Testo Instruments 875-KIT User manual

testo 875i · Thermal imager

Instruction manual

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1 Contents

1 Contents

1 Contents ................................................................................................... 3

2 Safety and the environment .................................................................... 4

2.1. About this document ........................................................................ 4

2.2. Ensure safety ................................................................................... 5

2.3. Protecting the environment .............................................................. 6

3 Specifications .......................................................................................... 7

3.1. Use .................................................................................................. 7

3.2. Technical data ................................................................................. 8

4 Product description ............................................................................... 13

4.1. Overview........................................................................................ 13

4.2. Basic properties ............................................................................. 14

5 First steps .............................................................................................. 16

5.1. Commissioning .............................................................................. 16

5.2. Getting to know the product ........................................................... 18

6 Using the product .................................................................................. 25

6.1. Menu functions .............................................................................. 25

6.1.1. Measuring functions ....................................................................................... 25

6.1.2. Image gallery ................................................................................................. 28

6.1.3. Scale... ........................................................................................................... 29

6.1.4. Display... ........................................................................................................ 30

6.1.5. Emissivity... .................................................................................................... 30

6.1.6. Palette ........................................................................................................... 33

6.1.7. Configuration ................................................................................................. 33

6.2. Measuring ...................................................................................... 38

7 Maintaining the product ........................................................................ 41

8 Tips and assistance ............................................................................... 43

8.1. Questions and answers ................................................................. 43

8.2. Accessories and spare parts ......................................................... 44

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2 Safety and the environment

2 Safety and the environment

2.1. About this document

Use

> Please read this documentation through carefully and

familiarize yourself with the product before putting it to use. Pay
particular attention to the safety instructions and warning advice
in order to prevent injuries and damage to the products.

> Keep this document to hand so that you can refer to it when

necessary.

> Hand this documentation on to any subsequent users of the

product.

Warnings

Always pay attention to information that is marked by the following
warnings with warning pictograms. Implement the specified
precautionary measures.

Representation Explanation

WARNING

NOTICE

Symbols and writing standards
Represen-

Indicates potential serious injuries

indicates circumstances that may lead to
damage to the products

Explanation

tation

Note: Basic or further information.

1. ...

Action: more steps, the sequence must be followed.

2. ...

> ... Action: a step or an optional step.

- ... Result of an action.

Menu Elements of the instrument, the instrument displays

or the program interface.

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2 Safety and the environment

Represen-

Explanation

tation

[OK] Control keys of the instrument or buttons of the

program interface.

... | ... Functions/paths within a menu.

2.2. Ensure safety

“...” Example entries

> Only operate the product properly, for its intended purpose and

within the parameters specified in the technical data. Do not
use any force.

> Do not operate the instrument if there are signs of damage at

the housing, mains unit or feed lines.

The thermal imager must not be directed at the sun or other
sources of intense radiation (e.g. objects with temperatures greater
than 500 °C, 800 °C while using the high-temperature filter) during
operation. This may lead to serious damage to the detector. The
manufacturer accepts no warranty for this type of damage to the
microbolometer detector.

> The objects to be measured or the measurement environment

may also pose risks: Note the safety regulations valid in your
area when performing the measurements.

> Do not store the product together with solvents. Do not use any

desiccants.

> Carry out only the maintenance and repair work on this

instrument that is described in the documentation. Follow the
prescribed steps exactly. Use only original spare parts from
Testo.

> Improper use of rechargeable batteries can lead to destruction

or injuries by means of current surges, fire or escaping
chemicals. The following instructions must be observed to avoid
such hazards:

• Only use in accordance with the directions in the instruction
manual.

• Do not short, take apart or modify.

• Do not expose to heavy impacts, water, fire or temperatures
above 60 °C.

• Do not store in the proximity of metal objects.

• Do not use leaky or damaged rechargeable batteries. In the
event of contact with battery acid: Thoroughly wash affected
area with water and consult a doctor, if necessary.

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2 Safety and the environment

• Only charge in the instrument or the recommended charging

station.

• Immediately stop the charging process if this is not

completed in the given time.

• In the event of improper function or signs of overheating,

immediately remove the rechargeable battery from the
measuring instrument/charging station. Caution:
Rechargeable battery may be hot!

• During longer breaks, remove the battery from the

2.3. Protecting the environment

instrument to avoid exhaustive discharge.

> Dispose of faulty rechargeable batteries/spent batteries in

accordance with the valid legal specifications.

> At the end of its useful life, send the product to the separate

collection for electric and electronic devices (observe local
regulations) or return the product to Testo for disposal.

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3 Specifications

3.1. Use

The testo 875i is a handy and robust thermal imager. It opens the
door to contactless determination and illustration of the temperature
distribution on surfaces for you.

Typical areas of application are:

• Building inspection (heating, ventilation and air conditioning
trade, company technicians, engineering offices, experts):
Energy evaluation of buildings

• Preventative maintenance (servicing): Mechanical and electrical
inspection of systems and machines

• Production monitoring (quality assurance): Monitoring
production processes

The testo 875i is available in several versions, which are tailored to
various usage requirements:

• testo 875-1i: High-quality wide-angle lens 32° x 23, detector
160 x 120, NETD < 50 mK, 2 GB SD card for approx. 1000
images, minimum focus distance 10 cm, integrated digital
camera

• testo 875-2i: High-quality wide-angle lens 32° x 23°, detector
160 x 120, NETD < 50 mK, 2 GB SD card for approx. 1000
images, minimum focus distance 10 cm, integrated digital
camera with power LEDs for illumination, isotherm, min./max.
on area, audio comments, display of surface moisture
distribution (real-time display with optional radio humidity
probe), high-temperature filter (optional)

3 Specifications

Export control

Thermal imagers may be subject to the export restrictions of the
European Union.

The testo 875i with 33 Hz in particular can only be exported to
countries outside of the European Union with an export permit from
the authorities.

Please observe the national regulations for export control when
exporting.

