Optris CS LT Operating Manual

optris

®

CS

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 notes ............................................................................................................................................ 7

1.1 Intended use ....................................................................................................................................... 7

1.2 Warranty ............................................................................................................................................. 8

1.3 Scope of delivery ................................................................................................................................ 8

1.4 Maintenance ....................................................................................................................................... 9

2 Technical Data ........................................................................................................................................ 10

2.1 Default settings ................................................................................................................................. 10

2.2 General specifications ...................................................................................................................... 13

2.3 Electrical specifications ..................................................................................................................... 14

2.4 Measurement specifications ............................................................................................................. 16

2.5 Optical charts .................................................................................................................................... 17

-4 -

2.6 Close focus optics ............................................................................................................................. 19

2.7 LED-Functions .................................................................................................................................. 20

2.7.1 Automatic aiming support ......................................................................................................... 20

2.7.2 Self-diagnostic .......................................................................................................................... 21

2.7.3 Temperature code indication .................................................................................................... 22

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

3.1 Mechanical Installation ..................................................................................................................... 24

3.1.1 Mounting accessories ............................................................................................................... 25

3.1.2 Air purge collar .......................................................................................................................... 26

3.1.3 Other accessories ..................................................................................................................... 28

3.1.4 Tilt assembly ............................................................................................................................. 29

3.2 Electrical Installation ......................................................................................................................... 30

3.2.1 Digital communication ............................................................................................................... 32

-Table of contents 5-

3.2.2 Open collector output ................................................................................................................ 33

3.2.3 Direct connection to a RS232 on the computer ........................................................................ 34

4 Schematic circuit diagrams for maintenance applications ................................................................ 35

5 Software CompactConnect .................................................................................................................... 38

5.1 Installation ......................................................................................................................................... 38

5.2 Communication settings ................................................................................................................... 40

5.2.1 Serial Interface .......................................................................................................................... 40

5.2.2 Protocol ..................................................................................................................................... 40

6 Digital command set ............................................................................................................................... 41

7 Basics of Infrared Thermometry ........................................................................................................... 42

8 Emissivity ................................................................................................................................................ 43

8.1 Definition ........................................................................................................................................... 43

8.2 Determination of unknown emissivity ............................................................................................... 44

8.3 Characteristic emissivity ................................................................................................................... 45

-6 -

Appendix A – Table of emissivity for metals ............................................................................................... 46

Appendix B - Table of emissivity for non-metals ........................................................................................ 47

Appendix C – Direct connection to a RS232 interface ................................................................................ 48

Appendix D – Smart Averaging ..................................................................................................................... 50

Appendix E – Declaration of Conformity ...................................................................................................... 51

-General notes 7-

The CS 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 notes

1.1 Intended use

Thank you for choosing the optris® CS infrared thermometer.
The sensors of the optris CS series are non-contact infrared temperature sensors. They calculate the surface
temperature based on the emitted infrared energy of objects [►7 Basics of Infrared Thermometry]

-8 -

1.2 Warranty

Each single product passes through a quality process. Nevertheless, if failures occur 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 non­intended 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 delivery

 CS incl. connection cable
 Two mounting nuts
 Quick start guide

-General notes 9-

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

1.4 Maintenance

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).

-10 -

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

The default settings can be changed with the optional USB kit (USB adapter cable + software). If
the unit is supplied together with the USB kit the output is already preset to digital
communication (bidirectional).

Emissivity

0.950

Transmission

1.000

Average time

0.3 s

Smart averaging

active

Smart averaging hysteresis

2 °C

Ambient temperature source

internal (head)

Status-LED function

Self-diagnostic

2 Technical Data

2.1 Default settings

At time of delivery the unit has the following pre-settings:

-Technical Data 11-

Input (IN/ OUT/ green)

inactive

Output (OUT/ yellow)

mV output

Temperature range

0...350 °C

Output voltage

0...3.5 V

Thermocouple output

Inactive

Vcc adjust

inactive

Signal processing

Hold mode: off

Calibration

Gain 1.000/ Offset 0.0

Failsafe

Inactive

OUT

At 3-state output the following settings are default:

Pre-alarm difference: 2 °C

No alarm level: 8 V

Pre-alarm level: 5 V

Alarm level: 0 V

Service voltage: 10 V

For a usage of the CS for online maintenance applications (in electrical cabinets e.g.) the following
recommend settings are already included in the factory default setting (but not active):

-12 -

IN/ OUT

At Alarm output (open collector) the following settings are default:

