Multifunction HVAC Instruments

Testo 400 universal IAQ instrument – features

Impressive IAQ measurement technology

1. High-precision, location-independent, built-in differential pressure sensor
2. Integrated absolute pressure sensor
3. Measures all IAQ-related parameters: Flow, temperature, humidity, pressure, illuminance, radiant heat, turbulence, CO2 and CO
4. Numerous connection options for probes: 2 x cable probes (TUC), 4 x Bluetooth® probes, 2 x type K thermocouple probes
5. Compatible with a wide range of available Bluetooth® and cable probes – so you’ll be equipped for any measuring task
6. For high-precision measurements and less downtime: Adjustment function at up to six measuring points for zero-error display, probe heads can be replaced without restarting the IAQ measuring instrument, high-quality probes with an intelligent calibration concept (probe calibration independent of the measuring instrument)
7. Long-term monitoring of the indoor air quality: Order the IAQ data logger for carrying out long-term measurements with the testo 400 IAQ measuring instrument. While the stand-alone data logger is carrying out the IAQ measurement, you can use the IAQ measuring instrument for measurements elsewhere

Smart, intuitive, practical: Measurement programs, measurement data management and operation

1. For error-free measurements in accordance with the standards: Smart, intuitive measurement menus and evaluation of readings provide optimum support for your measuring task. Use the measurement programs for standard-compliant measurements: HVAC grid measurement as per EN ISO 12599 and ASHRAE 111, PMV/PPD as per EN ISO 7730 and ASHRAE 55, draught and turbulence as per EN ISO 7730 and ASHRAE 55, WBGT measurement as per DIN 33403 and EN ISO 7243, NET measurement as per DIN 33403
2. Complete the measurement and full documentation including photos, comments and your own logo on site at the customer’s premises, and send by e-mail (via WLAN)
3. Customer and measuring point management is carried out in the measuring instrument itself – for efficient work on site
4. Smart-touch display for intuitive operation of the IAQ measuring instrument
5. testo DataControl PC software for further analysis, archiving and documentation of measurement data on your computer
6. Built-in WLAN and Bluetooth® interfaces: Send measurement reports directly on site or print them out with a suitable printer

Testo 440 air velocity and IAQ measuring instrument in combination with high-quality probes to measure and store all air velocity and IAQ parameters (please order probes separately). Up to 3 probes can be connected simultaneously: a Bluetooth probe, a wired probe and a temperature probe with type K thermocouple connector. Automatic probe detection and clearly structured measurement menus guarantee simple operation and will make your day-to-day work easier.

Measure in just a few clicks with the testo 440 multifunction measuring instrument

Carry out your measurements quickly and easily: the air velocity and IAQ measuring instrument automatically detects each connected probe. This means that there is no need for you to manually reset the parameters when changing probes. Clearly structured measurement menus for measuring the volume flow in ducts/at outlets, funnel measurement, measuring the degree of turbulence, determining the cooling/heating output, mould detection and long-term measurement provide you with optimum support during your day-to-day work.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space.

The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case. It makes it possible to carry out measurements without any bothersome cable connection and it transfers readings up to a distance of 20 m. Or as a practical alternative, use the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted.

Practical measurement data management

The multifunction measuring instrument stores up to a max. 7500 measurement protocols, which can be read via a USB port and further processed as a CSV file on your computer (e.g. with Excel). With the testo BLUETOOTH/IRDA printer (please order separately), you have the option of producing a report printout of the measurement data directly on site.

Intelligent calibration concept for maximum precision

You can rely on accurate measurement results when using our digital probes, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probes in for calibration. The multifunction measuring instrument can therefore remain in continuous use.

