Putting wireless to work in process operations

Emerson Automation Solutions
Saturday, 19 January, 2008



Wireless technologies offer process operations new opportunities for improvement. With a wireless strategy and architecture that align with your business needs, you can begin gaining the benefits today while facilitating additional applications in the future.

In past technology shifts, it wasn’t the technology itself (such as microprocessors or digital communications) that drove the shift; it was applications that took advantage of the technology to deliver value. Similarly, the adoption of wireless technology will be driven by the ability to more easily and cost-effectively extend and manage the flow of information around the plant.

Wireless technology is not a complete replacement for wires — at least not for a while. But it is already enabling new tools that give you the freedom to solve problems you could not cost-effectively address in the purely wired world.

There are many applications that are possible today without wireless technologies, but wiring costs or technical limitations make them impractical. Wireless technology can overcome these barriers, enabling you to gain better insight into your plant — and ultimately make your workforce more productive.

Wireless applications

Maximising the benefits of wireless technology will come from putting it to work in multiple applications. These opportunities typically fall into three categories: plant and process information; workforce productivity; business and plant management and security.

Applications for plant and process information

The more you know about the process, physical assets and overall operations of your plant, the safer and more profitable your business can become. More (and better) measurements mean more opportunities for reducing operational costs and improving quality, throughput and availability.

In addition, new environmental and safety requirements have been established after many of today’s facilities were built, and plants have struggled to get access to measurement and diagnostic information that could ease compliance. However, the cost or difficulty of adding new measurements has too often outweighed the perceived benefits.

Wireless technology removes the barriers of traditional wired solutions and gives you access to data that was previously out of economic or technical reach. This access to additional data includes not only process measurements, but instrument and equipment information as well.

For example, millions of smart HART-based devices in the field today have some level of diagnostics capability. Unfortunately, many plants don’t have the infrastructure to receive HART data into the appropriate system. Since only a fraction of these devices are digitally monitored, the potential gain from accessing such ‘stranded’ diagnostics is significant.

With wireless technology, existing wired HART devices can be upgraded with a wireless adapter to transmit diagnostics information back to the control room or maintenance shop. Process control signals continue to be communicated over the wired connection.

Capabilities like these open the door to a broad range of applications — from monitoring pressure relief valves and stacks continuously to avoid environmental excursions and the ensuing fines, to monitoring corrosion in pipelines and vessels or vibration in mechanical equipment. And with safety always a top concern in plants, knowing the real-time status of more plant equipment is critical.

Applications for workforce productivity

Even during normal operations, it’s not uncommon for a large plant to have hundreds of people working throughout the plant, often far from their control rooms, maintenance shops or offices. The new wave of wireless tools will dramatically improve the productivity of these people by providing instant access to information that they otherwise would have had to cover considerable distance to get to, or take valuable time from other plant personnel to find out.

For example, there are times when operators have to go out into the field. By providing remote access to control and asset-management systems, a ruggedised wireless PC can greatly enhance the efficiency of these people as they will be able to immediately relate what they see to what is happening to the process and take quick corrective action.

When operators are in the field, there may be no one in the control room watching for alarms. But with wireless access points throughout the plant, operators can use these PCs or similar tools to access critical process information, historical data, graphics and other key functions that normally reside in the control room or elsewhere in the plant. This includes viewing and acknowledging alarms from wherever operators are.

New wireless technologies can also improve worker communications. While many plant workers already use an older wireless technology for short-range communications in the field, combining a plant-wide wireless broadband network with voice over internet protocol (VoIP) technology can extend communication reach as well as enabling ‘smart’ communications.

Maintenance workers can benefit from these applications. Wireless tools such as handheld communicators allow these workers to access maintenance work orders, instructions and other information on the spot, and to immediately track or report inspections, tests and repairs.

To be deployed in the process industry however, applications like these must address issues such as harsh, industrial environments, high RF interference, bandwidth allocation and sharing the airspace with higher-priority control information from wireless field networks.

Applications for business and plant management

Wireless allows affordable access to information for better insight into what’s happening, especially for safety and security. For example, it’s easy and cost effective to add wireless cameras where it would be too difficult, costly or risky to trench or wire.

Many plants are already using wireless technologies to improve security. Wireless closed-circuit television cameras and RFID-equipped access badges enable intelligent security monitoring and control — from restricting access to specific areas based on levels of security, to tracking attempts to violate security protocols and helping security managers identify potential vulnerabilities and improve systems. Wireless applications can also enable you to monitor hazardous applications in order to reduce risk to plant personnel.

    

   

Wireless location technologies allow you to quickly find and track inventory and valuable assets — even workers — moving inside and outside the plant. Time spent looking for assets can be dramatically reduced, which can have significant benefits during major turnarounds, emergencies and new construction projects. Being able to quickly locate each worker also offers safety and productivity benefits.

