At a recent conference, Jim Mclean, VP of Samsys, spoke of several issues of RFID
interrogators and experiences from case studies. For example, issues such as the distance from the interrogator to its antenna
need to be managed - antennas furthest away need to be supplied more power compared to ones closer to the interrogator (e.g. using different length cables), so that each antenna finally receives the same amount of power. Another issue he raised is whether or not readers need to be always on. In many cases they cannot be. He cited the example of Metro's trials in Germany. In Germany, readers can only emit RF for 10% of each hour i.e. 6 minutes every hour. Motion sensors are attached to the portals so that when a pallet approaches the reader it is turned on from a suspend mode, and after reading the pallet it is returned to suspend mode. Antennas are angled at dock doors to ensure only tags that are passed through the dock door is read, and not ones just nearby. A light array is used to visually confirm when tags had been correctly read - using a traffic light type system. Jim said this was important to confirm to fork lift truck drivers whether or not it had been a successful read.
In several case studies covered, Jim highlighted some early results. Pacific cycle, a US company supplying bicycles to Wal-Mart and man other retailers, chose to meet Wal-Mart's mandate event though it was not in the top 100 suppliers. It did this because it recognised it would eventually have to do it, and by doing it early they seeked competitive advantage. However, where the average time to load a truck used to be 40 minutes, it actually increased to 2.5 hours with RFID
. Jim cited that this has now significantly reduced as staff become used to the process. Lessons they learned were that at the time tags only had a 78% yield, and faulty tags took at least 5 seconds to deal with - a long and unwanted delay. Due to the metal of the bicycles, Samsys installed a custom antenna
area which gave good read performance despite the large amounts of metal present.