Automation unplugged

Wireless technologies present compelling opportunities for the utility sector to implement applications that they simply could not justify with traditional wired technology.

Wireless networks can provide real-time accurate data and visibility into equipment performance, field workforce, consumer consumption and the whereabouts and utilisation of other assets, from trucks on the road to spare parts on warehouse shelves.

Wireless process automation, meanwhile, enables information to be gathered from remote sensors at hard to reach or even dangerous unmanned sites, which would otherwise be measured infrequently. The opportunity now exists to take readings from rotating or moving plant equipment.

The obvious attraction of wireless is the major cost savings compared with wired installations. For example, installing additional wired measurements within hazardous areas of a plant is often cost prohibitive.

Wireless reduces the expense of installation by as much as 90%. Installation is simplified since it is not necessary to plan and run conduit and cables to every device. Users are also relieved of the complexities and limitations of physical wiring.

By adopting wireless communication techniques, operators, maintenance and IT personnel, and management gain convenient access to information that would previously have been unobtainable. On top of that, wireless technologies can help to improve productivity and safety, and, ultimately, reduce operational costs.

Mesh networks

There are various wireless technologies available for industrial applications, but not all are suitable for the harsh environments found at plants, including the inevitable “canyons of steel” that can present problems for wireless signals. However, self-organising wireless mesh networks overcome these obstacles to deliver reliable, secure communications.

Mesh networks combine smart monitoring devices with wireless transmitters, networked together using Time Synchronised Mesh Protocol (TSMP) communications technology. The 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 co-exist with other wireless networks in the plant.

The transmitters have a maximum range of 150-400m, depending on the location, and as many as 100 devices can relay information back to one gateway. Wireless upgrade modules can even be fitted onto existing wired devices.

As new wireless devices are added, they connect automatically to the self-organising network. New nodes beyond the range of a gateway pass their messages through other wireless devices until they reach the destination.

This wireless mesh technology is easily scalable, since repeated extensive site surveys are unnecessary and new devices can be online within 30 minutes of installation. With this plug-and-play functionality, plant or grid coverage can easily be expanded as requirements change.

Traditional point-to-point wireless networks require a site survey to ensure 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 than a self-organising network.

Another advantage of self-organising networks is that they are dynamic. If something disrupts communication between transmitters, such as scaffolding, new equipment, or moving vehicles, the self-correcting system recognises the problem and automatically re-routes the data traffic along the next best path.
 

This results in a communications reliability that is greater than 99%.

Wireless technologies also enable this data to be more readily available to those who need it. By using the information received from the wireless devices within the control network and then introducing technologies such as Voice over Internet Protocol (VOIP), video and handheld tablets it is now possible to make the data available over a plant-wide network.

This enables users to track people and assets, to send alarms, and to provide historical and live data to mobile operators.

Joined-up thinking

Emerson Process Management is one of the pioneers of wireless automation. In 2006, the US firm introduced Smart Wireless solutions using self-organising mesh technology with TSMP protocol, thereby extending and unplugging its PlantWeb digital plant architecture to connect intelligent field devices wirelessly.

The system addresses the issue of security by providing advanced, standards-based AES 128-bit encryption as well as identification, authentication and validation techniques, verification, key management, and Direct Sequence Spread Spectrum (DSSS) anti-jamming techniques.

Earlier this year, Emerson announced that it was collaborating with Cisco to offer open-standard solutions for wireless process and plant management applications that install easily and operate reliably in challenging industrial environments. The network uses tools normally found in the office environment such as email and internet.

This is achieved by integrating Cisco wireless access points throughout the plant giving plant-wide coverage.

For example, a maintenance operator who is already out in the plant is now able to receive valve diagnostic information directly to his handheld PC.

Emerson will use the Cisco Unified Wireless Architecture to provide wireless LAN coverage and integration within the plant’s existing IT infrastructure, eliminating the need for a complex wireless overlay network.

Cisco’s Wireless Control System will centralise the configuration and management of the plant’s Wi-Fi network, reducing overall cost of ownership.

“Cisco and Emerson are market leaders in complimentary areas: Emerson from a process automation, control and instrumentation point of view and Cisco from a networking point of view,” says Huw Pegler, director of manufacturing sales for Cisco.

“The reason we are able to integrate with Emerson is we believe in open standards. Everything Cisco does is driven by open; it enables us to integrate with our partners both from a customer perspective and also enables us to ensure future proofing.

Our solutions are scalable, and, as standards and as our customers’ needs develop, we are able to move with them in that direction.

Pegler continues: “In the 1980s we had the concept of three different networks: data; voice; and video or security network.

These would have been completely separate networks, which, from an IT point of view, adds complexity and makes these networks difficult to manage because they use lots of different standards. But from a business point of view it was three sets of information that we could not join together.

Cisco has been working to converge those networks onto a single unified network platform based around IP.

“For most of the time we were doing that looking in the wired network environment. Wireless has been coming along in the last 10 years but until fairly recently it was regarded as a separate environment.
 

In the last few years, though, we have been able to converge both the wired and wireless world such that now we have an ubiquitous single unified network environment comprising both wired and wireless which ultimately means we enable freedom.

Whether a user has a handheld in his pocket or is at his PC or whether he is on holiday he still has access to all of the information and the communication capabilities that the network brings.

“Using the network as a platform, our customers whether they are at management level, engineering level or operator level have access to real-time information, which enables them to make better decisions to avert a safety situation, shutdown or enable them to become more effective and efficient,” Pegler adds.

Emerson and Cisco are not the only firms to have combined forces to develop the potential of wireless technologies.

Motorola’s US $3.9 billion acquisition of Symbol Technologies in 2007 enabled it to extend its product offering to include wireless networks, as Fredrik Uddegard director of field mobility and utilities in the EMEA region for Motorola Enterprise Mobility Business explains: “Motorola has a long history with walkie-talkies, TETRA networks, point-to-point and other business critical voice and data communications and once we could join the offerings from Symbol, namely the wireless LAN offering, we got the full product portfolio.

Unlocking potential

Uddegard says the utility sector is really starting to embrace wireless technologies and the freedoms it brings.

“It is scaling up; all the utilities are doing heavy investments in infrastructure, upgrading networks, the meters in the homes,” he comments.

“They have more and more SCADA systems, surveying the equipment in the power stations and the grid and all of these new technologies rely on the connectivity.

With the return on investment compared to doing the classical cable installations being so fast, it is compelling, and all utilities are focusing on wireless infrastructure now.

Motorola is also very active in the growing area of smart metering and the automatic transfer of billing information.

“One of the key trends that we see in the utility sector is the move to smart metering infrastructure in the whole of the EMEA region,” says Uddegard. “The utilities are doing huge investments in order to deliver more customer service to clients, to be more efficient and also to deliver information to governments in free markets.

“We are not selling the meters themselves but we are partnering with metering companies when it comes to the connectivity and bringing the data to the back office,” he adds.

Wireless technology is not a complete replacement for wires, at least not yet. But the seamless integration of wired and wireless plant and field networks is enabling the true mobilisation of utility providers: an interconnection of workers in the field and office, of customers and business systems and of production equipment, inventory, fleet vehicles and other assets.