Advantages of measuring with the testo 440 air velocity and IAQ measuring instrument

Precise and reliable in ducts and at air outlets

1. Large range of connectable probes: hot wire and vane probe (Ø 16 mm) for measurements in ducts; large vane probes of Ø 100 mm for measurements at air/ceiling outlets
2. Calculate volume flow quickly: in the measurement menu, simply configure the dimensions and geometry of the duct cross-section and see the volume flow displayed on the measuring instrument straight away
3. You will even find it easy to carry out measurements in particularly large ducts. This is because the extendable telescope on the hot wire and vane probe (Ø 16 mm) with universal handle can be further extended using the telescope extension – enabling you to attain a total length of 2 metres
4. Carry out measurements at air/ceiling outlets effortlessly and without using a ladder. Fit the vane probe (Ø 100 mm) with the extendable telescope with 90° angle and, if necessary, with the telescope extension (both can be ordered separately)
5. Use the vane probes in conjunction with the testovent measurement funnels and flow straighteners to test incoming / outgoing air at plate outlets, ventilation grilles and swirl outlets
6. Practical Bluetooth interface: use the air velocity probes to measure without having to deal with any bothersome cables, operate the measuring instrument by pressing the button on the handle of the probe, e.g. start or stop a timed mean calculation
7. Use the practical magnets to securely attach the multifunction measuring instrument to metal surfaces (e.g. ventilation ducts) 

Long-term monitoring of indoor air quality 

1. The right probe for your requirements: probes for CO2, CO, air temperature and humidity are available as variants with Bluetooth or with fixed cable
2. Easy to use: enter the measurement period and interval in the menu for long-term measurement and track it over the course of the day
3. Internal memory for up to 7500 measurement protocols

Turbulence measurement in accordance with EN ISO 7730 / ASHRAE 55 

1. Attain a high level of accuracy, even at low air velocities, with a turbulence probe
2. Automatic calculation of draught risk and degree of turbulence in accordance with EN ISO 7730/ASHRAE 55
3. For convenient measurements at varying heights, we recommend using our measuring tripod for comfort level measurement. This makes it very easy to position turbulence probes in compliance with the standards 

Range of probes for cleanrooms and laboratories 

1. Fume cupboard probe for high-precision air velocity measurement on fume cupboards
2. Thanks to the low start-up speed of 0.1 m/s, the high-precision vane probe (Ø 100 mm) is ideal for laminar flow measurements in cleanrooms. Available as a variant with Bluetooth or with fixed cable
3. High-precision temperature/humidity probe (0636 9771 or 0636 9772) with an accuracy of ±(0.6% RH + 0.7 % of m.v.) in the range 0 to 90% RH for measuring the humidity in cleanrooms

Testo 440 air velocity and IAQ measuring instrument in combination with high-quality probes to measure and store all air velocity and IAQ parameters (please order probes separately). Up to 3 probes can be connected simultaneously: a Bluetooth probe, a wired probe and a temperature probe with type K thermocouple connector. Automatic probe detection and clearly structured measurement menus guarantee simple operation and will make your day-to-day work easier.

Measure in just a few clicks with the testo 440 multifunction measuring instrument

Carry out your measurements quickly and easily: the air velocity and IAQ measuring instrument automatically detects each connected probe. This means that there is no need for you to manually reset the parameters when changing probes. Clearly structured measurement menus for measuring the volume flow in ducts/at outlets, funnel measurement, measuring the degree of turbulence, determining the cooling/heating output, mould detection and long-term measurement provide you with optimum support during your day-to-day work.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space.

The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case. It makes it possible to carry out measurements without any bothersome cable connection and it transfers readings up to a distance of 20 m. Or as a practical alternative, use the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted.

Practical measurement data management

The multifunction measuring instrument stores up to a max. 7500 measurement protocols, which can be read via a USB port and further processed as a CSV file on your computer (e.g. with Excel). With the testo BLUETOOTH/IRDA printer (please order separately), you have the option of producing a report printout of the measurement data directly on site.

Intelligent calibration concept for maximum precision

You can rely on accurate measurement results when using our digital probes, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probes in for calibration. The multifunction measuring instrument can therefore remain in continuous use.

Advantages of measuring with the testo 440 air velocity and IAQ measuring instrument

Long-term monitoring of indoor air quality 

1. The right probe for your requirements: probes for CO2, CO, air temperature and humidity are available as variants with Bluetooth or with fixed cable
2. Easy to use: enter the measurement period and interval in the menu for long-term measurement and track it over the course of the day
3. Internal memory for up to 7500 measurement protocols

Use the probe with the compatible testo multifunction measuring instrument (please order separately) to determine CO2 concentration, air humidity and air temperature. Wet bulb temperature, dew point and absolute humidity are calculated at the same time.

