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The integration of ISA100 and wireless HART. and ISA100 organizations established a joint task for WirelessHART and ISA100.11a.

The integration of ISA100 and wireless HART. and ISA100 organizations established a joint task for WirelessHART and ISA100.11a.

Paul Sereiko

We’ve witnessed an explosion in the availability of wireless networks for employees and consumers–home and corporate wireless LANs are ubiquitous, Wi-Fi hotspots are in airports, Starbucks, etc. However, if Guglielmo Marconi received the Nobel Prize for developing the first wireless telegraph more than 100 years ago, why has widespread public adoption only occurred recently?

While one can certainly point to a variety of factors, perhaps the single most important one has been the development of industry standards. Without the development of the 802.11 (Wi-Fi) protocols and the emergence of global mobile communication standards, the consumer marketplace would certainly not be enjoying the conveniences afforded by the “wirelessly connected” world.

Lack Of Standards Stalling Adoption

In the industrial marketplace, wireless adoption has been much slower. With the exception of long-haul proprietary wireless SCADA systems, the use of wireless in industry is extremely limited. In fact, in surveys conducted by ISA, we’ve found that although most large process facilities have several thousand wired monitoring and control points installed, the number of wireless points in those same facilities is counted in tens. Why is there such a big difference?

A lack of standards suitable for industrial wireless usage plays a large part in causing this gap. In a coffee shop, it may be irritating but acceptable if a browser stops responding while downloading the latest results from your fantasy football league. Wait a few minutes or walk to a different part of the store and the problem is usually solved.

Unfortunately in industry, even if the application is simply monitoring, this type of performance is simply unacceptable. Furthermore, in the coffee shop, if your laptop battery goes low, you can easily find a plug. And even if you’re using a nifty Apple MacBook, you can be sure that it will connect with the Cisco router deployed in the store. Layer on top the process industry’s requirements for operation of the wireless devices in hazardous–even explosive–environments, and you have an arena where what’s taken for granted in the consumer market is not standardized for industrial applications.

New Technology Enables Development Of Standards

Two important innovations in networking have recently led to a tipping point for standardization of industrial wireless. The first is a concept known as mesh networking. To understand mesh it’s good to start with a description of the most common network topology … the star or hub and spoke. In a hub-and-spoke network all traffic moves between the network end points and the hub. A Wi-Fi network is a good example of such a hub-and-spoke topology (Figure 1).

[FIGURE 1 OMITTED]

If something obstructs the radio path between the end point and the hub, connectivity–also known as the link–is lost. In other words, the performance of the network is dictated by the channel link between the hub and the end points. So while the topology may be somewhat new and improved, the performance follows metrics established decades ago. Mesh networks do away with this restriction by allowing data to move through multiple end points to the hub, sometimes called a gateway as this point often also serves in the role of protocol conversion (Figure 2).

[FIGURE 2 OMITTED]

The second innovation is the standardization of a new class of low-power consuming, low data rate radios by the IEEE. From many perspectives, IEEE standard 802.15.1 set the bar for low power-consuming radios and became more commonly known as Bluetooth. The system transfer rate was moderate (~750kbps) with a node separation distance in the 10s of meters range and having to recharge/replace batteries every few days is acceptable–except in the industrial arena. Under the IEEE 802.15.4 specification, this standard was first approved in 2004, then modified in 2006. Today, many silicon vendors make radio transceiver components in compliance with this standard.

By leveraging IEEE-compliant radio standards for the transport of industrial fieldbus data, the issues associated with deployment in and integration into industrial process facilities are more readily addressed. Two standards under development are aimed at industrial wireless sensing solutions using mesh networking and IEEE 802.15.4 radios.

The HART Communication Foundation (HCF) is working on WirelessHART, an open wireless mesh networking communications protocol aimed at leveraging the information collected by the nearly 25 million installed HART [Highway Addressable Remote Transducer] devices. WirelessHART is geared specifically to the process industry, with a goal of adding wireless capabilities to the HART protocol to enable reliable, robust, and secure wireless communication in real-world industrial plant applications.

Compatibility with existing HART devices and applications will be maintained, according to the HART Communication Foundation. The WirelessHART specification was released in 2007 and products are expected to be available in the marketplace by the second half of 2008.

The second standard is ISA100. It is being developed by the ISA organization as a family of standards. ISA100 will support multiple protocols, including its own native protocol and others such as HART, Profibus, CIP and Foundation Fieldbus, on a single integrated wireless network. The current release of the standard, ISA100.11a–the component of ISA100 that is involved with wireless transport of field transmitter measurements–is focused on process automation, but does not exclude factory automation applications.

The ISA100.11a single wireless network will accommodate all current and future application or system protocol needs while preserving existing protocol investments. To ensure compatibility, continuity, and uniformity, the two groups are cooperating and relying heavily on end user and vendor input. (Figure 3). The ISA100.11a standard is in the comment period and is slated for release before the end of 2008.