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3 Specifications

3.2. Technical data

Infrared image output
Characteristic Values

Field of vision/min.
focusing distance

Standard lens: 32° x 23°/0.1 m (0.33 ft)
Telephoto lens (testo 875-2i only, optional):

9° x 7° / 0.5 m (1.64 ft)

Thermal sensitivity

<50 mK at 30 °C (86 °F)

(NETD)

Geometric resolution

Standard lens: 3.3 mrad
Telephoto lens: 1 mrad

Refresh rate

33 Hz within EU and countries approved for
export, else 9 Hz

Focus Manual

Detector type FPA 160 x 120 pixels, a.Si

Spectral range 8 - 14 μm

Visual image output
Characteristic Values

Field of vision/min.

33° x 25°/0.4 m (1.31 ft)

focusing distance

Image size 640 x 480 pixels

Refresh rate 8 to 15 Hz

Image presentation
Characteristic Values

Image display 3.5" LCD with 320 x 240 pixels

Display options

Infrared image/real image/infrared and real
image

Video stream 25 Hz

Colour palettes 10 options

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3 Specifications

Measuring
Characteristic Values

Temperature range
(can be changed)

Measuring range 1:

-20 - 100 °C (-4 - 212 °F)
Measuring range 2:

0 - 350 °C (32 - 662 °F)
Measuring range 3 (optional, testo 875-2i

only):
350 - 550 °C (662 - 1022 °F)

Accuracy

With measuring range 1 activated, for
readings within the range of -20 - 100 °C
(-4 - 212 °F):
±2 °C (±3.6 °F)

With measuring range 2 activated, for
readings within the range of 0 - 350 °C
(32 - 662 °F):
±2 °C (±3.6 °F) or ±2 % of reading
(whichever is the greater)

With measuring range 3 activated (optional,
testo 875-2i only), for readings within the
range of 350 - 550 °C (662 - 1022 °F):
±3 % of reading

Reproducibility

±1 °C (±1.8 °F) or ±1 % (whichever is the
greater)

Measuring point
minimum diameter

On-time (time to

Standard lens: 10 mm at 1 m
Telephoto lens: 3 mm at 1 m

30 s

image)

Humidity and
ambient temperature

0…100%rF,

-20…70°C (-4…158°F)
measurement with
radio probe (optional,
only testo 875-2i)

Accuracy of radio
probe (optional, only

±2%rF,
±0,5°C (0,9°F)

testo 875-2i)

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3 Specifications

Characteristic Values

Measuring functions

Standard measurement (1-point), 2-point
measurement, Cold-/Hotspot, solar (manual
entry of the radiation intensity)

Also with testo 875-2i: isotherm, min./max.
on area, Display of humidity image via
manual entry of the ambient humidity /
temperature (real-time display with optional
radio humidity probe)

Compensation for

manual

reflected temperature

Setting emissivity 0.01…1.00

Image storage
Characteristic Values

File format .bmt

Export options in .bmp, .jpg, .csv

Removable memory SD card

Memory capacity

Scope of delivery: 2 GB (approx. 1000
images)

Lens
Characteristic Values

Standard lens 32° x 23°

Telephoto lens

9° x 7°
(optional,
testo 875-2i only)

Aperture 0.84

w

Laser measuring spot marking

Not available in USA, Japan, China.

Characteristic Values

Classification of the

635 nm, Class 2

laser

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3 Specifications

Audio functions (testo 875i-2 only)
Characteristic Values

Sound

via headset (included in delivery)

recording/playback

Recording period max. 30 s per image

Power supply
Characteristic Values

Battery type

Fast-charging, Li-ion battery can be
changed on-site

Operating time approx. 4 h at 20 - 30 °C (68 - 86 °F)

Charging option In instrument/in charging station (optional)

Mains operation Yes, with mains unit 0554 8808

Mains unit output

5 V/4 A

voltage

Ambient conditions
Characteristic Values

Operating

-15 - 40 °C (5 - 113 °F)

temperature

Storage

-30 - 60 °C (-22 - 140 °F)

temperature

Air humidity 20 - 80 %RH, not condensing

Physical features
Characteristic Values

Weight 900 g (including battery)

Dimensions 152 x 108 x 262 mm (5.98 x 4.17 x 10.31")

Tripod mounting Yes, with adapter (included in delivery)

Housing ABS

Enclosure rating of
the housing

IP54 (Interface terminals closed, battery
connected, lens mounted, softcase
mounted)

Vibration max. 2 G

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3 Specifications

Standards, tests, warranty
Characteristic Values

EU Directive 2004/108/EC

Vibration IEC 60068-2-6

Warranty

2 years, warranty conditions

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4 Product description

4.1. Overview

4 Product description

Product components

1 Display.
2 Control keys:

Key Functions

[]
[OK] and Joystick

Switch the imager on/off.

• Press [OK]:

Open menu, confirm selection/setting.

• Move [OK] up/down/right/left = Joystick
function:
Select functions, navigate

[Esc]

Left/right ["xy"]
quick select button

Cancel action.

Call up a function. The function assigned to
the quick select button at any one time is
shown in the display.

3 Instrument rechargeable battery lock release button.

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4 Product description

4 Metric thread: For fastening the included tripod adapter.

Do not use desktop tripods, danger of tilting!

5 Right interface terminal: Radio module compartment.
6 2 LEDs: For illumination for the visual image (testo 875-2i only).
7 Digital camera lens: For recording visual images
8 Laser (not available in all countries): For aiming at the

measuring field.

Laser radiation. Do not look into the beam.
CLASS 2 LASER

9 Infrared camera lens: For recording thermography images.

Exchangeable lens (testo 875-2i only).

10 Rotating ring Manual focusing: For manual focusing.
11 Lens lock ring
12 [Trigger]: For recording (freezing/saving) images.
13 Left interface terminal: Memory card slot. Headset slot. USB

interface. Mains socket, for connecting the included mains unit.
Buffer battery slot.

14 Status LED: off (no mains unit connected), flashes (mains unit

connected and rechargeable battery charging), lights up (mains

4.2. Basic properties

unit connected and battery charging process completed).

14

Voltage supply

The power is supplied to the instrument via an exchangeable
rechargeable battery or via the included mains unit.

With an attached mains unit, the power is supplied automatically
via the mains unit and the instrument's rechargeable battery is
charged (only at ambient temperatures from 0 to 45 °C).

