1 June 2006
Plugging into wireless
By Gregory Hale
ISA survey shows users need to learn technology's capabilities
When it comes to the growing wireless sector, two big aspects are working together to hamstring widespread adoption: End user knowledge and perceptions of what the technology can do.
Whether these issues are real or perceived, the industry has to work toward educating users and to eliminate technological barriers, according to a survey conducted by Mann Consulting Inc. and commissioned by ISA.
Respondents did not see themselves as knowledgeable about current wireless technology, according to the survey. On a seven-point scale, with 1 being not very knowledgeable to 7 being very knowledgeable, the average score was 3.3.
"Right now (wireless) use is very minimal," said Gregory Johnson, director of product development at Compressor Controls Corp. "Everyone is very aware of it, but there haven't been any really killer apps out there yet."
"As in any new technology, I believe users will be educated as they apply the technology to new applications," said James Sprague, instrument and control specialist with a Middle East oil company.
Knowledge often leads to whether an end user will trust the technology. While the average survey score for trustworthiness was a bit higher, it still came in at 4.2 on the seven-point scale. The number did increase, though, among those that thought they had average to above average knowledge of wireless technology.
Knowledge is trust
It goes to show; the more knowledgeable a user is about the technology, the more willing they are to trust it. In the total survey, 13% of respondents ranked the technology as being trustworthy at 6 out of 7, but among those saying they had an average or above knowledge about the technology, just over 23% ranked it a 6 out 7.
"For the time being, wireless is trustworthy enough for the non-critical applications that we use it for," Sprague said.
"There are numbers of applications where wireless is cost effective and useful today," said Wayne Manges, program manager of industrial wireless programs at Oak Ridge National Laboratories, managed by UT-Battelle and chairman of the ISA-SP100, Wireless Systems for Automation committee.
He pointed out the Comanche Peak nuclear plant in Glen Rose, Tex., has a $14 million wireless operation running today. "It paid for itself in two years," he said.
"Right now the industries using wireless most are the ones that can not afford downtime, like refining, power generation, and even sewage treatment plants," Manges said.
"Power generation (downtime) right now translates into dollars from the bottom line." Sewage treatment plants can't afford downtime because they are approaching capacity from increased development and population growth, he said.
Concern over security of wireless is the top worry among survey respondents at 26.9%, followed by lack of confidence in the technology, 11.7%; lack of reliability, 11.2%; experience with system, 9.4%; performance not adequate, 6.3%; no industry standard, 4%; and rapidly evolving technology, 4%.
"Currently, there is commercial off-the-shelf technology that can make wireless as secure as wired," Manges said. On top of that, he said, "there is technology on the horizon that can make wireless more secure than wired."
Right now, according to the survey, users believe acceptable wireless solutions exist for 20% of total potentially wireless applications. And for down the road, the expectation is about 40% of total solutions can someday become wireless if the technology is secure, cost effective, and reliable, according to the survey.
"We are not seeing it used in plants, but in the next couple of years, we will see greater use," Johnson said. "As soon as some major people like GM or Ford accept it, it will gain greater acceptance."
Another hot issue revolving around the wireless arena is standards. Users said adopting a standard or standards has the potential to help reduce or remove barriers to adopting wireless technology. About 33% of respondents mentioned the lack of standards was a barrier to deploying wireless solutions.
Users said standards will be critical to meeting two important needs: A common management tool in intermingled wireless application environments and allowing the development of interoperable devices from a variety of vendors for a range of industrial wireless applications, according to the survey.
"From my view, the key area for understanding is not the technology but the standardization," Sprague said. "I, as a user, want vendor consortiums to produce SP100-based standard wireless protocols—so I can mix and match instruments with a standard, robust, and secure wireless network—and can easily bring these process measurements into my existing DCS."
For Manges, the challenge for adopting wireless in the industrial environment comes down to four issues: How to balance security, reliability, throughput, and latency. "Those are the Fab 4 and solving them is the key."
Latency is especially important in a real-time environment, he said, because there has to be an immediate response from when you request a command and how long before it actually happens and then getting a response back saying it occurred.
The first wireless "killer app" was about in 2002, and that dealt with radio frequency (RF) tags, Manges said. That allowed for supply chain visibility. Then the next killer app, occurring right now, is what Manges calls asset monitoring where your can monitor equipment and its performance.
Next will be process visibility where a user can monitor what happens to raw materials as they go through a process, Manges said. The user can view what happens as the materials convert from raw to a product.
He said that is where standards comes in. The goal of ISA's SP100 committee is to integrate these applications to the enterprise.
Live and learn
While the industry is in the early stages of adopting wireless technologies, there are some who learned lessons when they installed and used wireless devices.
The main thoughts behind those early adopters focused on design and setup that takes into consideration the site (sight line for the signal [current, future], grounding, lightning suppression, dead spots, and redundancy); understanding the limitations of the devices beforehand; adequate planning and testing (strength of signal, interference, and reliability); and security issues.
Just over 6% (6.7%) reported installing wireless was easier than they thought it and wish they had done it sooner.
Wireless right now is not perfect, but Manges said that is no reason to wait.
"It is like asking if my PC is reliable. If anyone waits for it to be totally reliable, you will be left in the dust. Should you wait? No way. The only way you lose is if you sit and wait."
As it is with any different technology, there are always barriers to adoption. Wireless is no different.
One of the drawbacks for wireless, Johnson said, is the industry is not quick to accept or adapt new technology. "If someone came up with a wireless app that can only be done via wireless, then it will get accepted."
"Right now wireless is used to replace a wired solution, but the problem is people know wired technology, so why should they change," Johnson said.