Mode: normally closed

Temp code output: activated (for values above alarm level)

Range settings: 0 °C = 0 %/ 100 °C = 100 %

Vcc adjust

If activated the following settings are default:

Output voltage range: 0-10 V

Difference mode: activated

Alarm level Alarm value (IN/ OUT pin) Vcc

1 40 °C 11 V
2 45 °C 12 V
3 50 °C 13 V
4 55 °C 14 V
5 60 °C 15 V
6 65 °C 16 V
7 70 °C 17 V
8 75 °C 18 V
9 80 °C 19 V

10 85 °C 20 V

-Technical Data 13-

Environmental rating

IP63

Ambient temperature

-20...80 °C

Storage temperature

-40...85 °C

Relative humidity

10...95 %, non-condensing

Material

Stainless steel

Dimensions

85 mm, M12x1

Weight

58 g

Cable length

1 m (Standard), 3 m, 8 m, 15 m

Cable diameter

4.3 mm

Vibration

IEC 60068-2-6 (sinus shape), IEC 60068-2-64 (broad band noise)

Shock

IEC 60068-2-27 (25G and 50G)

2.2 General specifications

-14 -

Used Pin

Function

OUT

IN/ OUT x

Analog

0-5 V 1) or 0-10 V 2)/ scalable

x

Alarm

output voltage adjustable; N/O or N/C

x

Alarm

3-state alarm output (three voltage level for no alarm, pre-alarm, alarm)

x

Analog

programmable open collector output (NPN type) [0-30 V DC/ 50 mA] 4)

x

Temp. Code

Temp. Code Output (open collector (NPN type)) [0-30 V DC/ 50 mA]

4)

x

Input

programmable functions:

 external emissivity adjustment
 ambient temperature compensation
 triggered signal output and peak hold function

5)

x

x

Serial digital 3)

uni- (burst mode) or bidirectional

OUT t/c K

Analog

Thermocouple output type K; alternatively selectable to the mV output (software necessary)

Status LED

green LED with programmable functions:

 alarm indication (threshold independent from alarm outputs)
 automatic aiming support
 self-diagnostics
 temperature code indication

2.3 Electrical specifications

-Technical Data 15-

Vcc adjust mode

10 adjustable emissivity and alarm values by variation of supply voltage/ Service mode for analog output

Output impedances

min. 10 kΩ load impedance

Current draw

10 mA

Power supply

5...30 VDC 6)

Power supply [white]
Analog output/ TxD (5 V)/ Alarm output [yellow]
Analog input/ RxD (5 V)/ Open collector output [green]
Ground () [brown]
Thermocouple output type K (+) [green] 1)
Thermocouple output type K (-) [white] 1)
Shield [black]

1)

0...4.6 V at supply voltage 5 VDC; also valid for alarm output

2)

only at supply voltage ≥ 11 V

3)

inverted RS232, TTL, 9.6 kBaud

4)

loadable up to 500 mA if the mV output is not used

5)

High level: > 0.8 V/ Low level: < 0.8 V

6)

CS either via USB or external power supply and not simultaneously

1)

The t/c wires are indicated with an additional cable marker to avoid wrong connections due to the identical cable colors of other wires

(white, green).

-16 -

Temperature range

-40...1030 °C (scalable via Software)

Spectral range

8...14 µm

Optical resolution

15:1

CF-lens (optional)

0.8 mm@ 10 mm

Accuracy

1) 2)

±1.5 °C or ±1.5 % of reading (whichever is greater)

Repeatability 1)

±0.75 °C or ±0.75 % of reading (whichever is greater)

Temperature coefficient 3)

±0.05 K/ K or ±0.05 %/ K (whichever is greater)

Temperature resolution (NETD) 4)

0.1 K

Response time

25 ms (95 % Signal/ adjustable to 999 s via Software)

Warm-up time

10 min

Emissivity/ Gain

0,100...1,100 (adjustable via 0-10 VDC input or software)

Transmissivity

0,100...1,000 (adjustable via software)

Interface (optional)

USB programming interface

Signal processing

Average, Peak hold, Valley hold, Advanced peak hold with threshold and
hysteresis, Triggered signal output, Triggered peak hold function (adjustable via
software)

2.4 Measurement specifications

-Technical Data 17-

Software

optional (CompactConnect)

 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.

1)

at ambient temperature 235 °C and object temperatures >0 °C

2)

Accuracy for thermocouple output: ±2.5°C or ±1%

3)

for ambient temperatures <18 °C and >28 °C

4)

at time constant ≥100 ms with smart averaging and an object temperature of 25 °C

2.5 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 sensor housing/ CF-lens holder/ air purge.
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.

