Published 2025-12-23

Digital sensors are becoming increasingly common in metrology. But what exactly is a digital sensor, how does it work and what are its practical benefits? Here we cover the basics.

What is a digital sensor?

A digital sensor is a sensor that measures, for example, temperature or humidity and sends the measured values as digital information to an instrument or a data logger. The sensor processes the measurement data itself and sends ready-to-use values, providing fast and reliable readings in the instrument. Analog sensors instead send a continuous current or voltage signal that the instrument must interpret.

Why do digital sensors provide better accuracy?

What makes digital sensors particularly accurate is that both the measurement and the interpretation take place in the sensor. With analog sensors, accuracy is determined by both the instrument and the sensor, and measurement data can be affected by electrical noise or voltage drops on the way to the instrument before the signal is interpreted. Because digital sensors send ready-to-use values, measurements remain stable all the way from sensor to instrument.

Digital technology also allows for higher resolution, often with more decimal places. The result is more reliable and comparable measurements, reducing the need to re-measure.

What are the main benefits of digital sensors?

• Easy integration and more stable measurement
  The instrument automatically recognizes the sensor type and receives ready-to-use measurement values directly. This provides higher accuracy and reduces the risk of both misalignment and incorrect readings.
  
  
• Flexibility
  Digital transducers can be seamlessly integrated into instruments and measurement systems that support different transducer types or multiple measurement channels. Most of Testo’s digital transducers use the same type of connector, making it easy to connect and switch between different transducer types in the same instrument.
  
  
• Easy identification
  Digital sensors have unique serial numbers, which simplifies tracking and management of the measuring equipment. Each transducer is calibrated as a separate unit and has its own calibration document (easily accessed by scanning a QR code on the transducer once it has been calibrated with us).
  
  
• Calibrate without pausing measurements
  Since digital sensors are calibrated separately, you can send the sensor for calibration without having to send the entire instrument. Therefore, by replacing the sensor, you can continue your measurements even when a sensor needs calibration.
  
  
  

Measuring instruments for digital sensors

Published 2024-11-22

Setting up ventilation is important to ensure a good indoor climate and to keep operating costs down. But, as many of us know, it is often a time-consuming process, especially when it comes to large systems where several technicians often have to work together to measure flow and pressure several times in different places in the buildings to achieve optimal ventilation adjustment.

Thanks to the Celsicom V600, these problems are a thing of the past. In fact, with the help of the meter, a ventilation technician can perform really big adjustment jobs all by himself.

Adjustment of ventilation with Celsicom V600

All you need to set airflows in a system is our new tuning instrument, an optional airflow meter and a mobile phone or tablet. Here is our step-by-step guide to setting up ventilation with the Celsicom V600:

• Remove the sliding cover of the Celsicom V600 and scan the QR code inside with a mobile/tablet
• Create an account on the Celsiview cloud service webpage that appears on the screen
• Add the Celsicom V600 and choose the instrument for your measurement
• Identify the weakest point of the ventilation system, i.e. your reference device
• Enter the K-factor and projected value for reference actuators and other actuators
• Connect the calibration instrument to the reference device and the measurement is underway.
• Celsicom V600 guides you through the entire proportional adjustment process
• The mobile/tablet displays the current adjustment values for each sensor
• If a pressure change occurs in the system, new values are calculated – in seconds!
• Finally, raise or lower the reference actuator to 100% (as designed) and the values of the other actuators will be automatically adjusted

“No need to go back and check measurements”

This is how ventilation adjustment works with Celsicom V600. One person who has discovered the advantages of the new adjustment instrument is ventilation technician Tor Halvorsen at VXPro AB. Tor has used the instrument for several large adjustment jobs and believes that it facilitates and improves his job in several respects.

– I don’t have to spend time doing my own calculations, nor do I have to go back and check the reference device. In the past, it often took at least three trips to get all the values right. Now I get it right straight away,” says Tor, adding that the Celsicom instrument makes him more efficient.

– It saves at least a third of the time. Up to half in some cases. Depending on the accessibility and complexity of the systems.

Impressively accurate alignment

In addition to the time savings, the Celsicom V600 and Celsiview allow Tor to perform large adjustments with impressive precision. He often exceeds the requirement of six percent accuracy in the adjustment between the sensors by far.

– “I often get down to three percent accuracy, which benefits everyone. The tenants get a comfortable indoor climate and the property owners lower energy consumption,” says Tor Halvorsen, who sees how the smart measuring instrument allows him to “do more in less time”.

