + byte2) / 1000
144 0x90 binary SET Laser byte1 byte1 0 = off/ 1 = on

Temperature calculation at CSlaser hs: (byte1 x 256 + byte2 - 10000) / 100

EXAMPLES (all bytes in HEX)
Readout of object temperature

Send: 01 Command for readout of object temperature
Receive: 04 D3 Object temperature in tenth degree + 1000 04 D3 = dec. 1235

1235 - 1000 = 235

235 / 10 = 23,5 °C

Readout of object temperature (at hs version)

Send: 01 Command for readout of object temperature
Receive: 30 3E Object temperature in hundredth degree + 10000 30 3E = dec. 12350

12350 - 10000 = 2350
2350 / 100 = 23.50 °C

Set of emissivity

Send:

84 03 B6 03B6 = dec. 950

Receive: 03 B6

950 / 1000 = 0,950

8.3 Digital Command Set

-42 -

9 Basics of Infrared Thermometry

Depending on the temperature each object emits a certain amount of infrared radiation. A change in the
temperature of the object is accompanied by a change in the intensity of the radiation. For the measurement
of “thermal radiation” infrared thermometry uses a wave-length ranging between 1 µm and 20 µm.
The intensity of the emitted radiation depends on the material. This material contingent constant is described
with the help of the emissivity which is a known value for most materials (►10 Emissivity).

Infrared thermometers are optoelectronic sensors. They calculate the surface temperature on the basis of
the emitted infrared radiation from an object. The most important feature of infrared thermometers is that
they enable the user to measure objects contactless. Consequently, these products help to measure the
temperature of inaccessible or moving objects without difficulties. Infrared thermometers basically consist of
the following components:

 lens
 spectral filter
 detector
 electronics (amplifier/ linearization/ signal processing)

The specifications of the lens decisively determine the optical path of the infrared thermometer, which is
characterized by the ratio Distance to Spot size.
The spectral filter selects the wavelength range, which is relevant for the temperature measurement. The
detector in cooperation with the processing electronics transforms the emitted infrared radiation into electrical
signals.

-Emissivity 43-

10 Emissivity

10.1 Definition

The intensity of infrared radiation, which is emitted by each body, depends on the temperature as well as on
the radiation features of the surface material of the measuring object. The emissivity (ε – Epsilon) is used as
a material constant factor to describe the ability of the body to emit infrared energy. It can range between 0

and 100 %. A “blackbody” is the ideal radiation source with an emissivity of 1,0 whereas a mirror shows an

emissivity of 0,1.
If the emissivity chosen is too high, the infrared thermometer may display a temperature value which is much
lower than the real temperature – assuming the measuring object is warmer than its surroundings. A low
emissivity (reflective surfaces) carries the risk of inaccurate measuring results by interfering infrared radiation
emitted by background objects (flames, heating systems, chamottes). To minimize measuring errors in such
cases, the handling should be performed very carefully and the unit should be protected against reflecting
radiation sources.

10.2 Determination of unknown Emissivities

► First, determine the actual temperature of the measuring object with a thermocouple or contact sensor.

Second, measure the temperature with the infrared thermometer and modify the emissivity until the
displayed result corresponds to the actual temperature.

► If you monitor temperatures of up to 380 °C you may place a special plastic sticker (emissivity dots – part

number: ACLSED) onto the measuring object, which covers it completely. Now set the emissivity to 0,95

-44 ­and take the temperature of the sticker. Afterwards, determine the temperature of the adjacent area on

the measuring object and adjust the emissivity according to the value of the temperature of the sticker.

► Cove a part of the surface of the measuring object with a black, flat paint with an emissivity of 0,98. Adjust

the emissivity of your infrared thermometer to 0,98 and take the temperature of the colored surface.
Afterwards, determine the temperature of a directly adjacent area and modify the emissivity until the
measured value corresponds to the temperature of the colored surface.

CAUTION: On all three methods the object temperature must be different from ambient temperature.

10.3 Characteristic Emissivities

In case none of the methods mentioned above help to determine the emissivity you may use the emissivity
tables ►Appendix A – Emissivity Table Metals and Appendix B – Emissivity Table Non Metals. These
are average values, only. The actual emissivity of a material depends on the following factors:

 temperature
 measuring angle
 geometry of the surface
 thickness of the material
 constitution of the surface (polished, oxidized, rough, sandblast)
 spectral range of the measurement
 transmissivity (e.g. with thin films)

-Appendix A – Emissivity Table Metals 45-

1,0 µm 1,6 µm 5,1 µm 8-14 µm

Aluminium non oxidized 0,1-0,2 0,02-0,2 0,02-0,2 0,02-0,1

polished 0,1-0,2 0,02-0,1 0,02-0,1 0,02-0,1
roughened 0,2-0,8 0,2-0,6 0,1-0,4 0,1-0,3
oxidized 0,4 0,4 0,2-0,4 0,2-0,4