-18 -

Figure 1: Optical chart CS (15:1)

Figure 2: Optical chart CS (15:1) with CF-lens (0.8 mm@ 10 mm)

-Technical Data 19-

 If the CF-lens is used, the transmission has to be set to 0.78. To change this value the

optional USB-Kit (including software) is necessary.

 The assigned transmission (average value) is a characteristic value which may has a certain

scattering. If required the transmission has to be determined.

Figure 3: CF-lens [Order-No.: ACCTCF]

Figure 4: Laminar air purge with integrated CF-lens
[Order-No.: ACCTAPLCF]

2.6 Close focus optics

The optional CF-lens allows the measurement of small objects. The CF optics can also be combined with a
laminar air purge

-20 -

LED Alarm

LED lights up if the object temperature exceeds or deceeds an alarm threshold

Automatic aiming support

Sighting feature for an accurate aiming of the CS to hot or cold objects

Self-diagnostic

LED is indicating different states of the sensor

Temperature Code indication

Indication of the object temperature via the LED

Off

LED deactivated

2.7 LED-Functions

The green LED can be programmed for the following functions. For the programming the USB adapter
cable incl. software (option) is necessary. The factory default setting for the LED is self-diagnostic.

2.7.1 Automatic aiming support

The automatic aiming support helps to adjust the unit to an object which has a temperature different to the
background. If this function is activated via software the sensor is looking for the highest object temperature;
means the threshold value for activating the LED will be automatically tuned.

This works also if the sensor is aimed at a new object (with probably colder temperature). After expiration of
a certain reset time (default setting: 10 s) the sensor will adjust the threshold level for activation of the LED
new.

-Technical Data 21-

At a supply voltage (Vcc) ≥ 12 V it takes about 5 minutes until the sensor works in a stable

mode. Therefore, after switching on the unit, the LED will show a not stable state for up to
5 minutes.

If activated, the LED will show one out of five possible states of
the sensor:

Status LED mode

Normal intermittent off - - - ­Sensor overheated fast flash - - - - - - - - - - - - ­Out of measuring range double flash -- -- -- -- -- -- -­Not stable intermittent on ––– ––– ––– –––
Alarm fault always on –––––––––––––––

2.7.2 Self-diagnostic

With this function the current status of the sensor will be indicated by different flash modes of the LED.

Figure 5: Sensor status

-22 -

Sensor overheated

The internal temperature probes have detected an invalid high internal temperature of the CS.

Out of meas. range

The object temperature is out of measuring range.

Not stable

The internal temperature probes have detected an unequally internal temperature of the CS.

Alarm fault

Current through the switching transistor of the open-collector output is too high.

Long flashing  first digit: xx

Short flashing  second digit: xx

10-times long flashing  first digit=0: 0x

10-times short flashing  second digit=0: x0

2.7.3 Temperature code indication

With this function the current measured object temperature will be indicated as percentage value by long and
short flashing of the LED. At a range setting of 0-100 °C  0-100 % the LED flashing indicates the
temperature in °C.

-Technical Data 23-

Examples
87 °C 8-times long flashing indicates 87

and afterwards 7-times short flashing indicates 87
31 °C 3-times long flashing indicates 31
and afterwards 1-time short flashing indicates 31
8 °C 10-times long flashing indicates 08
and afterwards 8-times short flashing indicates 08
20 °C 2-times long flashing indicates 20

and afterwards 10-times short flashing indicates 20

-24 -

3 Installation

3.1 Mechanical Installation

The CS is equipped with a metric M12x1 thread and can be installed either directly via the sensor thread or
with the help of the both hex nuts (standard) to the mounting bracket available.

Figure 6: Dimensions CS

For an exact aiming of the sensor to an object the LED function ►2.7.1 Automatic aiming support can be
used.

-Installation 25-

The Mounting fork can be combined with the Mounting bracket [Order No.: ACCTFB] using
the M12x1 thread.

Figure 7: Mounting bracket, adjustable in one axis
[Order No.: ACCTFB]

Figure 8: Mounting bolt with M12x1 thread, adjustable in
one axis [Order No.: ACCTMB]

3.1.1 Mounting accessories

-26 -

Figure 9: Mounting fork with M12x1 thread, adjustable in
2 axes [Order No.: ACCTMG]

Figure 10: Mounting bracket, adjustable in two axes
[Order No.: ACCTAB]

 Use oil-free, technically clean air only.
 The needed amount of air (approx. 2...10 l/ min.) depends on the application and the

installation conditions on-site.

