Time to smarten up

Electrical contractors and service organisations have long since recognised the business opportunities provided by portable appliance testing. Prompted by the introduction of the Electricity At Work Regulations (1989), the need for the regular safety testing of electrical appliances as part of planned maintenance campaigns has become widely recognised.

Instrumentation manufacturers have responded by introducing a wide range of test equipment aimed at making the testing process faster and simpler to complete. One of the major developments in this respect has been the introduction of PAT testers with the ability to scan information from bar codes attached to appliances. The information stored in the bar codes allows the automatic identification of a particular item of equipment. It also enables predefined test codes to be transmitted to the PAT tester, so that the correct tests are carried out for different types of products.

In the retail and packaging industries in recent years, there has been a trend towards the greater use of rf data tags – or smart tags – as an alternative to bar coding. Now, new research and development work undertaken by test equipment manufacturer Seaward Electronic in collaboration with the University of Durham, has focused on how smart tags could bring significant benefits to portable appliance testing.

Smart tags for PAT
Smart tags, or inductively coupled transponders, containing memory and associated control circuitry, remotely store data using radio frequency signals to both communicate with and power the transponder. In their simplest form, as read-only devices, rf tags perform a similar function to that of bar codes.

Rob Kevan, design engineer at Seaward Electronic, explains how smart tag technology is likely to revolutionise the PAT marketplace. "Firstly, simple read-only tags have significant potential as a direct replacement for bar codes in applications where bar codes are not mechanically reliable enough – for example, on industrial hire equipment. In such cases the smart tag provides no extra functionality other than environmental ruggedness – when the equipment is connected to a PAT tester with an appropriate tag reader, the instrument will then be able to read the tags automatically, with no user intervention." However, the latest work to be undertaken takes things much further. "It is the two-way programmable or 'read and write' properties of smart tags that have the most benefits for PAT testing," explains Kevan.

"For example, large memory read/write tags are capable of storing the appliance identity and test codes in standard bar code-type fashion, but have increased memory capacity to allow them to store test results transmitted back onto the product from the PAT tester. As a result, service engineering records or testing undertaken by qa authorities could be updated automatically after each test routine," says Kevan. In addition, memory could also be set aside for the customer to use, for example, to keep asset information such as supplier details and calibration data with the appliance itself.

Seaward has adapted this concept into the use of Smart Wire Tags, which are based on a large memory read/write tag and sufficiently miniaturised to be placed in the end cap of a 20 mm fuse. "The ability to integrate the tag in a special fuse provides a highly effective method of retrofitting smart tag technology into appliances already in use, although the tag could be included in the internal wiring of appliances during manufacture," explains Kevan.

This technology provides the potential for ensuring that a test data record stays with an item of electrical equipment throughout its lifetime. For example, pre-programmed tags incorporated within a product or appliance at the manufacturing stage can be automatically interrogated during any subsequent in-service safety testing routines. "When connected to a test instrument, it will be possible to automatically identify the smart wire tag allowing tests to be carried out, with the results being transmitted to the tag for storage and retrieval at a later date," says Kevan. The storage of successive test results in this way could enable the test engineer to identify any fault trends, gradual deterioration over time or other potential safety dangers.

Already, extended data transmission distances have been achieved by inductively coupling the rf signals through the appliance's power cable and work has been undertaken on the development of suitable tag reader probes capable of meeting the demands posed by the range of electrical equipment capable of incorporating tags.

Seaward is launching two tag products in the immediate future. The RetroTag package is completely backwards compatible with existing Seaward products that currently use bar codes – no firmware update is needed. The tag can replace up to three bar codes; the appliance number and two test codes. The user selects which information to transmit to the tester by the use of a simple toggle switch that cycles through the available information.

A new Protag package has been developed for use with Seaward's SuperNova and Europa PAT safety testers. A firmware upgrade is supplied with the kit. Once a tag is in use, data comparisons between the current and previous test results are displayed to the user, making it easy to spot any instrument degradation that may have occurred and enhancing preventive maintenance schemes.

Complete information on the user and test instrument (user name, serial number, firmware and hardware issue numbers, test dates etc) are stored on the tag – traceability is a key function of the ProTag. Up to 256 memory types are available, allowing larger customers to define the information they wish to store – their own asset management tools can use the tags. For both units the reader is a hand-held unit similar in concept to a bar code wand.

Seaward is now researching ways of using the anti-collision capabilities of the chosen tag technology to track assets around large buildings such as universities, hotels, office blocks, and hospitals. "Using the smart wire technology it should be possible to trace units to defined areas of a building. Theft detection should also be possible with tag portals at exit/entry points," predicts Kevan.

The future of installation testing?
"One of the main difficulties in carrying out testing on electrical circuits in buildings is the need to identify the location and description of the circuit being tested, the parameters laid down by the designer and any details relating to the history of the circuit, including previous test data. As buildings and their electrical circuits become more complex the difficulty of identification increases," explains Kevan. Seaward is now examining the potential of using smart tags to identify different circuits and points within an electrical installation.

Although the use of rf identity tags in itself is not a new innovation – the range of electrical test applications for the technology now being developed by Seaward should help to ensure that considerable benefits can be achieved for test engineers and contractors in the crucial areas of safety, records keeping and speed of testing.