Brass polished 0,35 0,01-0,05 0,01-0,05 0,01-0,05

roughened 0,65 0,4 0,3 0,3
oxidized 0,6 0,6 0,5 0,5

Copper polished 0,05 0,03 0,03 0,03

roughened 0,05-0,2 0,05-0,2 0,05-0,15 0,05-0,1

oxidized 0,2-0,8 0,2-0,9 0,5-0,8 0,4-0,8
Chrome 0,4 0,4 0,03-0,3 0,02-0,2
Gold 0,3 0,01-0,1 0,01-0,1 0,01-0,1
Haynes alloy 0,5-0,9 0,6-0,9 0,3-0,8 0,3-0,8
Inconel electro polished 0,2-0,5 0,25 0,15 0,15

sandblast 0,3-0,4 0,3-0,6 0,3-0,6 0,3-0,6

oxidized 0,4-0,9 0,6-0,9 0,6-0,9 0,7-0,95
Iron non oxidized 0,35 0,1-0,3 0,05-0,25 0,05-0,2

rusted 0,6-0,9 0,5-0,8 0,5-0,7

oxidized 0,7-0,9 0,5-0,9 0,6-0,9 0,5-0,9

forged, blunt 0,9 0,9 0,9 0,9

molten 0,35 0,4-0,6
Iron, casted non oxidized 0,35 0,3 0,25 0,2

oxidized 0,9 0,7-0,9 0,65-0,95 0,6-0,95

Material

typical Emissivity

Spectral response

Appendix A – Emissivity Table Metals

-46 -

1,0 µm 1,6 µm 5,1 µm 8-14 µm

Lead polished 0,35 0,05-0,2 0,05-0,2 0,05-0,1

roughened 0,65 0,6 0,4 0,4

oxidized 0,3-0,7 0,2-0,7 0,2-0,6
Magnesium 0,3-0,8 0,05-0,3 0,03-0,15 0,02-0,1
Mercury 0,05-0,15 0,05-0,15 0,05-0,15
Molybdenum non oxidized 0,25-0,35 0,1-0,3 0,1-0,15 0,1

oxidized 0,5-0,9 0,4-0,9 0,3-0,7 0,2-0,6
Monel (Ni-Cu) 0,3 0,2-0,6 0,1-0,5 0,1-0,14
Nickel electrolytic 0,2-0,4 0,1-0,3 0,1-0,15 0,05-0,15

oxidized 0,8-0,9 0,4-0,7 0,3-0,6 0,2-0,5
Platinum black 0,95 0,9 0,9
Silver 0,04 0,02 0,02 0,02
Steel polished plate 0,35 0,25 0,1 0,1

rustless 0,35 0,2-0,9 0,15-0,8 0,1-0,8

heavy plate 0,5-0,7 0,4-0,6

cold-rolled 0,8-0,9 0,8-0,9 0,8-0,9 0,7-0,9

oxidized 0,8-0,9 0,8-0,9 0,7-0,9 0,7-0,9
Tin non oxidized 0,25 0,1-0,3 0,05 0,05
Titanium polished 0,5-0,75 0,3-0,5 0,1-0,3 0,05-0,2

oxidized 0,6-0,8 0,5-0,7 0,5-0,6
Wolfram polished 0,35-0,4 0,1-0,3 0,05-0,25 0,03-0,1
Zinc polished 0,5 0,05 0,03 0,02

oxidized 0,6 0,15 0,1 0,1

Spectral response

Material

typical Emissivity

-Appendix B – Emissivity Table Non Metals 47-

1,0 µm 2,2 µm 5,1 µm 8-14 µm

Asbestos 0,9 0,8 0,9 0,95
Asphalt 0,95 0,95
Basalt 0,7 0,7
Carbon non oxidized 0,8-0,9 0,8-0,9 0,8-0,9

graphite 0,8-0,9 0,7-0,9 0,7-0,8
Carborundum 0,95 0,9 0,9
Ceramic 0,4 0,8-0,95 0,8-0,95 0,95
Concrete 0,65 0,9 0,9 0,95
Glass plate 0,2 0,98 0,85

melt 0,4-0,9 0,9
Grit 0,95 0,95
Gypsum 0,4-0,97 0,8-0,95
Ice 0,98
Limestone 0,4-0,98 0,98
Paint non alkaline 0,9-0,95
Paper any color 0,95 0,95
Plastic >50 µm non transparent 0,95 0,95
Rubber 0,9 0,95
Sand 0,9 0,9
Snow 0,9
Soil 0,9-0,98
Textiles 0,95 0,95
Water 0,93

Wood natural 0,9-0,95 0,9-0,95

Material

typical Emissivity

Spectral response

Appendix B – Emissivity Table Non Metals

-48 -

Appendix C – Smart Averaging

The average function is generally used to smoothen the output signal. With the adjustable parameter time
this function can be optimal adjusted to the respective application. One disadvantage of the average function
is that fast temperature peaks which are caused by dynamic events are subjected to the same averaging
time. Therefore those peaks can only be seen with a delay on the signal output.
The function Smart Averaging eliminates this disadvantage by passing those fast events without averaging
directly through to the signal output.

Signal graph with Smart Averaging function Signal graph without Smart Averaging function

-Appendix D - Declaration of Conformity 49-

Appendix D - Declaration of Conformity

optris CSlaser-MA-E2018-12-A