– This is a great solution that gives me more capacity every day of the week!

Discover other Celsicom meter boxes

The Celsicom product family also offers measurement boxes for accurate measurement and analysis of other quantities such as temperature, humidity and differential pressure to ensure safe and optimal environments in many different industries.

Companies operating in sectors such as construction, real estate, moisture damage management and the food industry benefit greatly from Celsicom’s flexible and precise measurement boxes. Whether you need to ensure indoor air quality, monitor workplace conditions or meet critical environmental parameters, Celsicom can help you do so with the highest accuracy and reliability.

Curious about the user-friendly, reliable and versatile Celsicom? Read more here!

Published 2025-09-22

Ventilation technician Tor Halvorsen uses Celsicom V600 reference sound level meters for ventilation adjustment.

Med över 20 års erfarenhet i branschen vet ventilationstekniker Tor Halvorsen vikten av pålitlig mätutrustning för effektiva injusteringar. Sedan drygt ett år använder han Celsicom V600. Resultaten har varit otvetydiga: mindre tidsåtgång och precisare luftflöden, jämnare drifter och betydande energibesparingar.

Tor Halvorsen and his colleague Patrik Pålsson at VXPro AB specialize in ventilation adjustments in all types of properties. Everything from homes belonging to small and large housing associations to commercial premises and offices in properties of all sizes.
– When we work for housing associations, it can be from twenty to several hundred apartments with three to seven measuring points per apartment. For example, in a residential area with 300 apartments, there may be an average of around 1,500 air diffusers. In addition, there are public spaces such as laundry rooms and community halls. So it’s important to work smart with ventilation adjustment,” says Tor Halvorsen.

Traditional tuning – time consuming and outdated values

Traditional tuning means that the reference sensor is measured repeatedly during the tuning of the other sensors. This is necessary to see the current ratio (the relationship between the current value and the target value) to adjust against. The ventilation technician then has to go back to the reference device often, usually three times – sometimes up to six or seven times, to check it. After a while, it becomes uneconomical to go back to the reference device after each throttling. If control measurements are not taken, the result is that the current quota is not always available.
The solution to avoid time-consuming control measurements and minimize adjustment errors is real-time reading of the current ratio. With traditional tuning, real-time reading can only be achieved by a technician continuously measuring the reference actuator and communicating the new ratio via radio or telephone to the colleague throttling the actuators.

Celsiview cloud service – real-time reading with Celsicom V600 for fast and more precise ventilation adjustment.

Averaging is the key

Many measurement solutions for real-time readings consist of reference dosimeters connected via radio or Bluetooth (with limited range) and a base station and modem. The Celsicom V600 consists of a single unit: a compact, battery-powered reference densitometer.
After the meter automatically connects to the mobile network, the ventilation technician continues his work in the web-based Celsiview cloud service on a mobile or tablet. The screen displays the current values of the reference actuator and guides the technician through the adjustment of all actuators.
– Thanks to the Celsicom V600 averaging, I can see immediately if the values are within the right range. I can easily see fluctuations in pressure and use the average instead. This means I can often get the difference down to two or three percent, which is more accurate than the normal method error of six percent,” says Tor.

“Small and flexible measurement solution”

Tor previously used Celsivent, the predecessor of the Celsicom V600. He was quickly impressed by the new model:
– The V600 is a small and handy measurement solution. Apart from the meter itself, all you need are batteries and measuring hoses, an optional airflow or pressure gauge, and your regular mobile phone or tablet. It starts up and connects quickly. After a few minutes, you are ready to start measuring.

Tor also appreciates a number of small but important details that make his job easier. These include the magnetic bracket and the measuring hook that allow Tor to easily and safely connect the V600 to supply air and exhaust air devices.
– I also like the fact that the battery status is clearly displayed on the tablet, so I don’t have any unpleasant surprises. The operating time is also really good. I can often measure for several days without having to change the batteries in the V600, which is powered by standard AA lithium batteries.

Emergency jobs cleared quickly

Tor and his colleague Patrik recently got a clear proof of the benefits of Celsicom V600 during a job on the island of Öckerö outside Gothenburg. At short notice, they responded urgently and made adjustments in two properties with a total of 18 apartments.
– We expected to spend eight hours, but finished in five. And that’s despite the fact that the installation wasn’t finished when we arrived. We even had to help the electricians with the control technology to get the fans going,” says Tor and adds:
– “It was good for us to once again get confirmation of how well the Celsicom meter works. The adjustment itself took about three to four hours, which is also three times faster than traditional ventilation adjustment!
No wonder that Celsicom V600 has become an obvious work tool for Halvorsen and Pålsson at VXPro AB.
– Everyone I have recommended it to is happy. It is an invaluable tool for anyone working with ventilation adjustments.