CO2 probe with Bluetooth including temperature and humidity sensor – features

Use the probe to check the indoor climate, for example in offices, production areas or storage facilities. To ensure accurate measurement results, air density compensation is carried out via the integrated absolute pressure measurement. The readings of the CO2 probe are transmitted to your measuring instrument via Bluetooth, up to a distance of 20 m.

Particularly useful: store individual readings directly in the measuring instrument by pressing the button on the probe. The clearly structured measurement menu for long-term measurement enables the measuring instrument to be operated intuitively. Reading trends are reliably recorded thanks to the convenient input of measurement time and measuring cycle. You can use these trends to evaluate changes in the indoor air quality.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space. The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case.

Or order the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted. If the sensors (CO2, humidity, temperature) need to be replaced in the distant future, you can change the probe head.

Intelligent calibration concept

You will get exceptionally accurate measurement results with the digital probe, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probe head in for calibration – so the measuring instrument remains in continuous use.

Areas of application for the CO2 probe with Bluetooth

Use the CO2 probe including temperature and humidity sensor to check the indoor climate (indoor air quality), e.g. in offices, production areas or storage facilities.

The CO2 concentration is a primary indicator of indoor air quality. Poor air quality due to excessive CO2 concentration results in tiredness and lack of concentration, and can even cause illnesses. The CO2 concentration should therefore not normally exceed 1,000 ppm

The easy-to-use testo 480 is a high-precision digital temperature, humidity and air flow meter which allows you to measure, analyze and log all relevant ventilation and indoor air quality parameters with only one device.

The high-precision digital temperature, humidity and air flow meter is designed to provide independent experts, consultants, technical service providers and HVAC technicians in the field of ventilation and indoor air quality with an efficient means of carrying out all their measurements – i.e. norm-compliant setting and adjustment of airconditioning and ventilation systems in offices, residential and industrial buildings –using just one single device.

It is also designed to check quality parameters in production and processing quickly and reliably.

To know more about the applications that the testo 480 digital temperature, humidity and air flow meter can be used for, please click on the tab labeled applications.

The intelligent concept behind the testo 480

The testo 480 has a built-in, high-precision difference pressure sensor for pitot static tube measurements and filter/clean room monitoring. There is also a wide range of high-quality optional sensors for carrying out the following measurements:

-  Air flow and volume flow(also fume cupboard measurements)
-  Temperature
-  Humidity
-  Pressure (difference and absolute pressure)
-  CO2
-  Illumination intensity
-  PMV/PPD
-  Heatradiation
-  Degreeofturbulence
-  WBGTIndex

The testo 480 digital temperature, humidity and air flow meter comes with a wide range of optional sensors and accessories – like the wireless testo quick printer for print outs on site –which allows you to customize your meter to suit your own pocket and meet your own needs.

State-of-the-art technology for HVAC technicians and experts

The testo 480 was designed to make your work more efficient and life easier. The high-quality, easy-to-use digital temperature, humidity and air flow meter can be used to measure all relevant ventilation and air conditioning parameters and carry out long-term measurements with only one device with a huge memory that can save up to 60 million measurements and a set of integrated programs that guide you through the following measurements step by step.

-  VAC measurements in compliance with EN 12599
-  Degree of turbulence measurementsin compliance with EN 12599
-  PMV/PPD measurement in compliance with ISO 7730
-  WBGT measurement in compliance with ISO 7243

Easy Climate PC software

The “Easy Climate” software allows your readings to be transferred directly to a PC via a USB cable where they can then be presented, analyzedor logged. A specially developed protocol designer enables you to create protocols to suit your customers’ needs and the optional testoquick printer provides you with printouts on site.

Digital sensors and intelligent calibration concept

The optional testo digital sensors provide you with highly accurate results as there is no measurement inaccuracy from the meter. In addition, any deviations which are determined during calibration can be saved to the digital sensor. These deviations are compensated automatically giving you a zero error value. The intelligent sensors alert the user when the next calibration – which can be carried out by hand thereby ensuring that you always have your meter with you when you need it – is due.

