Industry makes ready for RFID

Many people already use rfid (Radio frequency IDentification) systems in their everyday life - just think of the key-fob that controls access to your car, or even the smart-card that you swipe to gain entry to your work. These are relatively simple examples of RFID systems, which comprise, in their basic form, of three different components: a 'tag' which is an integrated circuit (IC) containing the RF circuitry, and information to be transmitted; an antennae, which receives signals and transmits information; and a reader to decode and output the information from the tag to another device.

There are two type of tag: passive tags, which draw the power to activate the IC from the signal; and active tags, which contain a battery to power the IC. Tags also come with read-only and read/write capabilities, with data storage capacities of a few thousand bytes. Recent developments in tag technology have led to increased storage and read/write capacities. The introduction of 'smart labels', where IC and antennae are integrated into conventional labels, has opened the possibility for use of RFID into many areas where bar-coding currently dominates as well as bringing the concept of 'smart products' closer to reality - the suite that contains all the details about it's cleaning requirements or the frozen meal that tells the microwave how to cook it!

Of course, there are a number of constraints to the uptake of RFID in various areas. For instance, certain wavelengths (2.4Ghz) are absorbed by water (ie humans) causing read/write problems in some areas. Large amounts of metal near tags cause interference problems, so shielding and positioning of tags becomes important in manufacturing environments, adding to their cost and limiting usefulness. A lack of international agreement about the wavelengths available and the strength of signals allowed is holding back uptake in areas like baggage and parcel handling. Even the cost of tags themselves, though reducing as technology improves and volumes increase, is still three times higher than a conventional baggage tag or a hundred times that of a simple bar-code label.

In terms of manufacturing, there are some existing examples that show the way this technology works, though most are in pilot or proof-of-concept stage. Imagine the production of cars. Not only have we come a long way from the Henry Ford approach of, "You can have any colour you want, so long as it is black", manufacturers must also provide individual options for individual customers within their automated lines - mass customisation in essence.

Opel uses RFID tags to ensure that each vehicle carries that information through the production process. At each assembly station, a read/write device interrogates the tag and instructions are passed to the assembly robot controller 'on-the-fly'. Not only does the tag contain all the information required to identify the components for that particular car, it is also used to carry the monitoring and qualitative information from each assembly stage. This information is written-back to the tag, providing a unique repository of process and quality data on individual vehicles.

Ford uses a similar RFID system in one of its engine plants. The tags contain details about the engine type, the specifications and performance criteria it has to meet, as well as the manufacturing instructions for each work cell. Not only is process data from each work cell recorded on the tag as it goes through the manufacturing process, the results of testing and conformance to emission and other standards are also captured. In both cases, even if the host system that loads the information in the factory crashes, the production line is able to continue working for some time, since all the data necessary to drive assembly is contained on the tag. Taking the concept further, it is possible to envisage that tags attached to each car would contain details about performance and servicing throughout its lifetime, plus recycling and disposal information.

Sorry, but my microwave has emailed me to say that lunch is ready - must rush!

• Cambashi
  d101@industrialnetworking.co.uk