Charging the battery is also possible using a desktop charging
station (accessory).

The instrument is equipped with a buffer battery (type CR 1632) to
maintain the system data during an interruption in the power
supply (e.g. when the battery is changed).

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File formats and file names

The images are saved according to the following pattern:
XX_YYYYY.ZZZ

XX: IV for IR/humidity image with relevant real image, VI for real
image.

YYYYY: 5-digit consecutive number
ZZZ (file extension): BMT for IR/humidity image with relevant real

image, BMP for real image.

4 Product description

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5 First steps

5 First steps

5.1. Commissioning

Connect rechargeable battery

The imager is delivered with a rechargeable battery that is inserted
in the rechargeable battery slot but not connected.

> Push the battery all the way into the rechargeable battery slot

until this is flush with the bottom of the handle.

-

T
h
e

- The thermal imager starts automatically.

Perform basic settings

> Remove the protective film from the display.

- The start screen appears on the display.

- The Landeseinstellungen (Country settings) dialogue is

opened.

Instrument language (Language) and temperature unit (Unit) can
be set.

1. Move Joystick up/down to select the desired option.

- The selected option has an orange border.

2. Confirm the selection with [OK].

- The selected setting is highlighted orange ( ). The arrows ( )

show that the setting can be changed.

3. Move Joystick up/down to change the setting.

4. Confirm the entry with [OK].

5. Confirm the settings with Übernehmen (Apply).

6. Press [] to switch off the thermal imager.

Initial charging of rechargeable battery

The thermal imager is delivered with a partially charged battery.
Completely charge the battery before use.

> Connect the country-specific adapter required for the existing

mains to the mains unit.

1. Open the cover on the left side of the thermal imager (1).

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5 First steps

2. Connect the mains unit to the mains socket ( ) (2).

3. Connect the mains plug to a mains socket.

- The thermal imager starts automatically.

When charging the rechargeable battery, the imager can
remain switched on or be switched off. This has no effect
on the length of the charging process.

- The charging of the rechargeable battery begins.

- The charge status is indicated on the status LED:

• LED flashes: Charging in process.

• LED lights up: Battery charged, charging process finished.

4. Charge the rechargeable battery completely, then disconnect
the instrument from the mains unit.

- After the initial charging of the battery, the thermal imager is
ready for operation.

Charging the battery is also possible using a desktop charging
station (accessory).

Rechargeable battery care:

• Do not fully exhaust rechargeable batteries.

• Store rechargeable batteries only in charged condition
and at low temperatures, but not below 0°C (best
storage conditions with a charge level of 50-80%, at an
ambient temperature of 10-20°C, recharge completely
before use).

• During longer breaks, you should discharge and
recharge the batteries every 3-4 months. Trickle
charging should not exceed 2 days

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5 First steps

5.2. Getting to know the product

Insert the memory card

1. Open the cover on the left side of the thermal imager.

2. Insert memory card (SD card) into the card slot (SD) (1).

> To remove the memory card: Press on the memory card to

release the lock.

Inserting a radio module (accessory, testo 875-2i only)

Using a radio module (accessory) the instrument can be connected
with a radio humidity probe. The radio module must be connected
before switching on the instrument in order for the instrument to be
identified.

Radio probes may only be used in countries in which
they are permitted (see separate instructions for use of
radio probe).

> Switch off instrument before inserting the radio module.

1. Open the cover on the right side of the thermal imager.

2. Release the lock (1) and open the retaining clip (2).

3. Insert radio module into the module slot (3).

> To remove the radio module: push radio module down slightly

and remove.

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5 First steps

Attaching headset (testo 875-2i only)

1. Open the cover on the left side of the thermal imager.

2. Insert stereo jack of the headset into the headset slot (1).

Mount/remove infrared protection glass

Installation:

1. Attach the protection glass (with black fitting) fastened to the
red mounting ring to the lens and turn the mounting ring
clockwise to the stop.

2. Remove the red mounting ring from the protection glass.

Removal:

1. Attach the red mounting ring to the protection glass.

2. Turn the mounting ring anticlockwise and remove the protection
glass.

After mounting/removing the protection glass, activate or deactivate
the Protection glass option, see Optics..., page 34. If this option is
set incorrectly, the specified measuring accuracy is not ensured.

Mounting/removing high-temperature filter (testo 875-2i only)

Installation:

1. Attach the high-temperature filter (with red fitting) fastened to
the red mounting ring to the lens and turn the mounting ring
clockwise to the stop.

2. Remove the red mounting ring from the high-temperature filter.

Removal:

1. Attach the red mounting ring to the high-temperature filter.

2. Turn the mounting ring anticlockwise and remove the high­temperature filter.

Activate/deactivate the high-temperature measuring range (350.0 -

550.0 °C or 662.0 - 1022 °F), see Measuring range, page 28, after

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5 First steps

mounting or removing the high-temperature filter, otherwise the
specified measuring accuracy is not ensured

Mount tripod adapter

Using the included tripod adapter, the imager can be fastened to
the testo tripod (accessory) or to a commercially available standard
tripod. With the tripod adapter mounted, the battery cannot be
changed!

1. Place the tripod adapter on the lower end of the handle and

screw on using the included Allen key (ISO 2936, size 4).

2. Slide thermal imager into the fastening plate of the testo tripod

and lock or fasten it to the commercially available standard
tripod (screw-type fastening).

Mounting Softcase

The Softcase combines the functions of instrument protection, Sun
Shield and carrying function (strap).

1. Set the Softcase on the imager from above (1) and pull both

sides of the Softcase down around the display (2).

2. Guide Velcro strip through the two plates (3) and close (4).

Changing lens

Only lenses that were adjusted to the respective thermal imager
can be used. The serial number on the lens must match the serial
number of the instrument, see Optics..., page 34.

> Switch instrument off before changing the lens.
> To keep the lens from falling out: Hold the instrument with the

lens pointing up.

1. Turn lens lock ring anticlockwise to the stop (approx. 2 cm).

2. Remove lens.

3. Insert new lens, taking care to align the white markings on the

lens and the instrument with one another.