Sometimes when there is a wireless application, a user has to overcome initial obstacles. Manges said he was on one site survey, and a user in the plant couldn't figure out why the wireless connections were not working around noon. They did a site survey and found people were using microwave ovens to warm up their lunches, and that was having an affect on the wireless connections. They were able to work around that problem.
Respondents selected the top barrier from the list of those reasons they had previously selected, and the top choice turned out to be security. Expected performance, reliability concerns, and inadequate performance of current systems are the next most commonly cited barrier to adopting wireless. In addition, nearly one-third of respondents mentioned "no industrial standard" as a barrier.
While the talk around the industry today is all about making technology interoperable, the survey shows it is not a barrier right now. However, as the technology becomes more prevalent, interoperability could move up in importance.
In terms of which application meets end user needs, the old saying that goes "you don't know what you don't know" comes to mind. Almost half the respondents (46.6%) did not know the answer to this question. Even among those respondents rating their knowledge average to above average, 30.1% said they didn't know. About one-fifth of the respondents did say 802.11 WiFi (a/b/g) is the best solution. One-tenth said proprietary solutions filled the bill.
"Currently, from my process instrument perspective, the only real advantage is the 'no-wires' part," Sprague said. "The applications are in non-critical 'monitoring only' instrument upgrades or modifications on an existing plant where rewiring is very expensive. New sensors may also require battery operation." But, Sprague added, "you can envision the time when other advantages are offered, such as wireless field communicators, DCS HMI stations, and upgrading older plants to get 'smart' instrument diagnostics via a wireless route, while the 4-20mA process signal travels conventionally."
What does the future hold? "For me," said Herman Storey of Shell Global Solutions (U.S.) Inc., Automation Engineering, "the most important question is not what is the current state of wireless, but what is the ultimate potential of wireless, and what do I, and my industry, need to do to take advantage of that potential."
Congestion of wireless signals
Editor's note: There are all types of wireless technologies; different frequencies, different data rates, different power requirements, different prices. In a quasi-scientific test at ISA EXPO 2005, the authors measured what happens in a confined area with wireless devices operating at the same time.
By Peter Fuhr, Hesh Kagan, Rob Conant, and Jose A. Gutierrez
With over 90% of all equipment/instrument vendors displaying components and systems with wireless capabilities at ISA EXPO 2005, wireless was on display all over the show floor.
In the exhibit hall's Industrial Wireless Pavilion, wireless devices were up and running. A quick unscientific query of the exhibitors revealed the vast majority of the products were set to operate in the (unlicensed) Industrial, Scientific and Medical (ISM) frequency bands. While there are many ISM frequency bands available for use in the U.S., due to bandwidth and operational restrictions, most of the wireless traffic was concentrated in the 902-928 MHz and 2450 (+/-) frequency bands.
In standards-compliant wireless operation, most devices have gravitated to using either an IEEE 802.15.4-compliant wireless channel or an IEEE 802.11b/g compliant channel. Please note, not all of the exhibited devices operated under IEEE-compliance, rather they could run their own protocol and broadcast in the ISM bands. The result is easy to predict, namely numerous sensors/instruments/transmitters all attempting to operate in the same 900 and 2400 MHz channels, resulting in considerable congestion and coexistence issues.
There is no requirement for devices operating in either of these bands to comply with either of these standards—plenty of wireless devices are simply sensors/devices onto which has been slapped a "conventional" wireless transmitter. As long as their radiated power doesn't exceed the maximum value, the device is "compliant" with operating in an ISM band.
After obtaining a background noise floor spectral snapshot, we walked onto the exhibit floor at 7 a.m. on the second day of the event, turned on the portable spectrum analyzer, and tuned it into the 900-930 MHz range. With very few people, it set the stage for a "quiet" moment to take measurements. The amplitude level was flat at -82dBm.
A different electromagnetic "scene" occurred at 12:30 p.m. the same day. The EXPO floor was buzzing with vendor displays operating and hundreds of people walking around. We picked up the spectrum analyzer and returned to the same physical location on the exhibit floor where we first took the noise floor measurement. With the analyzer set to the same sampling/measurement settings, we measured significant congestion. Peak amplitudes top out around +5dBm, with local minima in the -25dBm range—a 67dB increase (in regular numbers a factor of over 6,000,000).
Later in the day, we grabbed the analyzer and repeated the 900 MHz measurements, but this time performing a time average to ascertain the average channel activity.
It is difficult to present definitive information on the impact of such RF congestion on system performance. We obtained anecdotal "evidence" by walking around and talking to exhibitors and asking how their demos were functioning. The "study" results verified what the measurements showed: significant channel congestion and systems that didn't always function as hoped for.
We reiterate this was a quasi- (at best) scientific study conducted in a somewhat unnatural setting of an exhibit hall with literally hundreds of vendors' wireless systems operational. On the flip side, if the analysts' forecasts are right with thousands of wireless sensors and networks deployed throughout industrial settings, it is probably worthwhile to give a bit of attention to congestion in ISM band traffic and the associated negative effects of co-channel interference.
Two IEEE standards groups are working toward addressing the coexistence issue, namely P802.15.2 – Recommended Practice for Coexistence in Unlicensed Bands and 802.19 – Coexistence of Wireless Data Transport.
Two organizations are attempting to bridge the chasms between IT, wireless, and industrial bus systems with a focus on a standard for coexistence and interoperability of networked systems in industrial settings: WINA (www.wina.org) and ISA's SP100, Wireless Systems for Automation committee (www.isa.org/community/sp100).
About the authors
Peter Fuhr is with Apprion, Hesh Kagan is with Invensys, Rob Conant is with Dust Networks, and Jose A. Gutierrez is with Eaton. In addition to their duties at their respective companies, all four are on the executive teams of the Wireless Industrial Networking Alliance (WINA) and ISA-SP100.
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