In January VDC Research Group (Natick, MA) published a study entitled “2010 Industrial Networking Infrastructure Products Global Market Requirements and Opportunities Analysis,” which took a look at the key trends expected to shape the 2011 industrial networking solutions market and made predictions of the rate at which the market would expand. While the study covered both wired and wireless networks, this article will concentrate on the wireless area.
In that area, the study predicted that, “[a]fter years of unfulfilled hype and hope, the market for wireless networking solutions will experience material increase in purchase orders, shipments and revenues.” Factors contributing to the increase included “the development of standards, improved technology and security (such as ISA 100 and wireless HART, mesh networking and WPA2, respectively).”
So far most wireless applications in the field have been in monitoring, data gathering and open-loop process applications, and the VDC study suggests this will continue. Areas of fastest expected growth were human machine interfaces, process controls and logic controls, in that order, but the fastest growth in percentage terms, said Shea, was expected to be in motion control, although much of that large percentage can be attributed to its present small base.
While industrial use of wireless is mostly for monitoring, Shea expects to it used increasingly in less-critical control applications, where latency of 100 ms or more is not a problem — things like pumps that need checking at intervals of less than one second, for example — but does not expect to see major adoption in the next three to five years.
Industrial wireless is different
We have seen an explosion in wireless applications for personal and commercial applications, like linking together computers, PDAs, printers and Internet access points, Shea went on, and in all of these applications the emphasis is on speed. He cited the IEEE 802.11 networks as an example, where the data rates have increased over time to 54 Mbps; in fact IEEE 802.11n, approved in 2009, can reach data rates of 150 Mbps. Few industrial applications need that kind of speed; data rates may be low indeed, down to a few bits per second or even per minute. In control and sensing applications, he explained, the greatest need is for reliability, accuracy and scalability: “Depending on the application, garbled or dropped data can result in anything from a disruptive glitch to a devastating failure.”
Choice of protocol
Multiple wireless networking protocols are available. The VDC study concluded that those based on IEEE 802.11b, 802.11g, ISA100.11a and WirelessHART would realize the greatest growth, with the latter two finding good growth and future demand in the process industries. Some legacy narrowband 2.4 GHz systems and even a few 800-900 MHz systems will find use where there is a need for greater distances, said Shea, as well as “a perception for greater reliability and greater security.”
When queried about perceived advantages and disadvantages of wireless, 52% of respondents to the VDC study felt that wireless provides solutions where wireline is impossible or impracticable, while 40% mentioned that it is easier/quicker to install. Also, 18% mentioned that wireless allows mobile applications, 18% that it is more suitable for remote locations and 16% that it is more flexible (easier to modify, etc.).
On the side of wired networks, 48% cited wireline as being more reliable than wireless (due to its noise immunity, etc.), while 35% of respondents felt that wireline is more secure than wireless. The same percentage said that they were more familiar with wireline, and found it easier to understand. Twenty-nine percent said that wireline has more bandwidth than wireless and is faster, 12% that it is easier to configure/specify, and 12% that wireless performs poorly in bad weather. Finally, 12% felt that wireless is not suitable for control applications.
When asked about their motivations for using wireless, 36% of respondents to the VDC study cited its flexibility and ease of expansion or relocation, while 29% were motivated by its easy/fast installation. Fifteen percent cited lower costs, while 13% were motivated by the desire to gain knowledge and experience with the technology.
Wireless networking is gaining steadily in popularity in the process industries, driven to a large extent by its ease of use, low installation cost and flexibility. Those supplying that industry would do well to remain abreast of that trend, and to take the necessary steps to make sure their products fit into the new paradigm.