Continue from Part 2.
Group systems manager David Lloyd said the system produced near perfect accuracy and slashed operator working times. ?It is amazingly accurate,? he says. ?It takes 15 to 20 minutes to train operators in the system and it is then 99.9% accurate. In any stock control system, the keyword is accuracy. The only way this can fail is if the operator puts in the wrong information, but even then everything is recorded so there is an audit trail.
Building on WiFi is Wimax, or IEEE 802.16. At the early stages of adoption, it offers the potential to replace copper in the last mile and to support up to 75Mbit/s over tens of miles. In a few cases, entire cities have achieved WiMax coverage.
Another new kid on the wireless block is Zigbee. Based on the IEEE 802.15.4 standard, access to the specifications is controlled by the Zigbee Alliance. The key benefits are cheapness, simplicity and long battery life when compared with similar personal area network technologies, such as Bluetooth. Transmission range is up to 75m, bandwidth is up to 250kbit/s and nodes can be arranged in star, peer to peer or mesh topologies. The ability for Zigbee units to form mesh networks is seen as a key advantage, because that configuration can reroute should one node go down.
Expectations for Zigbee are high. Market research company Harbor Research says that, by 2008, there will 100million wireless sensors in use, up from about 200,000 today. The worldwide market for wireless sensor networks, it says, will grow from $100m in 2005 to more than $1billion by 2009.
Although expectations are high, we are still at the early stages of adoption, says Tony Lucido, VP of marketing with fabless semiconductor company Jennic, which develops Zigbee microcontrollers.
?Last year was the year of technical evaluation; this is the year of product development,? he says. ?Zigbee?s primary advantage is that it is standards based and ideally suited to low data rate and long battery life. Bluetooth, for example, has a battery life of 100hr, whilst Zigbee has battery life of one or two years. Installation costs are quite low compared to wired technologies where you are dealing with many units.
Zigbee is particularly suited to building automation and to control and monitoring applications in industrial, medical and residential environments. A lot of attention is being placed on development of Zigbee based wireless light switches, blind and window shade controls, thermostats, home security devices, consumer electronics remote controls and medical sensors.
Although it?s early days, there are some industrial Zigbee implementations. In Turkey, for example, a Hugo Boss textiles plant has automated its stock control and production monitoring using RC2200 Zigbee modules from Norwegian Radiocrafts. Zigbee modules ? which have a form factor of 16.5×35.6mm ? are attached to batches of clothing and fixed nodes at sewing and pressing machines register their presence at that stage of production. Management can track order status and productivity, whilst operators can receive instructions instantly. Plans are afoot to capture maintenance and quality data for display on large panels in production areas.
In general, though, Zigbee has yet to gain traction in the mainstream, says John Corbett, sales director with systems supplier Ember. ?It has been gaining round in the past year or two, but we are still in the early adoption phase. Many people are still sitting on the fence to see how things go.
Lucido thinks many will be getting off the fence soon. ?In one or two years, we?ll see a plethora of Zigbee compliant products coming to market and be surprised by the range ? from domestic control of heating, lights and burglar alarms to industrial locations with 1000 nodes using the same underlying technology,? he says.