Published 2024-06-25

Since 2016, energy engineer Billy Axelsson has been using data loggers from the Celsicom measurement system to remotely monitor various indoor climates in Kil municipality’s buildings. The loggers enable more efficient work and reduce energy consumption and the risk of costly breakdowns.

Billy Axelsson works at the property unit with responsibility for energy and ventilation. It is a small job considering that the municipality operates on about 60,000 square meters in about 50 buildings. These buildings house commercial kitchens, schools, nurseries, leisure facilities, care homes – and a range of other businesses.

An important part of the real estate unit’s work consists of remote monitoring of various climate parameters in different environments, in order to analyze important measurements on a daily basis and schedule measures or, if necessary, respond immediately. Measured variables such as temperature and humidity are monitored with data loggers from the first generation of the Celsicom measurement system (the loggers are connected to base stations) and data loggers from the second generation of the same system (these loggers have their own connection via the Narrow Band Internet of Things on their own frequency in the mobile phone network). In total, there are 107 measurement sites in 27 buildings.

Celsicom – an important backup
The fact that Celsicom was chosen eight years ago was mostly a coincidence.

– We have some comprehensive systems for monitoring and controlling heating and ventilation in our buildings. But I felt the need to have some kind of backup to be able to have continuous control and get alerts. “At one point I bought a thermal imaging camera from Nordtec and was a bit curious about what other fun things you had,” says Billy.

That’s when he discovered and chose to test Celsicom. Since day one, the remote monitoring system has greatly facilitated the work of the real estate unit. Above all, the ease of getting started and using the Celsicom logs is appreciated. The automatic limit alerts via SMS or email are also praised. And the fact that the purchase of each logger – including the subscription cost for storage and analysis in the Celsiview cloud service – is a modest investment.

Automatically alerts in good time
The real estate unit has found a variety of applications for the Celsicom loggers. Here are some examples of what they are used for.

– If a chiller breaks down or starts leaking refrigerant, the chiller can continue to run while the temperature starts to rise. This can quickly be seen from diagrams in Celsiview.

– Another great advantage is the possibility of receiving an alarm if, for example, a large meat fridge breaks down. Then you have to act quickly to avoid having to throw away goods worth SEK 100,000 the next day.

Celsicom loggers are also used in schools to ensure a good indoor climate in classrooms, to monitor temperature and humidity in music rooms and to prevent damage to stringed instruments. The remote monitoring also covers four pellet plants. There, Celsicom loggers simply alert you if pellet levels are approaching a critical level and it’s time to refill.

Preventing an expensive mishap
– I have also made a little invention of my own with one of the latest Celsicom loggers that has moisture ratio sensors (Celsicom MM611B). I’ve connected it to a screw in a wooden plank lying on the floor of a basement where we have very little supervision. And last winter there was a water leak from the heating system! I was alerted within an hour that the moisture content was too high in the wooden plank and was able to go there to quickly fix the flood and leak. It could have been really expensive if I hadn’t had that monitoring,” says Billy.

Celsicom also eliminates time spent traveling around checking conditions in different properties.

– Instead, I always have updated readings via the Celsiview cloud service on the home page of my computer. I can quickly see if something seems strange and can easily see how things are developing, and then decide whether I or someone else needs to go to the scene.

Good information and data
Celsiview is also a good tool for sharing information and providing input for various improvements. For example, staff in commercial kitchens can log in and have a ‘watch’ function to check temperatures in cold rooms and freezers in real time for their own control.

One of the property unit’s major challenges in the future is to make operations more efficient by, for example, reducing electricity and district heating. It’s about reducing energy use as much as possible without sacrificing a comfortable indoor climate. In this respect too, deployed Celsicom loggers are valuable tools.

– It is very easy to quickly see on your mobile phone, tablet or computer where the temperature is a bit too high and can be turned down to reduce heating costs. “In an electrically heated school that is in storage, I have Celsicom connected to the heating system to be able to keep the temperature as low as possible without it freezing in the winter,” says Billy Axelsson and notes:

– We save a lot of money by having sensors monitoring the radiator groups.

Published 2022-08-11

Operation technician Martin Lundin works with the indoor climate at the hospital in Västerås but also at the hospitals in Fagersta, Sala and Köping in Region Västmanland. His constant challenge is to create comfortable indoor environments for both healthcare professionals and patients while keeping energy consumption low.

