Staffan Gunnarsson is the Managing Director of TAGMASTER Sweden.

Microwave ID pays off in the distribution chain

Auto ID in the distribution chain leads to less capital tie up in materials, improved planning flexibility, less work force need and fewer faults. Microwaves provide the best alternative when large and valuable objects like containers, palettes, trucks etc. are to be identified, especially if the object speed is high and the environment is dirty. Newer microwave systems are often competitive to optical solutions, and are seen in applications all the way from factory automation to garbage handling, It is easy to find cases where the investment pays off in less than a year.

Range and speed

2,45 GHz microwave ID systems, like the CONFIDENTTM system from TagMaster AB in Sweden, typically read at 4 m distance even through dirt, glass, wood etc., also if passing by at vehicle speed. The excellent range and speed characteristics are important to make a perfectly operating system.

Programmable tags and networks

Microwave tags can be programmable or read-only. Programmable tags make it possible to bring the freight data (article codes, quantities etc.) with the object for stand-alone applications that operate independently of wide geographical area data networks. Network cost and availability are however dropping dramatically these days, and freight companies tend to use read-only tags with readers connected to the Internet/Intranet for transfer of the freight data via email. Both solutions give the mentioned benefits, and it is up to the user to decide whether to use read-only or programmable tags.

Precise shipping

Automatic identification is especially important when the transportation object will be out of reach for a long time, e.g. when it will be transported on ships. By reading the tagged objects when they pass into the ship, and when they are unloaded, the shipping company can give precise information to its customers to the benefit of everybody.

Synchronised factories

Another distribution area is where factories have to be synchronised, such as car manufacturers that buy in seats, dashboards, engines and other advanced components from specialised factories. These objects usually take as long to manufacture as it takes to make the entire car, and furthermore these specialised factories are often so far away that the transport takes several days. Auto ID in the line and at the supplier's factory exit then provides the logistics solution for synchronisation.

Thanks to their long reading range microwave tags can also give automatic access to the supplier's and customer's sites for the trucks, to improve the security and unload guards. Modern microwave ID systems can read multiple tags in the zone and makes it possible to use separate tags for the vehicle/load and for the driver. This way the system can also be used for workforce planning.

Unmanned factories

The process industry often operates with little staff and around the hour. By automatic ID and weighing of the distribution vehicles when entering and exiting the plant, a fully unmanned customer debiting is possible. CONFIDENT is often used in this way, e.g. in cement factories. Thanks to the automatic identification, a display at the entrance automatically guides the cement truck driver to the right loading point, thereby avoiding queues and eliminating the risk that the wrong grade of cement is loaded into the truck. When exiting, automatic correlation of the identity and weight increase of the truck provides the necessary information for the automatic billing.

Microwaves serve the environment

When consumables are about to reach the end destination, i.e. the waste dump, microwave identification has proven to be valuable. Due to environmental restrictions, most waste dumps serve a very large area covering many different communities. To organise the debiting of each community in relation to how much waste that is delivered to the waste dump, long range and high speed microwave identification of the garbage trucks when they enter the waste dump provides an automatic tool for the debiting. As with the cement trucks, the system can also be used to direct the drivers to certain locations at the dump to avoid queues. In sites where the waste is burned for energy, the truck ID also provides clearing of energy value according to the load delivered.

Retail applications

There are also other ways the microwaves can be serve in distribution and retail. One example is in food distribution centres where the dispatch manager gets information each time a truck enters, to organise a new load and assign a load gate while the truck is cleaned after the previous run.

In warehouses, forklift trucks can read tagged palettes to make sure they move the right load, and automatically guided vehicles can find their way by reading tags at strategic locations.

In department stores, multitag reading systems can monitor high value assets on display, such as computers, stereo amplifiers etc. After the objects have been tagged, a hidden reader in the ceiling monitors the objects and gives alarm if they are improperly removed.

Car manufacturing and distribution

Many car factories use microwave ID to control the manufacturing lines, and today at least every third car built in Europe is identified by microwaves. When the cars are to be sent overseas, a temporary tag on the dashboard could be automatically read by microwave readers at the factory exit, at the shipping harbour and at the destination harbour as described before. Today, slow and labour intensive bar-code scanning is often used.

Visible benefits

As described, microwave identification provide clearly visible cost reductions for the manufacturers, their freight companies and customers. Extra benefits are reduced irritation thanks to elimination of mistakes and boring work tasks, as well as improved security and labour planning through combination with automatic access control for the distribution vehicles.

2,45 GHz is international

In global distribution systems, like for air and sea freight, it is mandatory to use an ID technology that conforms to the local regulations on the different continents. The 2,45 GHz frequency is internationally approved for use with automatic identification, but few ID systems are designed to cope with the strict regulations that authorities are setting up to manage the frequency spectrum in view of the ever increasing need for interference free transmission of data.

Global standardisation is coming

In analogy with other media, like mag-strip cards and bar-codes, the microwave ID tag market would benefit from a common standard where readers of different brands can read each other's tags. It is pleasing to see that major microwave ID manufacturers are getting together with the ambition to formulate such a common standard. In analogy with the standardised GSM mobile phone technology, the experts now know the technology well enough to formulate a standard.

A modern design

A modern microwave based identification system has a modular architecture with read-write as well as read-only tags, reads multiple tags in the zone, can handle many readers close to one another without interference, and has a reading range that is electronically adjustable for each installation. Read/write stations have an open software design to make it possible for systems integrators and customers to implement any communication protocol or database function, and the mechanics is prepared to house different communications boards.

Both readers and tags are of all weather design, with corrosion free materials and proper sealing that stand salt water and other humidity. The tags can operate in metal and dirty environments without influence on the reliability, and need in many cases to be read regardless of their orientation.

To obtain their long reading range, all microwave systems that meet the emission regulations use an energy cell for locally powering the tag. Modern tags have such a low current consumption that they can be activate all the time and still last for up to 10 years, in difference to older tags that shifted between a low current "sleep" mode and a high current "active" mode. Consequently, there is no risk that the cells of modern tags are emptied by interference that unintentionally may wake up the tag.

A modern auto ID system uses 32 bit checksums for the tag data to avoid that, under no circumstances, a reading error is undetected (this error type is called "substitution error"). If read- write tags are used, dual memories are used to avoid that old tag data is lost if a tag by accident is brought out from the writing zone while being programmed. A "failed write" bit is then set in the tag, to make sure that an unsuccessful programming is detected next time the tag is read.

TagMaster AB

TagMaster AB is a public company that is located in the high-tech technology park Electrum in Kista north of Stockholm. The company was founded in 1994 by people with more than 10 years of experience from microwave based identification systems, and has distributors and OEM partners that cover most industrial countries. CONFIDENT is a registered trademark under the rights of TagMaster AB, and the system is protected by a range of patents.

Staffan Gunnarsson,December 1996

Tagmaster AB - CONFIDENT microwave tags

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