Maybe it's because it's mostly invisible, but wireless networking in process control isn't getting the attention and respect it deserves.
Wireless may be intangible, but it's not insubstantial because it's holding up the capabilities and operations of a large part of today's industrial networks, extending the reach of Ethernet, and enabling cloud-based computing services, the Industrial Internet of Things (IIoT) and other forms of digitalization. Pretty heavy lifting for a technology that seems to have no substance.
However, just like "computing," "software," "networking" and other all-pervasive technical shifts that are so huge that they impact everything, wireless may also be reaching a level of success where it's everywhere. Ironically, like the other big topics, this is the point where it also become seamless, gradually taken for granted, and fades into the technological background. Before it does, however, it might be good to get a little refresher on what wireless can do and how to apply it properly.
"The base of the IIoT pyramid is all wireless," says Bob Karshnia, vice president and general manager of the wireless division at Emerson Automation Solutions. "The IIoT couldn't happen without wireless, but wireless is also adapting in many ways, too. The key to it all is data, and transforming it into actionable information that can improve operations and impact key performance indicators (KPIs). The next level for wireless is going beyond monitoring to improve reliability, safety and plant performance, perhaps by using our Plantweb Insight software, which has app-like tools and is like a Fitbit for process controls."
Bring in the field
While the word "wireless" logically suggests an absence of copper or at least less cabling, the potential savings weren't enough to get wireless to critical mass. What did push wireless over the top and enable it to "go viral" was that it allowed users to reach places and gather signals they could never get before.
For instance, Linn Energy operates about 1,500 oil and gas wells in the San JoaquinValley near Bakersfield, Calif., but it also runs a steam flood field, where steam is injected to provide pressure to force oil and gas out of the wells. Unlike fracking, this process doesn't use high-pressure liquid to fracture rock formations. The resulting water in Linn's process is treated to meet U.S. Environmental Protection Agency (EPA) standards, and injected back into an underground reservoir via more than 20 water-disposal wells. Water injection rates and totals are carefully monitored to meet EPA requirements and optimize disposal well performance. Surface or injection pressure is also monitored to meet EPA and safety requirements. Periodically, these wells need to be cleaned using a process called well-bore cleanout, but it’s difficult to determine precisely when to do these cleanouts.
Josh Hernandez, senior product engineer at Emerson, reports that Linn recently installed wireless pressure and totalizing transmitters on 15 water disposal wells, which helped it monitor productivity, eliminate unnecessary cleanouts, and save $150,000 in one year with similar savings expected in the future (Figure 1). "Significant savings were also realized because Linn Energy was able to determine that fewer new water disposal wells were required," states Hernandez.
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To reach this happy ending, Linn needed a better way to find out what was happening in its disposal wells, which are located about 500 feet apart. The company's task is to maximize well productivity by monitoring their performance, determining when they need to be cleaned out, and keeping them running to minimize the number of new wells that need to be drilled. "However, the wells vary in depth, length of perforations and other parameters, and well performance is indicated by the volume of water injected per foot of perforations," explained Hernandez. "Linn wants to maximize this value because it’s closely related to total injected volume of water, which indicates well productivity."
Previously, Linn personnel made daily manual rounds to read local chart recorders showing water flow into the wells, and read local gauges measuring surface pressure. However, because well operations and measurements change hourly, these rounds weren't sufficient to optimize cleaning or determine when to drill new water disposal wells. Clearly, Linn needed online monitoring and trending of key parameters, and due to the wells' remote location, battery-powered wireless transmitters were the most sensible choice.
"Many devices already integrate wireless like WiFi, cellular and 900-Mhz radios, and more people are willing to try it. So, the main driver today is ease of use, and making wireless even quicker and easier to order and install," says Justin Shade, wireless product marketing lead specialist at Phoenix Contact (www.phoenixcontact.com). "This is also helping remote access become more cost effective. For example, instead of traveling to do maintenance on a custom-built panel, we added our mGuard VPN appliance and our FL WLAN client device, and diagnosed the panel at the user's site over a secure VPN connection over the Internet. In fact, we just combined these two devices into a kit, so now our customers can get the security of our mGuard product line with the added flexibility of a reliable WLAN connection under a single part number."
Coordinate and build trust
Even though wireless can seem to be ubiquitous, there are still plenty of manufacturing applications where it could be beneficial if users weren't worried that it would be interrupted like a dropped cell phone call or their residential Wifi. Many system integrators and suppliers report it's been hard to dispel this prejudice, and convince potential users that industrial wireless is far more reliable than mainstream wireless—as long as its antennas, transmitters and receivers aren't installed under motors or metal roof soffits.
"There's a lot of people that don't trust wireless," says Scott McNeil, senior network and security engineer at Global Process Automation (GPA, www.global-business.net), a CSIA-member system integrator in Wilmington, N.C. "They may have some devices with WirelessHART protocol, but they won't add it on their own."
On the other hand, McNeal adds that pre-installation site surveys also remain essential because some new wireless converts seek to saturate their facilities with wireless, which can eat up air time and capacity, force applications to step on each other, and cause data collisions and drops. "To get users the data they want, role-based access is needed for access based on credentials, so they can only reach what they need. So, while plant managers get access to everything, operators and contractors only get to see the equipment they're working on."
