Verification and Exception Handling

To make your RFID system successful and effective, it is important to make sure that the exceptions are immediately spotted and then automatically handled. How those exceptions are handled is a critical part of planning a proper RFID network. This is why the business process planning is so critical to the success of an RFID deployment.

Although the tags are tested by the manufacturer and verified by the RFID printers, that does not ensure that they will remain correctly functioning during their entire life cycle. The main reasons why the tags may stop working or cannot be read are as follows:

• Tags are damaged during the application. Reasons could be inattentive or untrained personnel, ESD, or an incorrectly set pressure on the label applicator.

• Tags are placed incorrectly on the product or packaging, and the product detunes the tag. Reasons could be personnel not following placement guidelines, a label applicator set for incorrect label placement, or the product or packaging not having been tested for best label placement.

• Tags are damaged by handling. Handling machinery can damage the tag, as can jams of boxes on the conveyor.

• Tags are incorrectly encoded, or the interrogator expects a different format or coding.

When designing your RFID system, make sure that you have sufficient verification points. Read points with feedback devices should be placed after the tag is applied to a product or packaging and before any intersection in the conveyor system. That way you can maximize the potential of your read point, not only verifying the function of the tag but also using this data for decision making, routing the box either to its destination or to exception processing.

After you choose the location of the verification points, make sure that the alerts and notifications are heard or seen. Use light stacks if you have appropriate personnel to watch them and take action, or sound devices if the verification point is out of sight. Obviously, sound devices will not be useful in high-noise environments. You can also send the alerts through the network to appropriate stations.

Make sure that all alerts are documented. The best way is to create an automated system log that captures information about what happened, the date and time, the person responsible, the problem's resolution, and other useful data. This log can be a valuable source of information for reports about your system and can provide information for managerial decisions.