The testo 480 digital temperature, humidity and air flow meter has a built-in, high-precision difference pressure sensor with a measuring range from -100 to +100 hPa and connection possibilities for a further three optional digital and two temperature (type Kthermocouple sensors)

Ventilation and air conditioning systems are used more and more frequently to ensure user independent fresh air supply and thermal comfort in buildings. The testo 445 climate measuring instrument helps you check the system is functioning properly and operating efficiently. This is because the measuring instrument can determine all the relevant measurement parameters for you.

testo 445 climate measuring instrument: an overview of the advantages

The testo 445 climate measuring instrument has two inputs for connecting external probes (which can be ordered separately). At Testo, you have a large selection of suitable probes for the testo 445 climate measuring instrument. Depending on which probe you decide on, you can determine the following parameters:

1. Air velocity (in ventilation ducts, at duct outlets and on extractors)
2. Volume flow
3. Temperature
4. Relative air humidity
5. Dew point
6. Absolute humidity
7. Degree of humidity
8. Enthalpy
9. Pressure
10. CO in indoor air

Further practical features of the climate measuring instrument: its internal memory records up to 3,000 readings. The automatic allocation of the duct cross-section is also particularly useful. This means you can save the measurement data so that it is linked to the measuring location (up to 99 measuring locations). The mean value, the last measured value and the min./max. values can be displayed simply by pressing a key.

As optional accessories for the climate measuring instrument, we recommend you get the testo fast printer to print data out directly at the measuring location and the ComSoft software for convenient data analysis on the PC

The multifunction IAQ meter allows you to carry out a variety of different measurements which enable you to inspect and adjust ventilation and air conditioning systems and carry out indoor air quality testing. In addition to the many other functions and features which its smaller brother, the 435-2, has, the testo 435-4 also has an integrated pressure difference sensor for measurements with pitot static tube and filter monitoring.

Find out which benefits the multifunction meter testo 435-4 provides

The testo 432-4 is extremely versatile and can measure a host of variables including air temperature, air flow, volumetric flow rate, humidity and lux. And because you know best what your multifunction meter needs to be able to do, you can configure it accordingly by connecting any one of the many optionally available sensors and probes.

In addition to the sensors which can be connected directly to the meter, you can also connect up to 3 wireless sensors via an optionally available wireless module. The meter can pick up the measurements via the wireless sensors over a distance of up to 20 meters. This allows you to carry out quick and easy measurements at places which would otherwise be extremely difficult or virtually impossible to reach.

There’s also a special optionally available carry case that can hold not only your meter but also all the probes and sensors that make up your individual set.

Multiple features, yet easy to use

The testo 435-4 multifunction IAQ meter is designed to work quickly and efficiently without a need for laboriously programmed.
Sensor dependent menus and selectable user profiles for typical applications like “duct measurements” and “indoor air quality testing” ensure that the meter is always ready to use. The testo 435-4 has a super-size memory that can save up to 10,000 measurements, which can be transferred to your laptop or PC via the included USB cable. The included software allows you to log, archive and clearly structure all relevant measuring data and measuring programmes, for example duct measurements. Specially adapted measurement protocols can be used to present your customers with data from duct, long-term and degree of turbulence measurements. The optionally available testo fast printer can be used to provide your customers with on-the-spot protocol print outs.

The testo 453-4 has a large, easy-to-read backlit display that shows the dew point difference along with other values including min, max and mean values. A durable protective cover protects the testo 435-4 multifunctionindoor air quality meter reliably against impact

The testo 435-3 version of testo 435 multi-function climate measuring instrument has an integrated differential pressure sensor with a 0… 25 hPa measuring range. Differential pressure measurement enables you to check filters in ventilation and air conditioning systems or to measure air velocity with a Pitot tube (optional).
Hence testo 435-3 multi-function climate measuring instrument with its optional probes ideally equips you for adjusting ventilation and air conditioning systems or assessing air quality.

