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Factories and the challenge of wireless networks

Radio noise and big metal machines are just some of the factors making it difficult to build a strong Wi-Fi network in a factory.

Engineering a good wireless network is a difficult task as it is, but few environments are as consistently challenging as factories.

Industrial Wi-Fi refers to all manner of wireless communications on the manufacturing floor—from the damp and steamy realms of papermaking to the twisted mazes of piping and conduit in oil and gas plants. Industrial airspace is one of the hardest environments to conquer.

Expert professional services are a requirement if you want your factory to run optimally and with a minimum of downtime. Here is why industrial Wi-Fi is different, some of the problems that are common, and some of the ways to work around them.

Machinery impedes signal

The environment of the typical indoor facility is filled with a variety of machinery, most of which is designed for whatever the site produces. These machines are all metal and steel; some are pressure-driven, while some are electrical. This creates an incredibly hostile world for wireless communications.

With all this metal, reflectivity, diffraction, and scattering of the wireless signal become complicated problems. Unfortunately, issues like these do not usually show up on a standard passive scanning assessment with tools like NetAlly's AirMagnet or Ekahau's Survey Pro.

Now, to address a common misconception, when we mention industrial wireless, images of warehouses and lines of giant shelves with forklifts cruising around usually come to mind. This is known as warehouse Wi-Fi. While warehouse Wi-Fi has its own set of challenges and idiosyncrasies, it is not industrial Wi-Fi. The only similarity some manufacturing plants may have with warehouses are the buildings in which they are housed; that's where most similarities end.

In the industrial world, non-Wi-Fi interference from machinery is a much larger complication than it is elsewhere. Different types of machinery can produce radio frequency (RF) activity that is not structured by any sort of communication protocol. Essentially, it is just noise in the RF spectrum.

Think of it like this: Two neighbors are having a casual conversation in one of their driveways. They are speaking at normal voice levels and effectively communicating with one another. A third neighbor pulls up on his riding lawnmower. It is so loud that the first two neighbors now cannot hear each other and effectively converse. The sound is overpowering their voices, but it is just sound with no communications structure or value to it. In this example, the source of interference is obvious, but many times the sources can be difficult to track down and identify. This just adds to the challenge of successful wireless deployments in the industrial and manufacturing airspace.

Like other common kinds of wireless deployments, there can be a fair amount of Wi-Fi base interference as well. Unfortunately, many equipment vendors that come into a facility to install their machinery will install their own wireless access points and not mention this to the new owners. Some vendors go so far as to implement their own extended wireless networks around multiple pieces of equipment and may or may not tell the client of their existence.

Printers installed in control rooms and other locations usually have their Wi-Fi left on by default, while users just plug them into their machines via USB cables and forget about it. Employees around the sites continuously run Wi-Fi hotspots on their personal devices. I recall in one survey I did at a paper mill, while standing in a spot roughly central to the mill grounds, I opened a simple Wi-Fi scanner on my smartphone and counted more than 40 unique service set identifiers (SSIDs) or signal names. In a normal office setting, you might reasonably assume that IT is in on making the decisions about networking, but this is frequently not the case in a factory.

Environmental challenges

The physical conditions in manufacturing environments also play a role in the challenges of wireless deployments. While some facilities are temperature controlled and relatively clean, most are not. Many sites are continuously very hot. Some combine that heat with excessive dust or moisture—think very high humidity. Others may have mildly corrosive gasses or liquids that over time eat away at cabling or casings. All these examples are detrimental to sensitive electronics in general.

With all the environmental variables, it is no wonder that standard wireless access points and other radio devices do not last long. In some situations, standard equipment can be used out in the open like any other deployment. In the more extreme cases, though, radios either need to be put into special NEMA-rated enclosures or special ruggedized gear must be used.

Ruggedized radios tend to be more expensive than their standard counterparts; however, they are built to withstand these harsh environments. Commonly the casings are made of metal or high-temperature-resistant plastics. All seams, antenna connections, and data ports are well sealed to keep out moisture and dust. These devices usually have an Ingress Protection rating of IP66 or IP67, meaning they are completely sealed against the elements.

Priorities in the factory

Finally, when wireless communications become an essential part of an operational technology (OT) network, you are no longer playing by the rules of a standard IT network. In the realm of IT, networks run on what is known as the CIA triad: confidentiality, integrity, and availability. These points are of top priority for data protection and viability.

Wireless systems can be rebooted and modified as needed, generally with little warning to the end users. In OT, the priorities are different, following what is known as the SRP triad: safety, reliability, and productivity. This translates into not being able to take down equipment whenever someone wants to upgrade firmware or perform a maintenance reboot. Anything that stops the process or production cycle is very bad, not only from a financial perspective but, more important, a safety one. If an integral part of a production process involves wireless communication and those devices are taken offline abruptly, it can cause improper shutdowns, which can conceivably cause mechanical damage and threaten the safety of workers. Of course, these rules run counter to other best practices, such as applying security updates promptly.

This has been only an overview, to convey how different things are when designing and implementing wireless networks in an industrial environment. Every location is unique, and there are special standards used in industrial wireless that are uncommon in warehouses or for office Wi-Fi. If you are responsible for wireless networking in an industrial environment, you should be aware of the special challenges and make sure to investigate them.

Lessons for leaders

  • In an industrial environment, wireless networks become part of operational technology and must be accessible and reliable.
  • In the industrial world, different types of machinery can produce radio frequency activity that is, effectively, just noise in the RF spectrum.
  • Industrial Wi-Fi is a specialized field for which conventional Wi-Fi experience is likely inadequate.

Related stories:

Why shadow IT is a risky bet for OT departments

Designing future refineries with Industrial IoT

What is the Industrial Internet of Things?

This article/content was written by the individual writer identified and does not necessarily reflect the view of Hewlett Packard Enterprise Company.