[FIGURE 3 OMITTED]

Creating uniformity and building standardization into industrial wireless communications is the necessary objective for peaceful co-existence. Without standardization, uncoordinated transmissions over the same frequency, at the same time and in the same area will lead to congestion and interference, creating a losing proposition for all.

To achieve this objective the HCF and ISA100 organizations established a joint task force in October 2007 to evaluate interoperability and co-existence options for WirelessHART and ISA100.11a. The task force has worked hard to ensure that WirelessHART and ISA 100.11 a networks can co-exist peacefully in the same facility. Initially, interoperability will be limited to the system gateway.

In other words, a WirelessHART mesh and ISA100.11 a mesh will operate independently, but a single gateway device could service both networks, enabling field data to be integrated with plant applications as if there was a single wireless system. Ultimately, the task force’s goal is to extend interoperability into the mesh network as well. This tighter integration would enable WirelessHART and ISA100 devices to work together on the same wireless mesh, further simplifying the ability of users to take advantage of standardization.

“Everyone seems to agree that incorporating WirelessHART in the developing ISA100 standards is in the best interest of the industry, preserving both current and future investments,” says Ron Helson, Executive Director of HCF.

New Products For The Wireless Industrial World

Just as standardization of Wi-Fi has led to many new types of networked products, standardization of industrial wireless is driving innovation for products that deliver a wide range of valuable new capabilities. For example, with WirelessHART, automation suppliers will be introducing Wireless Adapters that retrofit existing wired HART field devices. The adapters wirelessly transmit HART data and commands so that data that would otherwise be stranded on the device can be integrated with plant applications such as asset management, historians, advanced control, or energy management.

With data being stranded for an estimated 85% of all installed HART devices, or more than 20 million devices, the potential for improving plant operations with this type of innovation is substantial.

Interoperability

An important component of the deployed network is not just the aforementioned wireless field transmitters, but also the network components that are required to get the measurements from one location in the facility to another. Viewed another way, while the plant operators are keenly interested in using wireless technologies for process optimization or perhaps increased points under management by the DCS, there are other individuals and organizations within the plant that may be using wireless technologies for other purposes, such as video security monitoring, Voice over Wireless LAN, mobile operators (tablet PC, PDAs), health and safety monitoring (the list continues!).

There is a high probability that the wireless infrastructure to be used to support those applications may also be used to deliver the processcentric information

The co-existence of these RF signals or monitoring the network health to see when performance degrades (or rogue users try to access the network) are security and network management functions that are also described within ISA100.11a. The wireless technologies used for these various pieces of the puzzle differ, but a common network management system and intelligent network appliances are available.

Demonstrations of each of these elements were shown at the ISA100 demonstration that took place at ISA Expo 2007 (Houston, October 2007)–the net result being multiple vendors’ sensors and systems all operating simultaneously in one physical location.

Conclusion

The lack of standardized wireless protocols and lack of device interoperability is a contributing factor to the circumspect or experimental deployments that we have seen to date. The combined WirelessHART and ISA100 standards will end niche application implementation and usher in the widespread plant adoption rates that have been anticipated in the marketplace for years. Through the collaboration of these two standards, any potential for end-user confusion and hesitation surrounding implementation will be eliminated. There is no longer the need to wait and ultimately do nothing for fear of making the wrong decision.

Completion of the Wireless HART and ISA100 standards is critical in enabling a variety of industries to finally–and enthusiastically-embrace wireless technology to improve productivity. Solution vendors willing to commit to developing products that effectively employ these standards will likely reap dramatically increased sales. These vendors will be handsomely rewarded for their efforts to overcome key hurdles, including security, interoperability and reliability, and integration of standards with existing operations.

Wireless is an old technology that has a tremendous amount of innovative capability. And as wireless permeates all facets of our daily lives, we must not only thank Marconi and many others along the development path, but we should also recognize President Teddy Roosevelt for having the foresight to lay the groundwork for standardization through regulation and oversight of wireless communications during its earliest days of existence. P&GJ

SOURCES

Wireless Data Technologies, by Vern A. Dubendorf 2003 ISBN: 0-470-84949-5

“Wireless Proponents Take HART” by C. Kenna Amos for ChemicalProcessing.com

“The Right Standard at the Right Time” by the Hart Communication Foundation, October, 2007

By Paul Sereiko, President & CEO of AirSprite and Peter Fuhr, CTO of Apprion, (both members of the ISA SP100 Marketing Group)

Authors: Paul Sereiko is the President and CEO of AirSprite Technologies Inc., a wireless sensing software and infrastructure company based in Marlborough, MA. He is also Co-Chair of the ISA SPIO0 Marketing Working Group and member of the HART Communication Foundation.

Peter Fuhr is the CTO of Apprion, a wireless application network systems and services company based in Moffett Field, CA. He is a founder and executive board member of the Wireless Industrial Networking Alliance (WINA), a senior member of IEEE, and chairperson of the interoperability committee within the SP100 standards organization

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COPYRIGHT 2008 Gale, Cengage Learning