Does wireless beat wired in building automation measurement and control systems? It depends on the client’s needs.

Wireless systems are rapidly gaining ground in the building automation sector. Their growing popularity is explained by both the global IoT megatrend and the vastly changed requirements in the energy efficiency and spatial adaptations of facilities over the last decades.

Clients often ask me about when and what kind of wireless is the best option for them. They wonder whether they should choose wireless over wired, and whether all wireless systems are comprehensive or reliable enough. Today we don’t yet have a wireless system that would fulfil all the multiple requirements, but options abound for many different purposes. The best candidate will be found once the salesperson discovers and understands the client’s needs. When selecting a measurement and control system for building automation, it’s always worth consulting a professional and considering the issues I’ve listed below.

A common concern for clients is how network topology affects the viability of the solution. The full potential of a mesh network, for example, is lost when the number of measurements points is low or the transmitters are located far apart. In such circumstances, the extended range created by multiple transmitters is lost, so a point to point network with more limited technical features may be a better solution.

What will be measured and how accurately?

Naturally, one of the key criteria for choosing a measurement solution is what the client wants the system to achieve. How accurate and reliable do the measurements need to be, what is measured and how often, and how many measurement points will be installed?

If the sensors are expected to deliver reliable information about fluctuations in the environment rather than just sending measurements at certain intervals, it is crucial to select transmitters with high quality components and smart functionalities.

The less costly IoT sensors are often meant for approximate measurements, and they can’t be expected to deliver fully reliable information about prevailing conditions. Ballpark figures from a few measurement points are in no way comparable to a reliable, scalable measurement system that has undergone a strict quality control process.

How future-proof and ecological should the solution be?

Is the idea to use the system through the entire lifecycle of the building or the building automation system or will it be replaced as requirements change? Building users’ needs regarding comfort, functionality and scalability evolve continually, and a wireless measurement system allows the owner to adapt facilities without making costly changes to the building automation system. There’s no need to consider moving or installing cables, as it’s enough to buy new sensors or transfer existing ones to new locations.

Investing in a reputable supplier’s wireless system is an easy way to ensure the availability of support, updates and new functionalities, which will further lengthen the lifecycle of the solution. Even big name solutions, however, are not ecological and future-proof by guarantee. For starters, I recommend checking a simple but important feature, which shouldn’t be taken at face value for lower cost sensors: can the batteries be changed? If not, a fully functioning sensor must be thrown away as soon as its batteries run out.

Is cabling even possible?

Wireless doesn’t need to replace wired completely, but it provides an alternative should cabling not be desirable or even possible. For historic or listed buildings, for example, running and routing cables is usually out of the question.

In certain circumstances existing cables can even become part of the wireless solution. We have, for instance, repurposed the cabling for an old, passive temperature measurement solution to 24 volt feeder cables for wireless temperature, humidity and carbon dioxide sensors. While wireless has taken over from bus cabling, the old cables now power the sensors to eliminate future worries about battery replacements.

How and why is data collected?

Will the measurement system be integrated into the cloud purely to gather data, will it be directly connected to a local automation system in charge of controlling the building’s environment, or would a combination of the two make the most sense? Will an external provider deliver the data as a package charged by the month, or is it preferable to keep the entire system within the building?

Both the traditional, locally operated systems and the new, often operator-based wireless systems have their benefits and disadvantages. Solutions linked to the building’s own automation system, frequently designed for professional use, aren’t dependent on external factors such as internet connectivity or operator disruptions. Such a wireless system is also easier to adapt and scale. An operator-based wireless system comes into its own when the goal is to analyse and collect data about a building’s environment without establishing a local wireless network.

Reliability first

If I tried to answer every possible question about wireless, I could go on forever. Though a wireless system is just one of many ways to transfer data from one place to another, it should no longer be dismissed as a mere emergency solution for when someone forgot to install cables. Traditional wired systems can usually be depended on for two decades, until the next renovation project. Wireless measurement solutions, however, offer a solution for more and more projects, for instance when the aim is to improve the energy efficiency of an existing built environment or to ensure the comfort of a building with room-specific measurements.

Produal has played a part in improving indoor air quality for more than 30 years, with wired and wireless measurements alike. As a solution-focused provider, we want to offer our clients high quality products that help them complete the most challenging installation projects successfully and provide seamless access to data. This is embodies in our motto, ’Measure – be sure’, which guides everything we do, now and in the future.

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Antti Salli
Product manager, transmitters and wireless products

Building automation professional with a practical and design level passion for today’s and tomorrow’s building automation solutions.