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5 First steps

4. Turn the lens lock ring clockwise to the stop.

Always store lenses not in use in the container designed for this in
the case.

> Turn the lens ring clockwise to the stop, place the lens in the

container and close it.

The following steps are only relevant for USA:

5. Note or remember the serial number (Serial no.) which is
displayed on the lens.

6. Press [ ].

If you have changed from a wide-angle to a telephoto lens or vice
versa:

- The information No lens/wrong lens appears.
> Press [OK] to confirm the information.

If you have changed between two wide-angle or two telephoto
lenses:

> [OK] | Configuration… | [OK] | Optics… | [OK].

- The dialog Optics opens.

7. Move joystick up/down to select the lens used.

- The lens selected is outlined in orange.

8. Press function key [Apply].

- The information Restart instrument appears.

9. Press [

].

- The instrument switches off.

> To switch on the instrument: Press [ ].

Switch the imager on/off

1. Remove protection cap from the lens.

2. Press [ ].

- The start screen appears on the display. The type designation
of the imager and the firmware version are shown.

- The measurement view is opened after the warm-up period.

- The imager performs an automatic zeroing approx. every 60
sec. This can be recognized by means of a "click". The image is
frozen briefly when this occurs.

> To switch off: Press [

- The display goes out and the imager is switched off.

].

Manually focusing the image

> Turn Rotating ring of the lens until the image is in focus.

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5 First steps

Record (freeze/save) image

1. Press [Trigger].

- The image is frozen (fixed image).
If the image is to be saved, the desired storage location can be set

using the left [Folder] quick select button, see Select the storage
location (folder), page 39.

• Infrared image or infrared/real image is shown: Infrared image

is saved, real image is saved in the same file as an attachment
to the infrared image (even when saving in infrared image
mode)1.

• Real image is shown: Real image is saved.

2. Save image: Press [Trigger] again, or: Press [OK].

or
Discard image: Press [ESC].

Getting to know the quick select buttons

The quick select buttons can be assigned functions that are
required often so that you can call them up directly.

Factory settings:

• Left quick select button: [Scale].

• Right quick select button: [Image type].

WARNING

Eye damage due to laser beam!

> Do not look into the laser beam.
> Do not point the laser beam at people.

1

All saved images are shown in picture-in-picture mode in the gallery.

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5 First steps

Changing assignment of the quick select buttons

1. Move Joystick left or right to open the Configure key function
list for the left or right quick select button.

2. Move Joystick up/down to select the desired function.

Function Description

Image type Change display mode: Infrared image, real

image or infrared/real image.

Laser Switch on laser for homing in on the

measuring surface (hold button down).

Light (testo 875-2i

only)

Switch on/off LEDs for lighting up objects for
the digital camera.

2

3

Palette Change colour palette for the infrared

image.

Emissivity...
Scale...
Adjustment

3. Press [OK] to activate the selected function.

Set emissivity and reflected temperature.

Set scale limits.

Perform manual zero point calibration.

Navigating in the menu

1. Press [OK] button.

- The Menu is opened.

2. Select navigation/function:

• Move Joystick up or down to select the menu item.

• Press [OK] to confirm the selection. Or for menu items that

are marked with an arrow (►): Move Joystick to the right.

• Move Joystick to the left to return to the previous menu

level.

• Press [OK] to select the function.

• Press [ESC] to cancel the process and change to

Measuring Mode.

2

Real image and infrared lens have a different angle of view due to the spacial
separation. The image areas therefore do not correspond completely (parallax
error).

3

Laser and lens have a different angle of view due to the spacial separation.
The laser sighting and the centre of the image thus do not correspond
completely (parallax error).

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5 First steps

- Depending on the selected menu item, press [OK] to perform a

setting or open a submenu/dialogue, see Menu functions, page

25.

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6 Using the product

6.1. Menu functions

6.1.1. Measuring functions

1-point measurement

The 1-point measurement is the standard measuring function. If

this is activated ( ), all available options can be selected via the
quick select buttons.

> [OK] | Measurement | [OK] | 1-point measurement | [OK].
If the 1-point measurement is activated, the crosshairs can be

moved using the Joystick on frozen and saved images to read off
the individual temperatures.

With saved images, the 1-point measurement must be activated
via the menu for the respective opened picture.

2-point measurement

The 2-point measurement has 2 crosshairs with which individual

temperatures can be read off. If this function is activated ( ), the
quick select buttons are fixed with the functions Temperature 1
and Temperature 2.

With frozen images, only the activated crosshairs can be moved.
With saved images, the 2-point measurement must be activated

for the respective opened picture.

1. [OK] | Measurement | [OK] | 2-point measurement | [OK].

2. Select left or right Temperature 1 or Temperature 2 quick

select button to activate one of the two crosshairs.

- The activated crosshairs are shown red.

3. Use the Joystick to move the activated crosshairs in order to

read off the individual temperatures.

6 Using the product

Cold-/Hotspot

Cold-/Hotspot shows the minimum and maximum temperature

point on the display. If Cold-/Hotspot is activated ( ), the quick
select buttons with the Coldspot and Hotspot functions can be
permanently assigned and can no longer be changed.

With frozen images, the crosshairs can be moved and the
min./max. point is visible. The min./max. point is not saved.

With saved images, Cold-/Hotspot must be activated for the
respective opened image.

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6 Using the product

> [OK] | Measurement | Cold-/Hotspot | [OK].
> Select left or right Coldspot or Hotspot quick select button to

Min./Max. on area (testo 875-2i only)

Min./Max. on area shows the minimum and maximum temperature

value within the area selection shown on the display. The area
selection is neither scalable nor adjustable. If Min./Max. on area is

activated ( ), the quick select buttons with the Scale... and

Emissivity... functions can be permanently assigned and can no

longer be changed.
With frozen images, the crosshairs can be moved. The Min./Max.

on area values are saved together with every image.
With saved images, Min./Max on area must be activated for the

respective opened image.
> [OK] | Measurement | Min./Max. on area | [OK].

Isotherm (testo 875-2i only)

Isotherm shows temperatures in a selectable temperature range in

a uniform colour. If Isotherm is activated ( ), the quick select
buttons with the Isotherm and Emissivity... functions can be
permanently assigned and can no longer be changed.

