Radio link is key to cutting waste

Radio networks installed at Zeneca’s 101ha Huddersfield works are saving the chemicals giant £800,000 a year in water charges. Demand, boosted by leaks or excessive use, has been cut by 40% from 400m3 to 240m3 an hour. The annual water bill is now £1.2m instead of £2m. The lower power radio installation, supplied by PACS […]

Radio networks installed at Zeneca’s 101ha Huddersfield works are saving the chemicals giant £800,000 a year in water charges. Demand, boosted by leaks or excessive use, has been cut by 40% from 400m3 to 240m3 an hour. The annual water bill is now £1.2m instead of £2m.

The lower power radio installation, supplied by PACS of Eastleigh in Hampshire, has a key role in Zeneca’s five-year drive to improve efficiency.

By next year, most of the 63 cost centres on the site will be linked by radio to a central computer system, giving managers access to comprehensive information on use and performance.

The savings could not have been achieved as easily using traditional hard-wired communications, with its higher set-up costs. Wired systems are inflexible when it becomes necessary to add plant to cope with changing demand for products as cabling is difficult to move or upgrade once installed.

A radio installation costs typically one fifth of a wired system. There is no need to dig trenches, which could be under a road or across someone else’s land, or bury cable that can run into hundreds of miles on a typical industrial site.

For every circuit carrying a control signal there will be at least five carrying monitoring signals and shutdown, alarm and communication circuits.

Radio has brought benefits apart from cost and the flexibility to introduce additional nodes to monitor new or upgraded plant. Battery-powered radio transmitter units (RTUs) can be set up in remote locations to send a continuous stream of data on pumps, valves, and other equipment to a central monitoring station; even small items such as sensors for temperature or flow can be linked quickly and cheaply into the network.

Monthly management reports which formerly took six days to produce now take 1.5 days.

Widespread monitoring of even the lowest status plant gives comprehensive information. New wave bands that can travel through metal help speed up data collection which is 50 times faster than with cable, enabling Zeneca to monitor assets in real time.

Low cost and flexibility allows a system of dual redundancy so if one RTU fails, another takes over.

Now it makes economic sense to monitor even temporary plant and for that purpose Zeneca has dedicated a Land Rover with an RTU on board.

Lower power, greater range

Lower power radio networks range from simple point-to-point links to full LANs and WANs. They operate in the UK lower power telemetry bands of 173MHz VHF and 458MHz UHF. The latter, preferred by the utilities, larger steelworks and refineries, needs a 500mW power source and covers distances up to 20km.

At 173MHz the PACS installation at Zeneca takes an extremely low power input of just 10mW. Perfect for battery operated systems, this band works at distances up to 1km, transmitting and receiving data through obstructions such as tanks and other ironwork as well as buildings and trees. Low power multi-drop networks need to be designed and managed to conserve power where possible.

With the cost of RTUs falling, the technology will move rapidly into other areas such as condition and corrosion monitoring as well as transportation, notably automated baggage handling. It is difficult to put a figure on market values or growth. Mike Brookes, PACS managing director and chairman of the Low Power Radio Association, says prices are tumbling fast, brought about by progressive integration of radio with other technologies using dedicated, high speed chips called ASICs.

Within a year he forecasts a £20 sensor will be on the market with on-board radio for building services management. The technology is available now, but the price is prohibitive.