In August 2011, IDTechEx published a survey, "Wireless Sensor Networks 2011-2021." In it, the researchers claimed that wireless sensor networks will grow from $0.45 billion in 2011 to $2 billion by 2021. Most of that growth will be in smart homes, smart grid and other non-industrial applications.
Raghu Das, CEO of IDTechEx says, "In 2011, industrial wireless sensor networks account for approximately 6% of the total $0.45 billion. In 2021, they will account for approximately 28% of the estimated $2 billion market."
"In 2011 I'd estimate WirelessHART to be 60% of that market segment that is industrial only," Das continued. It is difficult to predict its use in the future—the choice of standards is a problem."
A recent survey by Control magazine indicates that the prediction may well be easier than Das thinks. According to the survey, published in the August issue, end users have stopped waiting for the standards to be hashed out and have begun selecting WirelessHART over other standards. Part of this is undoubtedly true because WirelessHART is now the only international open standard for wireless sensor networks: IEC62591-WirelessHART.
As a further insight, the Control study showed that 18% of respondents said they didn't need wireless networks—any variable they needed badly enough was worth running cable to. If you remember that HART Communication is both wired and wireless, this is an important advantage to end users and asset owners. You can continue to use your wired HART systems and when there is a need, a WirelessHART network will fit right in.
Interoperability Makes WirelessHART Work
A unique feature of WirelessHART is its integration with the wired HART specification. Just as all HART instruments—including WirelessHART— have been interoperable and backward-compatible. You already know how to commission and calibrate the wireless versions, because you already have HART smart devices in your plant. There is no run-up learning curve.
"From the E+H perspective we support all standardized communication protocols which of course includes WirelessHART"says Endress+Hauser (www.endress.com) wireless product manager Jason Knuteson. "Our customers are continuing to ask for robust and flexibility solutions for difficult process applications they experience, and WirelessHART is a great answer to their needs!"
What does interoperability really mean? It means that any HART device of any kind will work seamlessly with all other certified and registered HART devices. Further, for its basic functions at least, any certified and registered HART device can be interchanged with any other similar device. So every HART temperature transmitter is interchangeable, and so forth. For WirelessHART, it means that any WirelessHART gateway can be used with any manufacturer's devices, and all devices can be used with any gateway.
The WirelessHART Ecosystem
Proprietary wireless systems and even some so-called standard systems generally have only one vendor. This can be very worrisome for the operator when selecting a wireless network for the plant. Since 2007 when it was introduced, the number of vendors producing registered and certified WirelessHART devices (the HART "Ecosystem") has been climbing—now numbering around 20. These vendors include the manufacturers of at least 80% of all transmitters, control valves, and online analysis equipment, such as Siemens, Endress+Hauser, Moore Industries International, Emerson Rosemount and Emerson Fisher.
"Siemens is continuing to see a strong demand for our WirelessHART products and solutions," says Michael Cushing, product marketing manager for Siemens Industry, Inc. (www.sea.siemens.com) "and our SITRANS products are the cornerstone to our portfolio. Cost and efficiency is driving this demand, as WirelessHART users eliminate significant costs of cabling and installation, and realize the convenience of faster commissioning and easier maintenance. We also have the ability to interface WirelessHART with other Siemens process instruments through our SITRANS AW200 adapter. Customers will continue to have the need for easy access to information from plant applications and operations, and WirelessHART is well-suited to provide diagnostic information on measured process values."
What this means for you is that you have much less risk selecting WirelessHART for your wireless sensor network than in selecting any other system. It means that WirelessHART is "future proof." You can be certain that the HART Communication Foundation will maintain the full backward compatibility that has become its hallmark.
So Who's Waiting?
You may not be waiting at all. According to the wireless study published in Control's August 2011 issue, 43% of respondents said they already had wireless field networks, while another 27% said they were planning to install them in the next 1-3 years. If that's the case, the next step is to learn how to design, configure, manage and operate IEC62591-WirelessHART sensor networks.
Setting Up WirelessHART
"The WirelessHART standard is built on proven industry standards," Executive Director Ron Helson says. "The radio uses the IEEE 802.15.4 standard and requires extremely low power, enabling the battery to last as long as 10 years in some applications. The radio operates in the same license-free 2.4 GHz band as Wi-Fi and many other wireless technologies. WirelessHART uses channel-hopping and channel black-listing to prevent interference and enable coexistence with other wireless networks, and a combination of star and mesh topology networking to ensure robustness in the presence of noise."
Helson continues, "WirelessHART uses the Electronic Device Description Language (EDDL) (IEC 61804-3) to simplify system integration as well as enabling setup, calibration and device diagnostics using graphical interface software applications."
WirelessHART was designed to operate reliably in a process plant environment that is full of structural steel, metal vessels and pipes using industry-accepted mesh topology. WirelessHART mesh networks are easily deployed without the need for installing a wireless infrastructure of backbone routers in many plant areas and providing power for them.
