Fit RFID to Your Needs

In a manufacturing facility, for example, individual cutting tools can be identified and monitored for wear so that they can be used for their full expected life but be replaced before they break and ruin the piece being machined.

You might assume that the item’s own serial number should be adequate for this purpose but unless a code assignment authority and vendor code is also stipulated, the serial number itself is often not unique.

The purpose of IUID is not just asset identification and tracking. Its use for financial management is as important if not more important. An IUID pointing to a database entry with date of acquisition, cost, maintenance history and other relevant attributes allows tighter financial accountability and control.

And an IUID is at the heart of all of the preceding applications.

Lessons Learned

In most cases, lessons learned are negative examples. We often learn more when we get smacked in the head than when we get a pat on the back. It’s just the way things are.

Some may be familiar with “The 10 Commandments of Bar Codes” from a number of years ago. Here is a somewhat similar list, “The 7 Deadly Sins of RFID System Design and Implementation”:

1. Dumb Implementation

The adage that applying automation to a bad business process only gets you more useless information faster is doubly true for RFID. It refers not only to automating existing bad processes but also to bad processes developed for RFID.

We all probably understand the idea of automating existing bad processes but here’s an example of a bad process developed specifically for an RFID implementation. The company wanted to use RFID readers on lift trucks to record storage location during pick/put away operations. The vendor recommended using a photo-detector to trigger the reader when the pallet was in close proximity to the rack location. The customer insisted that that was “too complicated and just one more thing to break.” And they figured that reading every tag in every location in proximity to the intended storage location would be a good way to validate data already in their database. The system was a spectacular failure. The lift truck’s mobile computer continually crashed, overwhelmed by the tremendous volume of useless information the customer insisted on collecting. And, rather than use photo-detectors to trigger the reader, the company abandoned the project and blamed the vendor’s equipment.

So the first caveat is, “Know the limitations of the equipment you’ve selected.” The second caveat is, “Don’t let bad management decisions drive RFID system design and implementation.”

2. Assuming You Know Enough about RFID

RFID is not always predictable. Sometimes tags don’t have the read range you want; sometimes their range is too great. Companies have learned they need to shield RFID readers at dock doors to prevent them from reading RFID tags at an adjacent door. That kind of behavior can be predicted. What’s usually not expected is that a facility’s air ducts can channel RFID signals a long way and result in spurious reads.

Tag placement can also be an issue. Whereas standards groups spent years getting companies to place bar codes in specific locations, the same is not so true for RFID. A tag placed over a metal container or one containing certain liquids has a reduced range. Placing the tag over the natural void between cylindrical containers in a carton avoids this. Therefore, it’s often necessary to develop placement standards based on the carton’s contents.

It’s also necessary to get past the “non-line-of-sight” statement concerning RFID. It is usually not possible to read “captive” cartons (that is, with no visible edge) on a pallet. You need to read the tags as the pallet is built, not after.

3. Assuming You Have a “Closed System”

Most of the success stories above could be called closed systems. But it can be argued that, as RFID implementation increases, there is no such thing as a closed system. By their very nature, RFID tags are “promiscuous”—that is, they’re intended to be read by any appropriate reader. Thus, while your intent may be to read only your own tags, there may be other tags from other companies’ “closed systems” that enter your system with similar or even identical data.