With frozen images, the crosshairs can be moved.
> [OK] | Measurement | Isotherm | [OK].
To set the isotherm colour and range:

1. [Isotherm]

- The Isotherm dialogue is opened.

2. Move Joystick left/right to select the desired option: Isotherm

- The selected option has an orange border ( ).

3. Move Joystick up/down to change the colour or the value(s).

- Changes are applied immediately so that the effects on the

4. Close dialogue with [OK] or [Esc].

- The changes are saved.

activate/deactivate the respective function.

colour ( ), lower limit value ( ), temperature range ( ) or

upper limit value ( ).

display of the infrared image can be checked directly.

Moisture (testo 875-2i only)

The ambient temperature and humidity
measured by the (optional) radio humidity probe are used to
calculate the relative surface moisture for each pixel. The values

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values entered manually or

6 Using the product

are shown as a humidity image. The special colour palette
indicates which areas are at risk of mould:

Colour Surface moisture Assessment

green 0…64%RH non-critical

yellow/or

65…80%RH potentially critical

ange

red >80%RH critical

If this function is enabled ( ), the shortcut buttons are
permanently assigned the functions Humidity (only if no radio
humidity probe is logged on) and Emission level….

The values for relative humidity and ambient temperature are
shown at the top of the display.

1. [OK] | Measurement | [OK] | Humidity | [OK].

- If a radio humidity probe is logged on: No further information is
required.

- If no radio humidity probe is logged on: The Humidity dialogue
box is opened. The values for the ambient temperature and
humidity can be entered.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border.

3. Confirm the selection with [OK].

- The selected number is highlighted orange.

4. Move Joystick up/down to set the desired value. Move

Joystick right/left to change between the numbers.

5. Confirm the entry with [OK].

6. Confirm the settings with Apply.

Solar

To detect and document failures in photovoltaic systems, the solar
function can be selected. The sun's radiation intensity measured
(with an external instrument) can be entered for documentation
purposes. This value is saved with the IR- image.

If this function is enabled ( ), the shortcut buttons are
permanently assigned the functions Intensity and Hotspot.

The radiation intensity value is shown at the top of the display.

1. [OK] | Measurement functions | [OK] | Solar | [OK].

- The Solar dialogue box is opened. The radiation intensity value
can be entered.

2. Confirm selection with [OK].

- The selected number is highlighted orange.

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6 Using the product

3. Move Joystick up/down to set the required value. Move

Joystick right/left to switch between the numbers.

4. Confirm entry with [OK].

5. Confirm settings with [Apply].

Measuring range

The measuring range can be set to adapt to the respective area of
application.

1. [OK] | Measurement | [OK] | Measurement range.

2. Select the desired temperature range and confirm with [OK].

For measuring range 350 - 550 °C (662 - 1022 °F):

• The high-temperature filter must be installed,
dg_ref_source_inline>HT-Filter
montieren</dg_ref_source_inline>.

• With temperature differences larger than 350 K the use
of the Ironbow HT palette is recommended as it
enables lower temperatures to be shown with higher
contrast, see Palette, page 33see Mounting/removing
high-temperature filter (testo 875-2i only), page 19.

6.1.2. Image gallery

Show images…

1. [OK] | Image gallery | [OK] | Show images… | [OK].

- The Folder dialogue is opened.

- The folder name of the opened folder is displayed in the

header. ROOT designates the base folder (top level).

- The saved data is shown as preview images (image overview).
The image saved last is shown directly behind the folders.

Optional:
> Press the right [Page scroll] quick select button to change to

page scroll.

In page scroll, you can navigate in groups of 3 x 3

images/folders (page by page). To select/open an image/folder,
you must change back into Single Image.

2. Navigate:

• In page scroll: Move Joystick up/down to change between

the pages.

• In single image: Move Joystick up/down/left/right to select a

preview image/a folder (orange border).

• Open selected folder with [OK].

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6 Using the product

3. In single image: Press [OK] to open selected preview image.
Press Gallery to return to the image overview.

Delete image

1. In single image: Select image (orange border) or select and
open image.

2. Press Delete to delete the selected or open image.

- A confirmation request appears as to whether the image should
really be deleted.

3. Confirm with [OK] or cancel process with [Esc].

Create new folder

1. In the Folder dialogue: Select New Folder with the joystick and
confirm with[OK].

- The Folder name dialogue is opened.

2. Name folders: Use the Joystick to select the desired letters
and confirm with[OK].

The folder name can consist of up to 8 characters.
Incorrect entries can be deleted using the right [◄C] quick select
button.

3. Press left [Create Folder] quick select button to create the
folder.

Erase all

1. [OK] | Image gallery | [OK] | Erase all… | [OK].

- A confirmation request appears as to whether all files on the
memory card should be deleted. Folders are not deleted.

2. Confirm erase with [OK] or cancel process with [Esc].

6.1.3. Scale...

Set scale limits

You can choose between auto-scaling (continuous, automatic
adjustment to the current min./max. values) and manual scaling.
The scale limits can be set within the activated measuring range
(see Measuring range, page 28). All temperatures that undershoot
or exceed the limit value are shown in the colour of the limit value
(depending on the selected colour palette, see Palette, page 33).
Temperature ranges that are not relevant can thus be hidden.

1. [OK] | Scale… | [OK].

- The Set scale dialogue is opened.

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6 Using the product

2. Move Joystick left/right to select the desired option: Auto-

scaling ( ), min. value ( ), temperature range ( ) or max.

value ( )

- The selected option has an orange border ( ).

3. With the selection of min. value, temperature range or max.

value: Move Joystick up/down to change the value(s).

- Changes are applied immediately so that the effects on the

display of the infrared image can be checked directly.

4. Close dialogue with [OK] or [Esc].

- The changes are saved.

6.1.4. Display...

Select display options

The presentation can be adapted by means of showing/hiding the
following elements: Crosshairs, temperature scale and quick select
buttons.

Hidden function keys can be shown again by pressing a quick
select button: The first press of the button shows the function keys
again. To trigger a function, the button must be pressed again.

1. [OK] | Display… | [OK].

