Ever think about how powerful a cell phone is in 2014? They’re basically soap bar sized computers that we’ve become accustomed to doubling in performance every few years, capable of reliably streaming lots of data at very high speeds to an endless array of applications, no matter the location, for the purpose of making life easier and more productive (or to waste time depending on how you look at it). Cell phones are so ubiquitous that it is easy to overlook where their power really comes from: the underlying communication infrastructure they run on.
Developed and built from the ground up and in parallel to support the exponentially increasing data demands of the modern user, these networks have become as reliable, fast, and affordable as traditional wired networks. For example, the term "4G" is so pervasive that we associate it more with consumer cellular advertising than with wireless network speeds we would have called remarkable ten years ago. However, 4G is actually a wireless network capable of handling download/upload speeds approaching 10 to 12 Mbps. For comparison, that’s as fast as Cat 5 Ethernet. By 2020, the expectation is that these same 4G networks will be offering speeds up to 100 Mpbs, matching the speeds of Cat 5e.
So, where am I going with this? As control system engineers and process plant operators, we seem to be slower than most at accepting and adopting new technology. We inherently know that if something isn’t broken, than it doesn’t need to be fixed, and the systems we use today for our wireless communications, particularly radios, still do a fine job. Further, having watched cellular technology develop, there seems to be an industry wide aversion to the idea of using cellular networks because we have become accustomed to the idea that these networks have issues with reliability, security, and cost. That was true in 2000. It’s not true anymore.
The best example of how cellular networks are advancing controls engineering is through the use of wireless telemetry. Telemetry is the automated communication process by which measurements are made and other data are collected at remote or inaccessible sites and transmitted to receiving equipment for monitoring. Telemetry is an essential function of many utilities and process facilities, providing rich data that can be used for operations, energy management, cost containment, and regulatory compliance.
While cellular telemetry options have been available for some time, cellular companies have only recently begun offering machine-to-machine (also known as “M2M”) specific data services with dedicated hardware for use in the utility industry. These machine-to-machine systems have several advantages over traditional licensed radio: their infrastructure is maintained by the cellular provider; their data transmission rates are much higher resulting in improved performance; and their small size expands potential sites because of their discrete nature (it’s awfully hard to hide a 25 foot radio antenna required at a traditional poling site).
Additionally, the data traffic within these cellular networks is set up as a private network within the cellular provider’s system, ensuring the security of your communication. The best way to conceptualize these networks is as an extended Ethernet network, offering the same benefits, such as remote programming and diagnostics of remote terminal unit (RTU) equipment.
My hope in writing this article is that, as an industry, we can begin to accept cellular telemetry as a useful and viable option for wireless transmission of machine data because the benefits far outweigh the costs. A great way to test the water with cellular telemetry is to incorporate these technologies within an existing radio telemetry system. In most cases it is possible to install a cellular telemetry system in parallel with existing radio systems, allowing system operators to pick and choose certain sites within their system that need more reliable communication. Problem sites within an existing system using licensed radios or serial communications can be easily set up to communicate over Ethernet on a cellular network at the same time, allowing for redundant communications to important or problematic remote locations.
Cellular networks may have been developed over the years to optimize the wants and needs of consumers, but in this day and age the practical commercial application of this underutilized technology cannot be denied.