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Why industrial RFID works

RFID technology is making its way into industrial environments, but the applications don’t end there, writes David Ward.

There is a technology wave sweeping Australia: the RFID (radio-frequency identification) one. It is no secret that Australian Industry has a reputation as a ‘testing ground’ for new technologies, and this may or may not be the reason why RFID is growing so rapidly in this country, but the technology is taking hold and growing fast.

“We’ve certainly noticed a landmark trend towards RFID from traditional, steadfast, industrial, barcode identification applications, but a further industrial revolution is now revealing itself. One example of a traditional RFID application is baggage handling systems,” said Fast Automation director and supplier of RFID technology, David Askew.

Baggage tag scanning is a traditional and sizable industry for the barcode technology vendors, and the principal site for Australia is Sydney Airport. Accusort held this crucial technology supply contract for a period, but has recently been overtaken by Datalogic. Sensor giant Sick is now vying hard and is reported to have some new technology that is very competitive. Whoever holds that valuable supply contract claims supremacy in the barcode scanning world. However, these fierce rivals are now facing a new enemy and are grappling to partner it.

RFID benefits

To understand the real benefit in switching to RFID we need to first understand the barcode method as it applies to baggage handling. When one checks in a bag at the airport it is appended a baggage tag with a barcode. There are arrays of typically 10 or 12 barcode scanners or ‘heads’ positioned at key locations; these are referred to as Automatic Tag Readers (ATRs). The quantity of expensive and high-tech laser heads is to ensure a line-of-site fix on the barcode.

This array of heads is usually controlled by a ‘multiplexor’. The multiplexor takes what all the heads read via multiple communication channels and passes it up to a higher-level controller, via a single communications channel. This multiplexor is a critical point of failure and therefore is invariably implemented with a second, expensive Multiplexor for redundancy.

As a bag travels along a conveyor, its baggage tag code is picked up by the ATRs. It is then tracked in PLC memory via Pulse Position Indicators (PPIs); these inform the controller that an amount of belt movement has occurred. Typically, there is a Photo Electric (PE) sensor on each conveyor belt for movement and a verification sensor. The verification sensor compensates for the imperfections in transport (for example, if a bag slips forward or backwards). Using these sensors, and the ATRs in key locations, the bags are tracked through the system with up to 99 per cent accuracy. There are, however, issues that occur with multiple tags, tag priorities and aligning explosive scanning results with bags.

Now, imagine how the RFID implementation works — yes, just scrap the PPI sensors, scrap the PE sensors, scrap the $100,000-plus ATR barcode scanning arrays, all the tracking logic, all the PLC distributed I/O and just put an RFID tag on the bag with readers at decision points. The RFID tag could be updated with data (e.g. explosive scan results) instead of trying to hold them in memory and align them physical bags: a drastic reduction in communications and processing. This one example of a traditional barcode application switching over to RFID is a clear indication that RFID has big advantages and massive cost savings across the board.

Real-world applications

“Another industrial client of ours has really discovered the benefit of RFID; a hot water-heating giant went through the exercise of considering what would happen if the product, while being assembled, had an RFID tag onboard (e.g. it could tell robotic stations what type it was and they automatically adjusted themselves to suit),” said Fast Automation’s Askew.

“Testing stations need to know what heating element is installed, in order to conduct the correct test. The system scans the tag, hits a database, looks up the product’s electrical test parameters, downloads them to the electrical tester for testing and executes the test. It then loads the results onto the tag!

“The product can then be automatically routed directly to the appropriate repair bay if failed. Furthermore, this client is now going to put RFID tags on the components to be fitted for instant quality checking. The RFID tags are even embedded into the floor and scanners on forklifts change speed and pick goods from a mobile touchscreen’s ‘pick-list’ with an integrated guiding map — in other words, inventories are instantly updated.

“The RFID tag is even used to instruct the end-of-line printer what to print, including various test results. Not only does it dispense with all the tracking required, but it transforms the entire operation to another level of efficiency and productivity.”

One of the most iconic theme parks in Australia is now switching to RFID. Luna Park in Sydney has presently implemented a bar-coded wrist-band system. This was a big step forward in its day, and drastically improved operations.

However, inefficiencies in the system (compared to RFID), were immediately apparent. The barcode system could be easily copied, it required the holder to orient and position the wrist-band correctly to the scanner, and the barcode could be defaced.

Therefore, Fast Automation implemented an RFID solution that did not require the costly re-engineering of the whole system, but simply implemented the RFID units to masquerade seamlessly as the previous barcode units. Put simply, only the scanners required replacing, even though Luna Park was seriously considering a costly replacement of the entire system.

“With our low-cost interfacing boards — swapping out barcode scanners with RFID units — we can get the RFID units to communicate in exactly the same way, so it’s a fast, low-cost and low-risk changeover. This is why the take-up rate is so high — it’s just quick and easy,” said Fast Automation’s Askew.

Time, money & safety

Consider the labour and time involved in a typical supermarket: we put the goods in the trolley, put them on the checkout, scan them all one-by-one, put them back in the tolley, and take them to our car. With RFID, you can just walk straight out the store: yes, straight out! This will be a reality when RFID starts to take hold in credit card transactions.

The key benefit of the technology is the RFID tag’s type and cost. The technology is rapidly evolving to meet the ever-changing applications that Australian society demands. For instance, there are ultra-high frequency (UHF) tags which come in the form of long-range, high-temperature tags, low-range tags, printable tags and more, all at ever-reducing prices.

These are just some of the applications of RFID. The ramifications and benefits hyped previously are now materialising in our brave new world. The RFID Tsunami is getting bigger and it’s a very exciting time for the automation industry.

[Paul Schaefer is a partner at Fast Automation.]

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