Wireless connectivity will play a very large role in the future of the Industrial Internet of Things (IIoT). However, at the point where the technology is currently being used in industrial automation, you’ll see very little sign of it except for the occasional Bluetooth device or 3G/4G access point in remote installations. Nevertheless, there’s a large existing foundation of wired interconnectivity that can be built upon to move today’s systems toward a true IIoT experience.
While the consumer wireless world keeps expanding, major challenges await the expansion of wireless connectivity in the industrial world. Right now, there are two primary standards that are well positioned for expansion: Bluetooth and 802.11 Wi-Fi. Both use similar frequencies in the 2.4 GHz band plus some versions of Wi-Fi can also use the 5 GHz band. Unfortunately, for both standards, signals at these frequencies are strongly attenuated by objects in the signal path. Metal objects, which are very common in industrial settings, are particularly troublesome in this respect. The results are short transmission distances and poor signal stability, which are two important factors in the current lack of uptake of wireless systems.
Another challenge is that, in many of the components that are crucial for the wider adoption of IIoT, there is a need for reliable ultra-low power wireless connectivity. This isn’t as much of a challenge when considering components like AC drives that are connected to the grid and have plenty of power available for a built-in wireless module. But, on the wireless sensor side, the challenge is much more significant. There are low-power versions of Bluetooth and Wi-Fi as well as other well-known low-power connectivity standards like ZigBee, but since they all still utilize the 2.4 GHz and/or 5 GHz bands, they don’t have the capability to transmit reliably through obstructions.
Further, as the number of wireless transmitting devices increases, the wireless environment becomes increasingly congested. This can result in two or more devices sharing the same frequency and channel at the same time, leading to lost packets or other transmission failures. Security is also a concern, as any device broadcasting a wireless connection is a potential intrusion point. This means that suppliers of components for use at every level, from the control system right out to the facility network, must adopt robust security measures.
Solutions are on the horizon
Fortunately, solutions to these challenges are on the horizon. As wireless connectivity grows, there will be a greater emphasis on providing things like sensors with more localized intelligence. Star networks will largely be abandoned, and instead the focus will shift to highly flexible mesh networks that will provide much higher network reliability and communication efficiency. Mesh networks also have the benefit of transmitting around transmission obstructions, which perfectly suits industrial environments. There will likely also be a longer-term move to new frequency spectrums below 1 GHz that provide a better balance between transmission distance, throughput and power requirements, but this is, at best, speculative.
What does all this mean to the reader? Well, the honest answer at this point is “Not much.” Simply having a wireless network isn’t enough, especially with no standardization of technology or communication methodology likely in the near future. At some stage, however, a critical point will be reached that requires the setting of an ‘interconnection foundation’ to ensure that all devices with wireless connectivity can talk not only to the primary controller, but also to each other. The result might be a standardized IIoT module or chipset, an IIoT operating system, or an IIoT architecture along the lines of an API that can be integrated into management tools to ensure interconnectivity.
It will be this intersection of IIoT standardization, security and availability of technology that will truly be the inflection point toward the future of industrial automation.
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Author: Jake Roeder, Global Product Marketing Manager, Danfoss Drives