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RFID – Radio Frequency IDentification

Not so long ago, barcodes were introduced -- they were a marvelous innovation, allowing the use of a scanner to read off important information. This was a great time saver, as it eliminated the nee...


February 1, 2005
By Pulp & Paper Canada

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Not so long ago, barcodes were introduced — they were a marvelous innovation, allowing the use of a scanner to read off important information. This was a great time saver, as it eliminated the need for a human to enter information on an item in question — a scanner could send the information directly to a computer in a form it could use. In this way, a store could track the amount of milk brought in and sold. But suppose, instead of a bar code, there was a way that the milk could not only identify itself and its price, but tell whether it is approaching its expiry date or even if it has been stored at an incorrect temperature at any time. That is where RFID chips come in!

RFID and bar codes all come under a general class of Auto ID techniques. These include such as bar codes, smart cards, voice recognition, some biometric technologies (retinal scans, blood vessel patterns), optical character recognition (OCR), and radio frequency identification (RFID). The purpose of any of these is to enable an item, person or device to identify itself without human intervention. This frees people from the drudgery of data entry to do more useful or creative work. Bar codes are a good way to identify the type and manufacturer of an item, but they have limits to the amount of data they can convey. Also, they are line-of-sight, so usually require a human to align the bar code with a scanner. The advantage of a RFID tag is that it cannot be smudged off, obscured by dirt or a misplaced label and can be read at a distance despite intervening obstacles. There are other benefits as well:

* They can carry a large amount of data, up to 2kb — the equivalent of two pages of text.

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* A tag can be combined with sensors to record a variety of conditions, allowing this information to be retrieved later.

* A single reader can track multiple items through a portal.

* They allow real-time inventory control, reporting shipments in and out.

* With an RFID, an item can be uniquely identified –not just as from a manufacturer or even from a batch, but as a unique item.

There are some disadvantages however:

* They are expensive, ranging from a few tags for a dollar to a few dollars per tag.

* Depending upon the frequency, the range can be quite short.

* The signal can be blocked by concrete or metal walls.

* There is a lack of standardization, even within a given country, never mind overseas.

* There are multiple frequencies, formats and styles of tags.

The variations on RFID are based on frequency, type (read-write or read-only) and active vs. passive. The frequency affects the range and penetration of the signal — higher frequency gives longer range, but less penetration. Tags can be read-write, meaning the information they carry can be written over with new data; or read-only, meaning that their information cannot be changed after the initial writing. Active tags have battery power and can be read at very long ranges — 100m or more. Passive tags rely upon the power of the reader’s radio signal and the range is usually less than a meter.

RFID has been around for decades, but expense, technological limitations and the lack of a true (or even perceived) need has prevented wide spread adoption. Wal-Mart has been in the news for insisting that its major suppliers incorporate RFID tags into their packaging at the case or pallet level. Their configuration is a passive, high frequency (915MHz) standard which allows for long distance (7 – 10m) reading. The problem is that this standard is not permitted for markets in Japan or Europe. For an industry like P&P which ships globally, a more widely accepted standard is required. A passive, low frequency configuration is more likely to allow acceptance in distant markets. There have been some experiments made with 13.56MHz tags on paper rolls. These tags were placed on the exterior of the cores to protect the tags from handling equipment, but these need a ‘relief area’ to avoid crushing from the weight of the paper on the roll. Pulp bales would likely use a simple paste-on label which incorporated a tag. A handheld reader would probably need to be within 10cm to read a tag in a roll (these are within a roll core), or up to 1m for the bale tags.

With sufficient sophistication in these tags, a bale or roll could be uniquely identified by mill, date of production, grade, batch test results and even the conditions it has experienced during shipping or storage. However, the cost could be $1 per unit, or more. As with any other new development, no matter how useful they could be, RFID tags will have to prove their worth before they are adopted by industry.

If you have anything to add or would like to suggest another topic, please contact the author. Dan Davies is the application manager at Degussa Canada in bleaching and water chemicals. He can be reached at dan.davies@degussa.com