What you need to get started is a scale drawing or photo of your plant. Several companies make wireless sensor network management equipment that allows you to overlay the physical location of the sensors on the scale drawing, and tell you whether you need repeaters, more sensors or more gateways. For an example of this, see the Emerson AMS snap-in component in Figure 4 of "HART -- the Premier Tool for Asset Management."
Real World, Real Answers from WirelessHART
BASF had a real problem. Technicians needed to measure the temperature in a rotating vacuum dryer full of catalyst. Because the dryer rotated, wired temperature sensors had been eliminated. They were stuck with manual sampling and lab testing. They needed something better and faster.
"We went in search of alternatives so that we could dispense with the time-consuming sampling process and free up the operators," say Ramon Kranendonk and Perry Stofberg pf BASF in DeMeern, the Netherlands. "On the Endress+Hauser stand at a trade fair, we saw a demonstration of a wireless system for measuring temperature. The system used standard transmitters and a module with an antenna was used to transmit the data signal to a host by means of WirelessHART. For us, this was obviously an excellent solution."
Kranendonk noted that another criterion was the straightforward integration into the system. Control is via Siemens PLCs and PROFIBUS. Their asset management software is FieldCare. The Fieldgate gateway has 24 VDC power, and two outputs: one Ethernet, and one Modbus. The Modbus signal is converted to PROFIBUS DP and fed to the PLC. The Ethernet signal is sent to the FieldCare server.
"BASF has a number of good applications for wireless communication, and we are putting them to good use," Kranendonk says.
This application shows another unique feature of IEC62591-WirelessHART. A wireless adapter can be retrofitted to an existing HART wired transmitter to turn it into a fully functional wireless transmitter. Like the rest of the HART ecosystem WirelessHART adapters are being made by several vendors, including Endress+Hauser, Emerson (www.emersonprocess.com) and Pepperl+Fuchs (www.pepperl-fuchs.com). MACTek (www.mactekcorp.com ) produces a "Bullet" WirelessHART adapter that permits up to eight wired HART transmitters to operate wirelessly. Some of these wireless adapters provide their own power supply or can be used to power the transmitter, and some get their power from the current loop connected to the wired HART transmitter.
"WirelessHART easily scales to support large applications with separate networks for each plant area aligning with DCS structures and division-of-work responsibilities that make it easy to manage and more secure," Helson says.
Northstar Bluescope Steel had a real problem. The steel mill has water-cooled electric arc furnaces, with water-cooled burners and cooling panels that keep the furnace walls from melting and deforming—and blowing out the panels. If that happens, the furnace is seriously damaged, and just one blown-out panel costs upwards of $20,000 to repair. Then there is the lost production cost due to the unexpected downtime. That can be as much as an additional $200,000 per day or more.
"Between nine and 12 measurements per week would fail due to high temperatures or physical damage to sensors, cable or conduit," says Rob Kearney, maintenance supervisor of Northstar's mini-mill in Delta, Ohio. "And when a measurement point fails, the furnace must be shut down. The new wireless solution eliminated almost 100% of the cable and conduit—which reduced maintenance costs by $200,000 annually."
The self-organizing WirelessHART network collects the data used to control temperature on the furnaces. Emerson provided 32 Rosemount WirelessHART temperature transmitters, 28 for control and four for monitoring. The transmitters send their data to aWirelessHART gateway which interfaces with the mill's transformer-regulation and burner-control system.
"Safety has also been improved," Kearney says. "The furnace's cooling panels are operating consistently at a safe temperature, and there is less maintenance required around the hot furnace shell, where ambient temperatures can be +140 ºF."
Is HART Future-Proof?
The process industries, in fact, all manufacturing, are very conservative. Refineries and chemical process plants especially don't like trying new things, because a failure generally makes something go boom. Pharma and biopharma plants and other validated industries are similar in conservative application of new technologies.
But HART and its wireless capability, WirelessHART, aren't new. They are both based on the proven technology that has made HART the standard for process fieldbus. And going forward, you don't have to fear that suddenly the devices will become obsolete. Endress+Hauser is one of the world's two largest field instrument manufacturers. Here's what Jason Knuteson, E+H wireless product manager, has to say, "The long-term investment and commitment into the WirelessHART and other wireless communication is 100% from E+H. This is a decision made at the top levels within our organization! We are committed to the needs of our customers."
David Skelton, Phoenix Contact's (www.phoenixcontact.com) vice president Americas sums it up well. "Process engineers around the world are using WirelessHART as a way to easily obtain data from their existing HART or newWirelessHART instruments. With this gateway, Phoenix Contact has combined our competencies in wireless, networking and process technologies to develop a product that makes WirelessHART networks even more cost-effective and flexible."