McNeal also recommends using spectrum analysis to resolve wireless frequency conflicts. "We recently found some microwave dryers for industrial ceramics were running at 2.4 Ghz, which was interfering with the local WiFi," he explained. "This is why a site survey is needed to find local strengths and weaknesses. Once you have them, you can develop a wireless plan, which includes identifying the control measurements you want, arranging for role-based access, and designing to address signal coverage, antenna placement, access points (AP) or mesh, and power delivery. After deploying your hardware and logic—and training users—you need to maintain, monitor and stay secure with wireless intrusion detection devices, such as what is offered by Aruba Networks wireless controllers that can pinpoint if unauthorized traffic comes in."
McNeal added that one current problem is how to integrate cloud-controlled wireless into manufacturing because if its Internet connection goes down, then its wireless communications will be lost as well. "In this case, a non-cloud-controlled option would be best," he said. "Losing wireless in a corporate setting might be acceptable, but it could cause big financial losses and life safety issues on the plant floor. In general, wireles has been through the wringer and proved itself. The cloud and its security still needs to be proven."
Bert Williams, global marketing director for ABB Wireless, adds that, "It's important to remember that one 'I' in IIoT stands for 'Internet,' and one way to communicate over the Internet is wireless. Many of the same tools used for years on the IT and enterprise side can be applied to field networks including wireless. The question is how to scale up for IIoT applications? We can control wireless communication network management systems with our SuprOS solution, which offers fault, configuration, administration, performance, security (FCAPS) management."
Monitor and manage
Even if a process facility is way ahead on the learning curve, it can still benefit from wireless. For example, MOL Danube Refinery near Budapest is the only two-time winner of the FieldComm Group's (FCG) Plant of the Year Award for all its optimization efforts and performance gains over the past 15 years , but it recently started exploring and implementing wireless technologies to achieve even more gains (Figure 2).
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Overall, MOL Danube has a total of 40,000 instruments, including 30,000 with HART 4-20 mA, 8,000 with pneumatic and standard 4-20 mA, and 2,000 with Foundation fieldbus. As the only Hungarian MOL refinery conducting crude distillation since 2001, MOL Danube capacity is 8.1 million tonnes per annum (mtpa) with a 10.6 Nelson complexity index (NCI) ratio.
More recently, it pushed its use of FieldComm technologies up to 3,680 HART devices, 413 Foundation fieldbus devices, and 42 WirelessHART devices and six gateways, which receive signals from 32 devices usually measuring temperature and corrosion. Gábor Bereznai, head of maintenance engineering at MOL Danube, and his cohorts are also planning to adopt HART-Internet protocol (IP) with their OSIsoft PI historian and software. This adds up to about 4,700 intelligent instruments on the 15 critical unit connected to the SAP-PM computerized maintenance management system (CMMS).
MOL Danube's wireless projects include improving its WirelessHART and other wireless systems, and implementing an "uptime umbrella" reliability project to equip all key operating units with the plant's field instrumentation management system (FIMS), which includes revamping I/O interfaces, installing WirelessHART adapters, and replacing obsolete control valve positioners. Bereznai adds that MOL is also committed to using WirelessHART for corrosion control, instrument asset diagnostics, furance wall temperature measurement and heat exchanger performance monitoring.
"We found it was hard to justify the cost benefits of just one to three wireless PV transmitters, but the real benefits come from mid-sized projects," explains Bereznai. "Wireless also requires different design approaches. We also fond there were no significant performance differences between wired and wireless for fast-pipe diagnostics."
Similarly, ARC Resources Ltd. in Calgary, Alberta, Canada, recently sought to streamline operations and minimize cabinet space on a large, multi-well pad site in Dawson Creek, B.C. The pad had a ControlLogix PLC from Rockwell Automation and standalone flow computers metering natural gas, but each device could only handle an 8-meter run, and this wasn't sufficient for real-time data flows and future expansion.
Consequently, ARC decided to adopt Enhanced Flow Computers from ProSoft Technology that freed up enclosure space, reduced wiring, improved data integration, required fewer computers, and didn't have license fees.
“With this solution, we’re now able to do 16-meter runs per flow computer, limiting the number of units we need,” says Charlie Kettner, programming specialist at ARC Resources. “We also like that the system can be expanded later if we need more meter runs.”
Data from the desert
Back at its water-disposal wells near Bakersfield, Linn Energy implemented 15 Rosemount 3051S wireless pressure transmitters on existing manifolds to monitor the surface pressure, or the injection pressure, of each well.
To receive the signals, Linn installed one Emerson WirelessHART gateway, which was aided by three high-gain antennas due to the distances of some wells. The field gateway communicates to a base station gateway, which is also integrated with the facility's Rockwell Automation control system via EtherNet/IP. Next, 15 Rosemount 705 wireless totalizing transmitters were installed on the wells' existing turbine meters to measure injection rates and totalized values of injection water.
"Within minutes of installation, the 3051S transmitters began transmitting data to the control system, while the 705 wireless totalizers started talking to the control system in about five minutes," adds Hernandez. " "Emerson assisted with the next 14 wells, and the total installation and startup time was 10 minutes per well."
As a result, the wireless transmitters provide continuous data to better optimize Linn’s PC-based well performance model. The data is trended and used to calculate an "injectivity index" for the wells, which is a function of surface or injection pressure, injection rate and perforations per foot.
Linn improved its well-bore cleanout process by trending the surface or injection pressure at each water-disposal well to detect stoppages, which was better than relying on single daily measurements. Because well-bore cleanout is expensive and time consuming, the company estimates it saves $10,000 each time it avoids an unnecessary cleanout. It adds that it saved at least one cleanout a year for each of the 15 wells, which adds up to $150,000 in total savings.
"This success has led to four more water disposal wells being monitored since the initial installation, and more are planned," adds Hernandez.