To help him in his daily work, Martin Lundin often uses the smart multi-instrument testo 400. Nordtec caught up with Martin to hear about his impressions and experiences with this climate meter.

Can you tell us a bit about your work?
– I do everything in the field of indoor climate and check ventilation flows and also perform some minor adjustments. However, as we have about 400 000 square meters to cover in our premises, much of this work is done by hired contractors.

– I am also an energy coordinator. In this role, I work actively to reduce energy consumption, which is measured in kilowatt hours per square meter.

– Also, you should not feel that there are temperature differences between different hospital departments, but it can be difficult to find that balance. However, the instrument is great for walking around and measuring temperatures and also differential pressure between different corridors, i.e., the air conditioning system. over- or under-pressure to ensure the right balance of ventilation systems.

– I also work on preventive maintenance. To enable my staff to easily troubleshoot when we have problems with heating or ventilation, I have equipped them with a bag containing the testo 440 multi-instrument and various accessories. Good work always requires good instruments and tools.

Do you measure both in premises and ventilation ducts?
– Yes, exactly. I measure temperature, humidity and airflow in ducts and premises. When measuring flow in canals, I sometimes have to drill a hole and measure at several points in a cross section of the canal area.

You mean so-called grid measurement?
– Yes, that’s right. That’s where the instrument is fantastic. You specify whether it is a square channel, for example, enter the dimensions and then take a number of measurement points. The instrument then automatically calculates the airflow.

Are you satisfied with the instrument?
– I’m super happy. I had a testo 440 dP before, but needed an instrument with better pressure measurement accuracy and the ability to log trends. There are so many more possibilities with the testo 400.

Do you feel unfamiliar with a touch screen on a measuring instrument?
– No, given today’s technology and how accustomed we are to mobile phones, it was quite natural. On the contrary, it was very easy to get started with the testo 400.

How do you analyze the measurement results?
– I usually connect the instrument to the computer and use the program testo DataControl to analyze the values. Then I get reports that are very useful where I can also attach pictures. I think that’s really good.

Can you tell us about a particularly interesting measurement mission?
– Yes, in Sala hospital we changed the control equipment on an old unit to get better control of the supply air temperature. But initially there was too much alternation between high and low temperatures.

– Then we were able to use the 400, because we could connect both before and after the heating coil. The controller’s P and I times were changed and we could continuously see how it calmed down or if the values jumped. You could see when it started to oscillate. That’s where the trend management in testo 400 is fantastic.

– Then I am currently working on mapping the indoor temperatures of the entire hospital, in all departments at different outdoor temperatures.

That sounds like a big job?
– Yes, our client requires that energy consumption be reduced, so we have a huge job ahead of us to get the right curves, especially on the heating side and to have the right temperature in the supply air.

What did you use before getting the testo 400?
– Previously, as I said, I had a testo 440. But I needed better accuracy of the differential pressure measurement at low air flows. Also, I like to see trends, which cannot be done in the same way with this instrument.

What kind of sensors do you use?
– I have a small hot wire sensor that is always in the instrument. Then I have a digital sensor that measures both moisture and temperature. These values are transmitted to the instrument via Bluetooth. Both these sensors also work with the old testo 440. Then I have a clamp-on sensor for pipe temperature measurement as well.

What did you use before getting the testo 400?
– Previously, as I said, I had a testo 440. But I needed better accuracy of the differential pressure measurement at low air flows. Also, I like to see trends, which cannot be done in the same way with this instrument.

Have you needed support from us to get started?
– No, I think it has worked well. The only thing that happened was that the pipe temperature sensor broke on one occasion.

Do you also use data loggers to see trends over time?
– Yes, I do if I am unsure and there are major problems that are not immediately apparent. Then I have to log for a longer period of time and analyze the anomalous trends afterwards.

Do you have any requests, anything you would like to see in the instrument?

– I don’t know… I haven’t used exactly all the features yet, but right now I’m just very happy with the instrument!

– If one could wish freely, it would have been good to have a socket at the top of the front for a hot wire sensor. He often holds the instrument upside down.

– Then it would be good if you could make a few more pre-settings in the instrument via the analysis program testo DataControl.

Published 2022-08-10

Almost ten years ago, Johannes Öberg switched from being a shop salesman to a service technician in ventilation. He hasn’t regretted it for a second. We caught up with Johannes to talk about the varied challenges of the job, ‘airborne’ and his love of testo 400.

