In a Control Engineering article, Emerson’s Andrew Cureton looks at several wireless protocols vying for greater adoption with industrial users.
There is immense hype around 5G these days. It will change our lives, we hear – but will it be an improved solution for industrial applications? It’s just one of the various wireless protocols trying to gain a foothold with process manufacturers, so how do they all relate, and which ones should you be paying attention to?
Trying to sort this out is the main point of my article on the cover of Control Engineering’s October issue. Wireless protocols are all designed to balance tradeoffs related to performance, including things like power consumption, range, available bandwidth, and so on. If you start analyzing the characteristics of a protocol, you can determine what is important to the uses for which it was designed. For example, WirelessHART is optimized specifically for wireless process instrumentation and field devices, such as Emerson’s Rosemount 3051 Wireless In-Line Pressure Transmitter, which is why it has been so successful for that purpose.
WirelessHART uses IEEE 802.15.4 radio technology with deterministic scheduling, plus frequency, temporal, and path diversity to achieve reliable, deterministic data transport using very little power. WirelessHART instruments have an expected 10-year battery life with update periods of 30 seconds and also supports low-latency downstream communications without sacrificing battery life, and it works with most existing handheld field devices to support calibration and diagnostics in the field. Its range is relatively short, but its self-organizing mesh technology can pass messages from one instrument to another, or via a repeater, to cover long distances or circumvent network disruptions.
WirelessHART does need to be supplemented by some other system to handle backhaul, the process of gathering data from gateways and access points and sending it to host systems and corporate networks. Sometimes the backhaul is wired using Ethernet or Modbus, but it can also be wireless via Wi-Fi. Emerson has partnered with Cisco to offer a newly-launched Wireless Access Point, which connects WirelessHART self-organizing networks to any host system using integrated Wi-Fi backhaul for the utmost in security, scalability, and data reliability. Now, 5G is also generating interest as a new possibility for that backhaul service.
5G looks like it offers possibilities to provide this critical backhaul function for individual plants or remote locations, enabling short- or long-range transmission of WirelessHART data to the cloud or a private network. Numerous gateways are already connected to cellular modems, enabling operational process monitoring and control, plus remote predictive maintenance of critical plant assets. 5G will improve this existing capability.
Time will tell how and where this technology catches on. At this point, 5G products and infrastructure deployment are still a work-in-progress. WirelessHART, on the other hand, is firmly established and thriving.
The outlook for HART and WirelessHART instrumentation remains strong as input/output (I/O) densities continue to increase with the size and complexity of new and existing facilities. Users appreciate its low-latency downstream communications, long battery life and the ability to work with most existing handheld field devices to support calibration and diagnostics in the field.
How extensively are wireless deployments in your plant? Part of everyday operation, or still in the experimental stage? Visit the Industrial Wireless Technology pages at Emerson.com for more on pervasive sensing, and evolving networking technologies and solutions. You can also connect and interact with other engineers in the Oil & Gas, Chemical, and IIoT & Digital Transformation Groups at the Emerson Exchange 365 community.