- The Display options dialogue is opened.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border ( ).

3. Activate ( ) or deactivate ( ) option with [OK].

4. Confirm settings with the [Apply] quick select button.

or
Discard settings with [Esc].

6.1.5. Emissivity...

Emissivity

The emissivity describes the capability of a body to emit
electromagnetic radiation. This is material-specific and must be
adapted for correct measurement results.

Non-metals (paper, ceramic, gypsum, wood, paints and coatings),
plastics and food have high emissivity, which means that the
surface temperature can be easily measured using infrared.

Because of their low or non-uniform emissivity, bright metals and
metal oxides are only somewhat suited for infrared measurement.
You must anticipate highly inaccurate measurements. A remedy for
this is coatings that increase the emissivity, e.g. paint or emission

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6 Using the product

adhesive (art. no. 0554 0051) which must be applied to the object
being measured.

The following table gives typical emissivities of important materials.
These values can be used as orientation with the user-defined
settings.

Material (material temperature) Emissivity

Aluminium, bright rolled (170 °C) 0.04

Cotton (20 °C) 0.77

Concrete (25 °C) 0.93

Ice, smooth (0 °C) 0.97

Iron, emery ground (20 °C) 0.24

Iron with casting skin (100 °C) 0.80

Iron with rolling skin (20 °C) 0.77

Gypsum (20 °C) 0.90

Glass (90 °C) 0.94

Rubber, hard (23 °C) 0.94

Rubber, soft grey (23 °C) 0.89

Wood (70 °C) 0.94

Cork (20) 0.70

Radiator, black anodised (50 °C) 0.98

Copper, slightly tarnished (20 °C) 0.04

Copper, oxidized (130°C) 0.76

Plastics: PE, PP, PVC (20 °C) 0.94

Brass, oxidized (200°C) 0.61

Paper (20 °C) 0.97

Porcelain (20 °C) 0.92

Black paint, matt (80 °C) 0.97

Steel, heat-treated surface (200 °C) 0.52

Steel, oxidized (200) 0.79

Clay, burnt (70 °C) 0.91

Transformer paint (70 °C) 0.94

Brick, mortar, plaster (20 °C) 0.93

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6 Using the product

Reflected temperature

Using this offset factor, the reflection is calculated out due to the
low emissivity and the accuracy of the temperature measurement
with infrared instruments is improved. In most cases, the reflected
temperature is identical to the ambient air temperature. Only when
objects with strong emissions with much higher temperatures (such
as ovens or machines) are in the proximity of the object being
measured should the radiation temperature of theses heat sources
be determined and used (e.g. using a globe thermometer). The
reflected temperature has only little effect on objects with high
emissivity.

Set emissivity/reflected temperature

You can choose between a user-defined emissivity and 8 materials
with recorded emissivities.
The reflected temperature can be set individually.

1. [OK] | Emissivity… | [OK].

- The Emissivity dialogue is opened.

2. Move Joystick up/down to select the desired material.

- The selected material is highlighted orange ( ). The

3. Move Joystick to the right to switch to the setting of the

- The selected option has an orange border ( ).

4. Confirm the selection with [OK].

- The selected number is highlighted orange ( ).

5. Move Joystick up/down to set the desired value. Move

6. Confirm the entry with [OK].

7. Confirm the settings with Apply.

- The changes are saved.

The designation of the materials in the selection list is
configured during commissioning of the thermal imager in
the language selected by the user. A translation does not
occur in the event of subsequent changeover of the
language in the instrument.

Using the PC software, other materials can be imported into
the instrument from an existing list. The language for the
materials here depends on the operating system language
of the PC.

corresponding emissivity is shown to the right next to the
material.

emissivity (only available when selecting User defined) or to

Reflected temp..

Joystick right/left to change between the numbers.

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- The selected emissivity ( ) is shown at the bottom right in the
display in measurement view.

6.1.6. Palette

Change colour palette for the infrared image

You can choose between 10 existing palettes. The Ironbow HT
palette is intended specifically for measurements in the high­temperature measuring range (low temperatures are shown with
higher contrast). The currently activated option is marked with a tick

().

1. [OK] | Palette| [OK].

2. Move Joystick up/down to select the desired option.

3. Confirm the selection with [OK].

6.1.7. Configuration

Time/date...

Time and date can be set. Time and date format are automatically
set based on the selected instrument language.

1. [OK] | Configuration… | [OK] | Time/date… | [OK].

- The Set time/date dialogue is opened.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border ( ).

3. Confirm the selection with [OK].

- The selected number is highlighted orange ( ).

4. Move Joystick up/down to set the value. Move Joystick
right/left to change between the numbers.

5. Confirm the entry with [OK].

6. Confirm the settings with Apply.

6 Using the product

Country settings…

Instrument language and temperature unit can be set.

1. [OK] | Configuration… | [OK].| Country settings… | [OK].

- The Country settings dialogue is opened.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border ( ).

3. Confirm the selection with [OK].

- The selected setting is highlighted orange ( ).

4. Move Joystick up/down to change the setting.

5. Confirm the entry with [OK].

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6 Using the product

6. Confirm the settings with Apply.

Optics...

The lenses adjusted to the instrument are shown. Only the lenses
that are shown may be used.

testo 875-2i: The high-temperature filter registered in the
instrument is shown. With use of another high-temperature filter,
the specified accuracy is not ensured.

> [OK] | Configuration… | [OK] | Optics… | [OK].
Using the Protection glass option, you can set whether an infrared

protection glass is used or not. Ensure the correct setting to
prevent corruption of the measurement results.

> Press [OK] to activate ( ) or deactivate ( ) the Protection

- With the option activated, the protection glass symbol ( ) is

SuperResolution (optional)

SuperResolution is a technology to improve image quality. Each
time an image is recorded, a sequence of images is saved on the
thermal imager and used to calculate a higher-resolution image
with the aid of the PC software (no interpolation). The pixel count
increases by a factor of 4, while the geometric resolution (IFOV) is
improved by a factor of 1.6.
To use the function, the imager must be hand-held (no tripod).

glass option.

shown in the bottom right of the display.