– I like this job because no two days are the same. “There are always different conditions and challenges that must be solved to ensure good ventilation and a comfortable indoor climate,” says Johannes Öberg, who is currently a ventilation technician at Bravida.

An example of this is when Johannes and his colleagues were hired to review the ventilation system of a tire company. The unit was old, but even old units can last for many years. If they are maintained at regular intervals, that is. This unit had received minimal love over the past eight years.

“The air did not get through”
– One of the fans tripped because of the overheating protection and we had to do an extensive cleaning and filter replacement. They were so dirty that the filter bags had started to come off the frame. The air was simply not getting through. ‘It was like trying to draw air through a plywood sheet,’ Johannes recalls and continues:

– Of course, it took some time to fix everything. And time, as we all know, is money. But the people working there have to have air and that unit hadn’t delivered any air for years. It had just stood and walked with a single working fan.

This is what Johannes likes about his job. He enjoys tackling something that is a bit tricky, thinking about it a few times and then coming up with a solution. It is far from easy all the time, because every site is different. From belt-driven fan systems from the early 1970s to the very latest advanced ventilation systems with different layers of control systems.

Factors affecting air quality
Johannes and his colleagues are often called out on emergency missions. Often the complaint is that it is too hot in a room. While it may be that the ventilation system is not doing its job, it is remarkably often the case that other factors affect the perceived air quality.

– One room may have been converted into a conference room and more people are staying there than before, which affects the air. It can also be about a light source that makes the room warm. Sometimes it’s a bit difficult to determine whether it’s hot air or stuffy air. If it’s just stuffy air, it often means that we have to fix the ventilation. But if it is too hot, it is more likely to be due to the cooling or heating system.

A common ‘air villain’ is dust. Air ducts that have not been cleaned for a long time can accumulate up to one centimeter of dust, which reduces the diameter of the pipes quite significantly. This creates annoying additional noise and also results in lower air flows.

“The pipes are roaring”
When we meet Johannes, he and his colleagues are busy finishing the rebuilding of the ventilation system in the roofing company Wicote’s premises in Arendal, just outside Gothenburg.

It is a relatively old facility that has looked the same for many years, even though the premises have been redesigned several times to suit different tenants. The challenge was to find a good ventilation solution without rebuilding everything. There is nothing wrong with the unit and the airflow is there. Instead, it has involved, for example, adding supply air ducts where necessary.

– There is noise in the pipes, which is a sign that the unit is running too hard and pushing out too much air. During the adjustment, we will open all the valves fully and measure the total flow.

– By adding up all the sub-flows, we know that it should be a total of 330 liters. We put the aggregate at about ten percent above that to have a bit more to work with. We will then go around measuring and adjusting the devices, and then turn down the fans if necessary.

You use testo 400 exclusively, why?
– For several years I have used almost exclusively Testo instruments. This is largely because several other manufacturers have designs and user interfaces that feel very dated.

– One thing I like about the testo 400, for example, is when measuring with hot wire in a channel. The graph then guides me through the measurement. “If I set up twelve measuring points, for example, the meter tells me to insert the probe nine millimeters into this borehole, it then registers the result and I can move on to the next measuring point,” says Johannes, who points to the instrument’s large touch screen and then adds:

– The 400 is also particularly good if you are measuring a duct that has a touch screen. Then you just hold the hot wire sensor against the cover to measure.

Easy for everyone to use
Johannes points out several times that he appreciates the simplicity of the testo 400. Since he uses the instrument daily, he has quickly learned how it works. But it works just as well if a colleague needs to borrow it to measure the flow in a channel, for example.

– We have compared and seen that it works without problems. I have first made a measurement, handed the instrument to a colleague who made his own measurement and then compared the results. Especially hot wire measurement is very sensitive, because if you tilt the sensor towards the air stream a little bit, you get a completely different value. But by being guided through the measurement, both I and my colleagues got the same results.

– The instrument is a great help for those who are reasonably experienced and fantastic for those who are less experienced.

Create and send reports
The instrument’s built-in camera and report function is something that Johannes really likes and uses a lot.

– It’s great to be able to create detailed, attractive reports directly in the tool and then email them to customers. With the built-in camera, I can take pictures that show, for example, the position of the damper during the measurement. It shows which sensor was used and the differential pressure and airflow.

In addition to attaching pictures, there is the possibility for Johannes to easily enter text explaining what he has done, thus avoiding discussions about the number of working hours and costs for e.g. service with filter replacement. Johannes Öberg believes that it is this simplicity and all the smart functions that make the testo 400 an extraordinary measuring instrument.