Attachable probes (optional) for assessing air quality
-  IAQ probe (Indoor Air Quality) for assessing air quality – measures CO2, air temperature, air humidity and absolute pressure
-  Ambient CO probe for CO measurement in buildings and rooms
-  Globe thermometer for measuring radiant heat
-  Temperature probe for measuring air temperature, core temperature and surface temperature

Attachable probes (optional) for adjusting and testing ventilation and air conditioning systems
-  Thermal anemometers for measuring air velocity and volumetric flow in ventilation ducts. If you also want to measure the temperature and air humidity in ducts, we recommend you use the thermal anemometer with integrated temperature and air humidity measurement
-  Vane anemometer with a small diameter (Ø 16 mm) for measuring air velocity and volumetric flow in ventilation ducts
-  Vane anemometer with a large diameter (Ø 100 mm) for measuring volumetric flow at the air outlet. Also for measurements at poppet valves and ventilation grilles in combination with the testo vent 417 funnels or for measurements at swirl outlets with the volume flow straightener
-  Temperature probe for measuring air temperature, core temperature and surface temperature
-  Absolute pressure probe

The service cases which are also available offer you space for the climate measuring instrument and your whole range of probes

The testo 435-4 version offers even more possibilities for adjusting and testing air conditioning systems and measuring air quality. Further probes, such as lux probes or probes for turbulence level measurement, can be attached to this measuring instrument.

Complex technology, but really easy handling
The testo 435-3 multi-function climate measuring instrument is characterized by an efficient measuring process which makes any inconvenient programming of the measuring instrument superfluous: probe-dependent menus and selectable user profiles for the typical applications of “duct measurement” and “IAQ measurement” ensure the easiest imaginable handling.

It also offers legibility on the large display with an illumination function which also displays dew point distance, min., max. and mean values. A solid housing provides reliable protection against impacts for the testo 435-3 multi-function climate measuring instrument.

Documentation of measurement data on site
The testo fast printer, which is available as an option, means you can create a report printout of measurement data directly on site. For a duct measurement, you can for instance print out the current readings or the min./max. values for air velocity, volumetric flow, temperature and air humidity. You can use the printout as evidence of your work.

Use the practical cyclical printing function on the testo 435-3 as well. It not only enables the printout of individual readings, but also of whole series of measurements on the testo fast printer at freely adjustable intervals (for example once a minute).

We recommend you use the testo 435-4 version for saving, documenting and archiving measurement data. It is equipped with a reading memory and PC software

Testo 435-2 indoor air quality meter is designed to allow you to carry out all the measurements that are necessary to check and adjust ventilation and air conditioning systems and assess the indoor air quality.

A wide selection of optional probes and sensors with the IAQ meter gives you the freedom to configure your meter just the way you want it. Order your probes and sensors along with your meter now.

Connectable sensors (optional) for Indoor Air Quality testing

1. IAQ sensor for assessing the indoor air quality using CO2, air temperature, relative humidity and absolute pressure measurements
2. Comfort sensor for degree of turbulence measurements in compliance with EN 13779 for the objective assessment of the air velocity in the relevant room
3. Globe thermometer for measuring radiation heat
4. Lux sensor for measuring illumination
5. Moisture/temperature sensor for assessing the thermal comfort in the relevant room
6. CO environmental sensor for measuring CO in rooms and buildings
7. Temperature sensor for immersion, penetration, air and surface measurements
8. Temperature sensors to determine the HTC value

Connectable sensors (optional) for checking and adjusting ventilation and air conditioning systems

1. Thermal anemometer, also with integrated temperature and relative humidity measurement function for air velocity and volume flow rate measurements in ventilation ducts
2. Impeller anemometer with small diameter(Ø 16mm) for air flow and volume flow rate measurements in ventilation ducts
3. Impeller anemometer with large diameter (Ø 100mm) for  air flow and volume flow rate measurements at air outlets in connection with the testovent 417 funnels also for carrying out measurements at disk valves and ventilation grilles or for carrying out measurements at ceiling diffusers using a volume flow rate rectifier
4. Temperature sensor for immersion, penetration, air and surface measurements
5. Moisture/temperature sensor for carrying out measurements in ventilation ducts
6. Absolute pressure sensor

In addition to the other connectable sensors, you can also connect as many as three wireless sensors to your testo 435-2 IAQ meter: the optionally available wireless module allows you to carry out wireless temperature and moisture measurements via wireless sensors across distances of up to 20 meters out in the open. This helps to ensure that the cable is not damaged and that nothing gets in your way while measuring.