An architecture that works for you

Gaining the benefits of the applications outlined above requires a solid foundation of wireless networks and infrastructure. To meet this need, an approach based wholly on open standards is needed so you can choose standards-based solutions without being tied to a specific technology or vendor.
For plant and process information applications: At the field network level, work is being done to effectively solve customer problems in process applications. For example, Emerson’s field products are based on WirelessHART and are committed to be compliant with this standard. There are also steps being taken to include WirelessHART technology in the SP-100 standard.
For workforce productivity and plant and business management applications: At the wireless plant network level, commercial standards such as IEEE 802.11 Wi-Fi, the emerging 802.11s Wi-Fi mesh standard and 802.16 WiMAX can be used to leverage the advantages of these readily available, widely supported technologies.

Wireless technologies for field networks

There are various wireless technologies available, but not all are suitable for the harsh environments found at most customer sites including the inevitable ‘canyons of metal’ that are found everywhere and that can present the inevitable problems for wireless signals. As a result, smart wireless solutions in the field must use a self-organising mesh technology which is the basis for the recently approved WirelessHART standard. Each wireless device in a self-organising network can act as a router for other nearby devices, passing messages along until they reach their destination.

This capability provides redundant communication paths and better reliability than solutions that require direct, line-of-sight communication between each device and its gateway.

Self-organising network technology also reduces the effort and infrastructure to set up a successful wireless network. One of the difficulties of setting up the traditional point-to-point wireless network is the requirement to do a site survey to be certain that every node in the system has a line-of-sight path. This survey work is expensive and also tends to require up to three times as many infrastructure nodes as a self-organising network.

Another advantage of self-organising networks is that they are dynamic. As new obstacles are encountered in a plant — such as scaffolding, new equipment or moving vehicles — the networks can reorganise around them. All of this happens automatically, without any intervention by the user.
Self-organising plant networks use IEEE 802.15.4 radios with channel hopping as the physical layer. They are designed and tested to be tolerant to almost all interference and can coexist with other wireless networks in your plant. The networks are also highly scalable and capable of one-second scanning with low latency.

Field testing of this technology by Emerson has demonstrated greater than 99.9% data reliability.

Wireless technologies for plant networks

Process plants present well-known challenges to the reliability and maintenance of electronic equipment, as well as requiring that those devices do not present dangers in hazardous environments. For this reason, devices used in plants, such as the Cisco Aeronet Outdoor Wireless Mesh Access Point, need to be built with rugged housings and be Class I, Div 2 certified.

Energy efficiency is also important for wireless devices and network components — users need long battery life and maximum maintenance intervals. Wireless instrumentation and control devices that include advanced power management techniques such as fast device wake-up times and low-power electronics, can offer a battery life of between 5-15 years depending on the application — and this is expected to rise at a rapid rate as battery technology advances.

Security

Plant owners have understandable concerns about protecting process performance and data, and so security has to be designed into a plant wireless system right from the start.

At the wireless field network level, robust security should be provided through advanced, standards-based encryption as well as authentication, verification, key management and anti-jamming techniques.

For example, Emerson’s Smart Wireless solutions employ end-to-end 128 bit encryption using the Advanced Encryption Standard (NIST standard FIPS-197). For authentication purposes, each gateway maintains a ‘white list’ of devices allowed to communicate with it, and individual devices accept messages only from a previously identified gateway or from other gateway-validated devices.

Separate ‘Join’ and ‘Network’ keys can be set to automatically rotate or be changed on demand. Implementation of the WirelessHART standard will add ‘Session’ keys for communication between two network devices so that other devices can’t ‘listen in’. These can be rotated as well.

    

   

Message integrity codes are used to verify messages, both per hop and end to end. Anti-jamming techniques such as DSSS with channel hopping plus multi-path routing help sidestep noise sources, whether malicious or not. And gateway-to-host security leverages well-known standards such as SSL as well as complete encryption and authentication.

At the wireless plant network level, systems should be compliant with 802.11i and Wi-Fi Protected Access 2 (WPA2), and employ hardware-based Advanced Encryption Standard encryption for wireless communication.

Put wireless to work for you today

Although wireless technology isn’t new, concerns about reliability, security and battery life have kept it from being widely adopted for applications in process environments. Those barriers have now been overcome by advances in device and network technology.

That means there’s no longer a reason to delay using wireless in your own operation. In fact, there are probably a host of reasons to start immediately: just think of all the ways that easy, affordable access to additional information could help you improve business and plant management, workforce productivity or plant and process operations.

Then pick an application — even a small one — and get started. The insights you gain from that first application will help you make even more of the technology in the future.

Emerson Process Management
www.EmersonProcess.com/SmartWireless
 

Related Articles

Industrial wireless networks — comparing the standards: Part 2

In Part 1 of this article, we reviewed the history of wireless sensor networks (WSNs) and defined...

Industrial wireless networks - comparing the standards: Part 1

Today wireless instrumentation is becoming more commonplace in process plants and is a more...

Modernise and maintain: implementing wireless to monitor beyond the P&ID

Many operational and maintenance problems around a plant can be solved by deploying WirelessHART...


  • All content Copyright © 2020 Westwick-Farrow Pty Ltd