Towards a wireless world
Michael Scott on a new control gear and kit to record and transmit dataHeld in New Orleans, the ISA (instrumentation, systems and automation) Show proved a rich source of ideas and trends.
There was much talk about integrating information across enterprises and through supply chains and systems, while the advent of dependable, low-cost wireless will enable previously unfeasible data collection - without replacing existing cabling. Several wireless systems suppliers also offered the facility to collect, store and make data available on the web.
The other notable feature of the show was the way in which measurement and control suppliers courted manufacturing industry, blurring of the interface with the previously dominant process control industry.
The key-note speech was given by H Britton Sanderford Jr, chairman and chief technology officer of Axonn LLC. The company developed relatively inexpensive spread spectrum chip sets with integral batteries. An aerial can be incorporated into the printed circuit board and several manufacturers have already integrated the chip sets into on-line monitors, with no external ariel. Sanderford provided analysis of the security and reliability of this approach to spread spectrum technology and the autonomous nature of its communication - the receiver automatically finds any nearby transmitters. Although the data exchange is fairly limited by some serial communication standards this seems an important piece of enabling technology. Axonn claim more than 5M endpoints in use.
Crossbow Technologies launched a Bluetooth-enabled wireless sensor architecture for real-time remote sensing and data acquisition through 2.4gHz links. Bluetooth is a licence free, low-power wireless personal connectivity standard developed by Ericsson, Nokia, Lucent Technologies, IBM and Toshiba. Already in use in personal digital assistants (PDAs), expect the costs for chip sets to drop to a few $.
Licence free, ultra-reliable wireless ethernet data communications for high interference environments, were being priced at $2,000 (£1,426). One supplier claimed water and waste treatment industry uptake was already significant.
Wireless communications to sensors and on-line measurements is not new, but high costs have meant it has only seen limited use. Despite the lack of agreed standards, wireless has been used for several years for hand-held data capture in manufacturing. The market is still growing for hand-held devices providing two-way monitor and control on the factory floor. Iconics, a developer of web-enabled industrial automation software for Windows, unveiled a small, energy efficient and powerful PDA with radio communications. The product provides extensive facilities aimed at quality managers, production personnel, and maintenance supervisors.
Several manufacturers of on-line process and environmental monitors and miniature dataloggers were showing very low-cost radio systems. One gas detector manufacturer had an embedded radio transmitter, with no price penalty over its competitors non radio alternative. One radio link, to transmit a 4-20mA over one mile, was offered for less than $1,000 (£713), another intended for close quarters data capture from miniature dataloggers was offered at $250 (£178). Xsilogy was offering a battery powered radio system with which 4-20 mA, pulse counter or digital inputs could be transmitted, received over distance of up to half-a-mile, then stored and forwarded to the Xsilogy SkyCentre for internet access. Transmitters cost around $500 (£356) each, plus $10 (£7) per sensor and $200 (£142) per month for data handling. Most other radio offerings were in the $500 (£356) plus region, with prices likely to fall quickly as volume builds up.
The US allocation of radio bands is different to those in Europe but some suppliers are already selling in Europe and the rest all spoke of their plans to follow suit. The debate surrounding the allocation and use of radio wave bands and which radio technologies will dominate continues, but the commercial pressure is so great it seems certain de-facto solutions and standards will quickly develop.
Phoenix DatasComm demonstrated a flexible, easy-to-use remote monitor and control system. The company claimed to be able to integrate data using any or all of the communication techniques available and turn them into web pages. with security, message management and archiving features. Sophisticated data retrieval was vaunted as a strong point.
The development of PDA and radio technology able to read and download instructions to sensors and drives is opening up a significant new market. The PDAs use spread spectrum radio technology and thus make autonomous communications with nearby sensors or other devices. This enables secure audit trails and reduces the need for training. The use of PDAs to calibrate sensors was pioneered by Transmation. It takes only a small leap of imagination to see how wireless PDAs might transform the security and cost of data collection from remote on-line process monitors. Not only can data capture be time and date-stamped but global positioning system (GPS) can be used to position the point of capture. Could this be the end for 'rainy day samples'? In the UK Survey Supplies has already launched a PDA aimed at mapping assets in the water industry.
The water industry faces considerable challenges in obtaining, collecting and collating information from a small number of widely dispersed sites, often with limited resources. Very low-power, spread spectrum radio communication providing web-based data collection and storage appears to offer exciting low cost solution. Tools and services for collecting, collating and archiving data are also promising to reduce the costs of generating useable information.
Utilities have a unique need to monitor and control widely dispersed assets with considerable diurnal variations. The blurring of the manufacturing and process control markets should provide interesting solutions for the complex mixture of single bit and message-rich data flows. The high volumes of PDAs used in manufacturing will provide a blueprint for their use in water treatment and supply. Low cost, long life, miniature dataloggers, smart instruments, and smart drives plus the use of PDAs in 'drive by' mode makes unattended sites even more viable