There is also a separate carry case available that provides you with plenty of room for both your meter and your selection of probes and sensors.

Complex technology that could hardly be more simple

The beauty behind testo 435-2 indoor air quality meter is that the whole measuring process can be carried out quickly and efficiently without any complex programming.
Sensor dependent menus and selectable user profiles for typical applications like “duct measurements” and “IAQ measurements” ensure that the meter is always ready to use.The testo 435-2 has a super-size memory that can save up to 10,000 measurements, which can be transferred to your laptop or PC via the included USB cable. The included software allows you to log, archive and clearly structure all relevant measuring data and measuring programmes, for example duct measurements. Specially adapted measurement protocols can be used to present your customers with data from duct, long-term and degree of turbulence measurements. The optionally available testo fast printer can be used toprovide your customers withon-the-spot protocol print outs.

The testo 453-2 has a large, easy-to-read backlit display that shows the dew point difference along with other values including min, max and mean values. A durable protective cover protects the testo 435-2 indoor air quality meter reliably against impact

Testo 435 multi-function measuring instrument is available in four versions. This testo 435-1 version is the entry-level measuring instrument for adjusting and testing ventilation and air conditioning systems and for assessing air quality. Optional probes for various measurements which can be connected to the testo 435-1 are also available.

Attachable probes (optional) for assessing air quality

1. IAQ probe (Indoor Air Quality) for assessing air quality – measures CO2, air temperature, air humidity and absolute pressure
2. Ambient CO probe for CO measurement in buildings and rooms
3. Globe thermometer for measuring radiant heat
4. Temperature probe for measuring air temperature, core temperature and surface temperature

Attachable probes (optional) for adjusting and testing ventilation and air conditioning systems

1. Thermal anemometers for measuring air velocity and volumetric flow in ventilation ducts. If you also want to measure the temperature and air humidity in ducts, we recommend you use the thermal anemometer with integrated temperature and air humidity measurement
2. Vane anemometer with a small diameter (Ø 16 mm) for measuring air velocity and volumetric flow in ventilation ducts
3. Vane anemometer with a large diameter (Ø 100 mm) for measuring volumetric flow at the air outlet, also for measurements at poppet valves and ventilation grilles in combination with the testo vent 417 funnels or for measurements at swirl outlets with the volume flow straightener
4. Temperature probe for measuring air temperature, core temperature and surface temperature
5. Absolute pressure probe

Service cases to offer you space for the climate measuring instrument and your whole range of probes are also available.

The testo 435-2, testo 435-3 or testo 435-4 versions offer even more possibilities for adjusting and testing air conditioning systems and measuring air quality. Some of these are fitted with integrated differential pressure measurement. Furthermore, additional probes, such as lux probes or probes for turbulence level measurement, can be attached to these versions.

Complex technology, but really easy handling

The testo 435-1 multi-function measuring instrument is characterized by an efficient measuring process which makes any inconvenient programming of the measuring instrument superfluous: probe-dependent menus and selectable user profiles for the typical applications of “duct measurement” and “IAQ measurement” ensure the easiest imaginable handling.

It also offers easy legibility due to its large display which has an illumination function. In addition, dew point distance, min., max. and mean values are displayed as well. A solid housing provides reliable protection against impacts for the testo 435-1 multi-function climate measuring instrument.

Documentation of measurement data on site

The testo fast printer, which is available as an option, means you can create a report printout of measurement data directly on site. For a duct measurement, you can for instance print out the current readings or the min./max. values for air velocity, volumetric flow, temperature and air humidity. You can use the printout as evidence of your work.

Use the practical cyclical printing function on the testo 435-1 as well. It not only enables the printout of individual readings, but also of whole series of measurements on the testo fast printer at freely adjustable intervals (for example once a minute).

We recommend you use the testo 435-2 or testo 435-4 versions for saving, documenting and archiving measurement data. They are equipped with a reading memory and PC software