3.1.2 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.

-Installation 27-

Figure 11: Standard air purge collar; fits to the mounting
bracket; hose connection: 3x5 mm [Order No.: ACCSAP]

Figure 12: Laminar air purge collar – the side air outlet
prevents a cooling down of the object in short distances;
hose connection: 3x5 mm [Order No.: ACCTAPL]

Figure 13: A combination of the laminar air purge collar with the bottom section of the mounting fork allows an
adjustment in two axes. [Order No.: ACCTAPL+ACCTMG]

-28 -

If the protective window is used, the transmission has to be set to 0.83. To change this value the
optional USB-Kit (including CompactConnect software) is necessary.

Figure 14: Right angle mirror enables measurement with
90° angle, for sensing heads with optical resolution ≥10:1
[Order No.: ACCTRAM]

Figure 15: Protective window same mechanical size as
CF lens [Order No.: ACCTPW]

3.1.3 Other accessories

-Installation 29-

Figure 16: USB adapter cable incl. terminal block and software CD [Order No.: ACCSUSBK]

3.1.4 Tilt assembly

With this mounting accessory a fine adjustment of the CS with an off-axis angle +/- 6.5° is possible.

Figure 17: Tilt assembly [Order No.: ACCTTAS]

-30 -

Use a separate, stabilized power supply unit with an output voltage in the range of 5–30 VDC
which can supply 100 mA. The residual ripple should be max 200 mV.

Note: CS either via USB or external power supply and not simultaneously!

 Use shielded cables only. The sensor shield has to be grounded.
 The shield [black] on the CS is not connected to GND [brown].In any case it is necessary to

connect the shield to ground or GND (whichever works best)!

 When using the thermocouple and an external power supply, there must be a connection

between ground and shield.

The output impedance must be ≥ 10 Ω.

3.2 Electrical Installation

Analog device (mV-output at OUT pin)

-Installation 31-

The output impedance must be ≥ 20 Ω.

Figure 18: Analog device (mV output at OUT pin)

Analog device (Thermocouple typ K at OUT t/c K pins)

Figure 19: Analog device (Thermocouple typ K at OUT t/c K pins)

-32 ­You can choose between an mV output (0-5 or 0-10 V; scalable via software) and a thermocouple output

type K. Therefor the optional software is needed. The factory default setting is mV output.
►2.1 Default settings

The thermocouple output supplies a voltage according to the t/c characteristic curve type K. If you want to
extend this output you have to use a suitable thermocouple extension cable (NiCr-Ni).

3.2.1 Digital communication

For a digital communication the optional USB programming kit is required.

1. Connect each wire of the USB adapter cable with the same colored wire of the sensor cable by using
the terminal block. Press with a screw driver as shown in the picture to lose a contact.

Figure 20: Connection USB cable

-Installation 33-

In case of long lines there is a drop voltage at the ground wire and the mV-output is distorted.
Because of that the brown wire can be used as ground supply and the t/c- wire (type K) as
measuring ground.

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)

Figure 21: Digital communication

3.2.2 Open collector output

-34 -

Figure 22: Open collector output as additional alarm output

The open collector output is an additional alarm output on the CS and can control an external relay e.g. In
addition the analogue output can be used simultaneously.

3.2.3 Direct connection to a RS232 on the computer

For a bidirectional RS232 connection of the sensor the following interface circuit can be used: MAX3381E
(manufacturer: Maxim) ► Appendix C – Direct connection to a RS232 interface:

-Schematic circuit diagrams for maintenance applications 35-

4 Schematic circuit diagrams for maintenance applications

Figure 23: Open collector output for direct 24 V DC signal lamp control

-36 -

Figure 24: Common power supply voltage change to adjust simultaneously alarm levels and emissivity values
[Vcc adjust mode]

-Schematic circuit diagrams for maintenance applications 37-

Figure 25: Simple common alarm and pre-alarm generation

-38 -

Minimum system requirements:

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

 A detailed description is provided in the software manual on the software CD.
 The software only supports USB cables ordered directly from Optris.

5 Software CompactConnect

5.1 Installation

1. Insert the installation CD into the according drive on your computer. If the autorun option is
activated the installation wizard will start automatically.