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6 Using the product

This function is available as an additional option (article
no. 0554 7806) and must be activated before it can be
used, if the option was not ordered at the same time as
the imager.

Activate function (only with subsequent order):

You will receive an envelope with an access code
(identification code)

When all necessary data has been entered, an
activation code is generated and can be used to
activate the function via the IRSoft PC software. Please
observe the installation requirements and steps on the
website or in the email sent to you.

Activate/deactivate function:

1. [OK] | Configuration… | [OK] | SuperResolution | [OK].

2. Press [OK] to activate ( ) or deactivate ( ) the

SuperResolution option.

3. Confirm the settings with [Apply].

When you save an image, an information window with the image
file name is displayed. If SuperResolution is activated ( ), SR is

also displayed after the file name.

Power-save options…

Options can be set to extend the rechargeable battery running time.

1. [OK] | Configuration… | [OK] | Power-save options… | [OK].

- The Power-save options dialogue is opened.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border ( ).

3. Confirm the selection with [OK].

- LCD backlight: The selected setting is highlighted orange and

can be changed ( ).

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6 Using the product

> Move Joystick up/down to change the setting. Confirm the

- Switch off LCD or Power off imager: The selected option can

> Press [OK] to activate ( ) or deactivate ( ) the function.

4. Confirm the settings with [Apply].

Radio…( testo 875-2i only)

A radio humidity probe can be logged onto the instrument.
The function Radio… can only be selected if a radio module is

connected (accessory), see Inserting a radio module (accessory,
testo 875-2i only), page 18.

Every radio probe has a probe identification number (RFID). This is
made up of the three-digit RFID number on the probe and the
position of the switch in the battery compartment of the radio probe
(H or L). To be logged on at the instrument, the radio probe must
be switched on and the transfer rate must be set to 0.5 sec. This
occurs by briefly pressing the on/off button when switching on (also
see instructions for use of radio probe).

1. [OK] | Configuration… | [OK] | Radio… | [OK].

- The Radio... dialogue box is opened.

- The probe-IDs of the radio probes found are displayed.
If no radio probe was found, this may be because of the following:

• The radio probe is not switched on or the battery of the radio

• The radio probe is outside the range of the instrument.

• Sources of interference are influencing radio transmission (e.g.

> If necessary: Rectify the possible causes of the fault in radio

2. Press [OK] to enable ( ) or disable ( ) the radio

3. Move Joystick right to switch to a list of the radio probes found.

4. Move Joystick up/down to select a probe.

-

5. Confirm selection with Apply.

entry with [OK].

be activated or deactivated.

- With the option activated, the length of time until shut-down
can be set.

> Move Joystick to the right and press [OK]. Move Joystick

up/down to change the setting. Confirm the entry with [OK].

probe is spent.

reinforced concrete, metal objects, walls or other barriers
between transmitter and receiver, other transmitters of the
same frequency, strong electromagnetic fields).

transmission.

connection.

The selected probe is highlighted orange ( ).

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6 Using the product

If no readings appear during the measurement:
> Check the potential causes, see above.

Audio settings…(testo 875-2i only)

The volume of the audio playback and recording can be set.

1. [OK] | Configuration… | [OK] | Audio settings… | [OK].

- The Audio settings... dialogue is opened.

2. Move Joystick up/down to select the desired option.

- The selected option has an orange border ( ).

3. Move Joystick left/right to change the setting.

4. Confirm the settings with [Apply].

Format…

The memory card can be formatted. During the formatting, all
saved data on the SD card is lost.

1. [OK] | Configuration… | [OK] | Format… | [OK].

- A confirmation request appears as to whether the memory card
should really be formatted.

2. Confirm with [OK] or cancel process with [Esc].

Factory reset

The instrument settings can be reset to the factory settings.
Time/date and country settings are not reset.

Please note: After a factory reset, the numbering of images begins
anew. When saving images, images that have already been saved
and have the same number are overwritten!

> Transfer all saved images onto a PC before performing a reset

to prevent possible overwriting.

1. [OK] | Configuration… | [OK] | Factory settings… | [OK].

- A confirmation request appears as to whether the instrument
should really be reset to the factory settings.

2. Confirm reset with [OK] or cancel process with [Esc].

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6 Using the product

6.2. Measuring

NOTICE

Damage to the infrared detector by measuring high scene
temperatures.

> testo 875i without high-temperature filter: do not direct the

thermal imager at areas > 500°C / 932°F.

> testo 875-2i with high-temperature filter: do not direct the

thermal imager at areas > 800°C / 1472°F.

testo 875-2i: When measuring temperatures > 350°C or
> 662°F, always install the high-temperature filter, see
Mounting/removing high-temperature filter (testo 875-2i
only), page 19, and adjust the high-temperature
measurement range, see Measuring range, page 28.

With the high-temperature measuring range (350.0 -

550.0 °C or 662.0 - 1022 °F) activated, the stated accuracy

specifications are not valid for readings below 350 °C or
662 °F as this range is not calibrated.

Important framework conditions

Please observe the following framework conditions in order to
obtain significant measurement results.

Humidity measurement (only testo 875-2i):

• Pivot radio humidity probe or separate humidity measuring

instrument slightly to shorten the adjustment time. (e.g.
breathed air).

Building thermography, investigating the building shell:

• Considerable temperature difference between inside and

outside required (ideal: > 15 °C/> 27 °F).

• Consistent weather conditions, no intensive sunlight, no

precipitation, no strong wind.

To ensure the highest level of accuracy, the imager requires an
equalization period of 5 minutes after being switched on.

Important settings

Before recording an image, check whether the protection glass
option is set correctly to prevent corruption of the measurement
results, see Optics..., page 34.

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Before saving an image, ensure that it is focused correctly (in
focus), see Manually focusing the image, page 21. Images that are
not in focus cannot be corrected retroactively!

To obtain precise readings, the emissivity and reflected
temperature must be set correctly, see Set emissivity/reflected
temperature, Seite 32. A subsequent adjustment is possible via
the PC software as required.

