With the coming of the IIoT and the whole discussion of the “connected enterprise,” process manufacturers may think, “Hey, we’ve always been connected. What’s the big deal?” What they discovered is the difference between connecting a pressure transmitter to the I/O card of a DCS using a 4-20 mA signal is vastly different than the kind of connectivity imagined with the IIoT.
Dan Carlson looks at the real-world implications of this situation in his article in the November 2018 issue of IIoT for Engineers, Bring IIoT capabilities to Refineries and Process Plants. Those field instruments connected via dumb analog I/O to an old DCS platform might just as well be unconnected, at least as far as IIoT technology is concerned.
The Internet in and of itself connotes wireless Ethernet such as Wi-Fi, but process industry complexes have enormous populations of field instruments and actuators using analog and digital fieldbus communication. Wi-Fi has not been adopted for these devices and there are no signs of a change in that direction.
So if Wi-Fi enabled instrumentation isn’t an option, and it isn’t, how is it possible to interface IP-based communication with instrumentation? Dan offers a very practical alternative: WirelessHART.
What has happened is the adoption of wireless communication for device-level networks. The leading protocol for this purpose is WirelessHART, which has grown steadily in hardware availability and deployments since its first release in 2007, and its adoption as global standard IEC 62591 in 2010.
The user case/benefit that has driven adoption of WirelessHART more than any other is its cost compared with traditional wired alternatives. As Dan points out, the cost of adding a wired instrument in a refinery typically falls between $5000 and $50,000. But are potentially boom-able plants really using wireless? Yes, they are, but adoption requires an appropriate level of examination and planning.
The heavy refining and petrochemical industries don’t adopt new technologies on a whim, even if promised a cost reduction of 75%. Given the potential harmful consequences of a bad decision related to something as complex as the Industrial Internet of Things (IIoT), or even WirelessHART, it must be reviewed extensively beforehand. Internal teams try to think through the risks and the pros, and cons of a new technology. They consider where appropriate applications can and should be used, along with areas where they should be avoided.
Dan examines the thought process used by many of these companies to determine when and how to use WirelessHART instruments. While refineries and similar plants are necessarily conservative and cautious, many have been quick to embrace wireless. The article goes into some depth on how plants select applications, and how they arrange the backhaul networks for reliable service. Give the full article a read and you’ll pick up some pointers. Suffice it to say, WirelessHART is supporting applications such as Plantweb Insight, that its designers could not have imagined, even 10 years ago.
DCSs and asset management platforms tended to be large and monolithic but are now supplemented and replaced by smaller, less overhead-intensive systems using mobile devices and the cloud. For example, the mechanical condition of a centrifugal pump installation can be checked via a smartphone app. The app can reach back through the plant networks and gateway to the WirelessHART diagnostic sensors installed on motors and pumps.
You can find more information like this and meet with other people looking at the same kinds of situations in the Emerson Exchange365 community. It’s a place where you can communicate and exchange information with experts and peers in all sorts of industries around the world. Look for the WirelessHART and IIoT Groups and other specialty areas for suggestions and answers.
Posted by Deanna Johnson, Rosemount Measurement & Analytical Global Marcom Manager, Emerson Automation Solutions