2. Otherwise start setup.exe from the CD-ROM. Follow the instructions of the wizard until the
installation is finished.

-Software CompactConnect 39-

Figure 26: Software CompactConnect

Main functions:

 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

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

Start\Programs\CompactConnect

To uninstall the software from your system use the uninstall icon in the start menu.

-40 -

For further information see protocol and command description on the software CD
CompactConnect in the directory: \Commands.

Baud rate:

9,6...115,2 kBaud (adjustable on the unit or via software)

Data bits:

8

Parity:

none

Stop bits:

1

Flow control

off

5.2 Communication settings

5.2.1 Serial Interface

5.2.2 Protocol

All sensors of the CTlaser series are using a binary protocol. Alternatively they can be switched to an ASCII
protocol. To get a fast communication the protocol has no additional overhead with CR, LR or ACK bytes.

-Digital command set 41-

Commands CS/ CSmicro/ CX

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

129 0x81 binary SET DAC mV/ mA byte1 byte1 byte 1= mV (mA) x 10 (e.g. 4mA = 4 x 10=40) °C
130 0x82 binary RESET of DAC mV/ mA output
132 0x84 binary SET Emissivity byte1 byte2 byte1 byte2 = (byte1 x 256 + byte2) / 1000

Temperature calculation at CSmicro 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 CSmicro 2Whs)

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

Burst string Example Complete burst string Conversion to decimal value

2 synchronisation bytes: AAAA ------ -----­2 bytes for each output value (HI LO) 03B8 AAAA 03B8

process temp [°C] = (Hex  Dec(03B8)-1000)/10 = -4,8

After switch on a continuous serial signal will be created. The burst string can be configured with the software.

Burstmode (unidirectional)

6 Digital command set

-42 -

7 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 (►8 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-

8 Emissivity

8.1 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.

-44 -

8.2 Determination of unknown emissivity

► 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 –

Order No.: ACLSED) onto the measuring object, which covers it completely. Set the emissivity to 0.95
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.

-Emissivity 45-

8.3 Characteristic emissivity

In case none of the methods mentioned above help to determine the emissivity you may use the emissivity
table ► Appendix A and Appendix B. 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)

-46 -

typical

Emissivity

typical

Emissivity

Aluminium non oxidized 0,02-0,1 Lead roughened 0,4

polished 0,02-0,1 oxidized 0,2-0,6
roughened 0,1-0,3 Magnesium 0,02-0,1
oxidized 0,2-0,4 Mercury 0,05-0,15

Brass polished 0,01-0,05 Molybdenum non oxidized 0,1

roughened 0,3 oxidized 0,2-0,6
oxidized 0,5 Monel (Ni-Cu) 0,1-0,14

Copper polished 0,03 Nickel electrolytic 0,05-0,15

roughened 0,05-0,1 oxidized 0,2-0,5

oxidized 0,4-0,8 Platinum black 0,9
Chrome 0,02-0,2 Silver 0,02
Gold 0,01-0,1 Steel polished plate 0,1
Haynes alloy 0,3-0,8 rustless 0,1-0,8
Inconel electro polished 0,15 heavy plate 0,4-0,6

sandblast 0,3-0,6 cold-rolled 0,7-0,9

oxidized 0,7-0,95 oxidized 0,7-0,9
Iron non oxidized 0,05-0,2 Tin non oxidized 0,05

rusted 0,5-0,7 Titanium polished 0,05-0,2

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

forged, blunt 0,9 Wolfram polished 0,03-0,1
Iron, casted non oxidized 0,2 Zinc polished 0,02

oxidized 0,6-0,95 oxidized 0,1

Lead polished 0,05-0,1

Material

Material

Appendix A – Table of emissivity for metals

-Appendix B - Table of emissivity for 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 - Table of emissivity for non-metals

-48 -

Appendix C – Direct connection to a RS232 interface

For a bidirectional RS232 connection of the sensor we recommend the interface circuit from Maxim, e.g.
MAX3381E.

-Appendix C – Direct connection to a RS232 interface 49-

Model

CSv1

CSv2

UART voltage (RxD)

5 V

3,3 V

UART voltage (TxD)

5 V

3,3 V

CS connections:

TxD (yellow) an T1IN

RxD (green) an R1OUT

GND (brown) an GND

PC connections:

connect T1OUT with RxD (PC)

connect R1IN with TxD (PC)

Previous sensor versions:
CSv1 CS/ version 1 (→ 12/2010)

-50 -

Appendix D – 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 E – Declaration of Conformity 51-

Appendix E – Declaration of Conformity

optris CS-MA-E2018-11-A