With an activated auto scaling, the colour scale is continuously
adapted to the min./max. values of the current measurement
image. The colour that is to be assigned to a specific temperature
thereby changes constantly. To be able to compare multiple
images by means of the colouring, the scaling must be manually
set to fixed values, see Scale... page 29 or must be subsequently
adjusted to uniform values using the PC software.

Depending on the scene temperature, the measuring range
may be undershot or exceeded. In this case, --- or +++ is
shown instead of the readings.

> If this occurs, change the measuring range, see

Measuring range, page 28.

Select the storage location (folder)

1. While an image is frozen (fixed image): Press the left [Folder]
quick select button.

- The Folder dialogue is opened.

To create a new folder, see Create new folder, Seite 29.

2. Select the desired folder with the joystick and open with [OK].

- The folder name of the opened folder is displayed in the
header.

3. Press left [Apply] quick select button to select the opened
folder.

Recording/playing audio comments (testo 875-2i only)

It is only possible to record an audio comment for frozen images. It
is possible to play audio comments with frozen and saved pictures.

1. While an image is frozen (fixed image): Press the right [Audio]
quick select button.

- The Audio dialogue is opened.

2. Select the desired function with the joystick and confirm with

[OK].

• Record audio comments:

1. Start recording: Press [].

2. Stop recording: Press [].
> Continue recording: Press [] again.

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6 Using the product

• Play recording:

1. Select beginning of recording: Press [] again.

2. Start playback: Press [].

3. Stop playback: Press [].
> Continue playback: Press [] again.

• Change audio comment:

1. Selection position from which the recording should be

overwritten: Begin playback with [] and stop at the
desired point [].

2. Use [] to overwrite the recording as of the desired point.

• Delete recording:

> Press [].

- The complete recording is deleted.

• Exit Audio dialogue:

> Press [ESC].

Aiming at the measuring surface

Using the laser, the measuring surface can be aimed at.

WARNING

Eye damage due to laser beam!

> Do not look into the laser beam.
> Do not point the laser beam at people.

To change the quick select button functions, see Changing
assignment of the quick select buttons, page 23.

> Press and hold [Laser].

- When the laser is active, the laser symbol ( ) flashes.

Caution: Laser and lens have a different angle of view due
to the spacial separation. The laser sighting and the centre
of the image thus do not correspond completely (parallax
error). The laser dot is therefore not suitable for marking
locations that were aimed at using the crosshairs.

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7 Maintaining the product

Changing the battery

To prevent losing the instrument settings: Only change the
rechargeable battery when a buffer battery is inserted in the
instrument or the mains unit is connected.

1. Press lock release button.

- The rechargeable battery is released and sticks out a little from
the rechargeable battery slot. The locking function keeps the
battery from falling out.

2. Completely remove the battery from the rechargeable battery
slot.

3. Insert a new battery into the rechargeable battery slot until this
is flush with the bottom of the handle.

- The thermal imager starts automatically.

Clean thermal imager

> If the housing of the thermal imager is dirty, clean it with a damp

cloth. Do not use any aggressive cleaning agents or solvents!
Weak household cleaning agents and soap suds may be used.

Cleaning lens/ protection glass/high-temperature filter

> Large dust particles can be removed with a clean optical

cleaning brush (available in specialized photography shops).

> Use a lens cleaning cloth for slight contamination. Do not use

rubbing alcohol!

7 Maintaining the product

Change buffer battery

To prevent losing the instrument settings: Only change the buffer
battery when a charged rechargeable battery is inserted or the
mains unit is connected.

1. Open the cover on the left side of the thermal imager.

2. Remove battery holder, including buffer battery, from the battery
slot.

3. Remove empty battery from the holder and insert new battery
(type CR 1632).

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7 Maintaining the product

NOTICE

Incorrectly inserted batteries can lead to damage of the
product!

> When inserting the batteries, observe the polarity (label on the

battery holder).

4. Insert battery holder into the battery slot.

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8 Tips and assistance

8.1. Questions and answers

Question Possible causes/solution

Message Backup battery

empty or not present is

shown.

Error No memory card

inserted! is shown.

1. Confirm the message with [OK].

2. Change buffer battery, see
Change buffer battery page 41.

Memory card defective or not inserted.

1. Confirm the message with [OK].

2. Check or insert memory card.

Error Memory card full! is
shown.

Insufficient memory present.

1. Confirm the message with [OK].

2. Insert new memory card.

Error No lens/wrong lens!
is shown.

Message Charging not

possible! is shown.

1. Switch off thermal imager.

2. Check lens.

Ambient temperature is outside the
permissible range for charging the
battery.

1. Confirm the message with [OK].

2. Keep to the permissible ambient
temperature.

Error Permissible

instrument temperature
exceeded! is shown.

1. Switch off thermal imager.

2. Let instrument cool off and keep to
the permissible ambient
temperature.

--- or +++ is shown instead

of the reading.

Reading is outside of the measuring
range.

> Change measuring range.

xxx is shown instead of the

reading.

Reading cannot be calculated.
> Check parameter settings for

plausibility.

Measurement function

Humidity: No readings

from the radio probe are
shown.

Radio probe not logged on or sources
of interference in the radio
transmission:

> Check possible causes, see

Radio…( testo 875-2i only), page

36.

8 Tips and assistance

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8 Tips and assistance

If we could not answer your question, please contact your dealer or

8.2. Accessories and spare parts

Testo Customer Service.

Description Article no.

Lens protection glass 0554 8805

High-temperature filter (Retrofitting, testo 875-2i
only)

Telephoto lens (testo 875-2i only) on request

Radio humidity probe (testo 875-2i only) on request

Super Resolution 0554 7806

Emission adhesive 0554 0051

Rech. batt. 0554 8802

Desktop charging station 0554 8801

Tripod 0554 8804

Mains unit 0554 8808

SD card 0554 8803

USB cable 0449 0047

ISO calibration certificate for thermal imager:

• Calibration points 0 °C, 25 °C, 50 °C
in measuring range -20 °C - 100 °C

• Calibration points at 0 °C, 100 °C, 200 °C in
measuring range 0 °C to 350 °C

on request

0520 0489

0520 0490

44

For further accessories and spare parts, please refer to the product
catalogues and brochures.

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Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

0970 8754 en 01 V01.00 en

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com