Ouch! Having an interference source that is only a slightly longer wavelength than the RFID frequency is a real tough problem. If the bombarders are only interfering with transmits/receives and not actual writing false data to the pallet markers I would suggest altering the system programming to read the pallet while the bombarders are off, and then disable the RFID system during the bombardment process. If the transponders actually are having garbage written to them by the bombarders you need to contact OMRON for help.
Scott Lacey -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Monday, October 15, 2001 2:43 PM To: [email protected] Cc: [email protected] Subject: EMI trouble shoot inquiry Group: I attach an RF interference inquiry from a customer; I have no 'smarts' where RF ID is concerned, so I turn to this august body... ==paste==We have an OMRON RFID data transfer system operating within the same room as 12 RF generators (bombarders). The transmission frequency for the RFID system is 530 kHz and the transmission frequency for the bombarders is 400 kHz. The RFID system works through an antenna embedded in a pallet and a stationary read/write head. The bombarders are positioned on a platform overhead. The normal sequence is for a pallet containing a bulb to move via conveyor to a read/write station where information is taken from and added to the pallet. The pallet is conveyed through several different processes, being read/written on roughly 8 occasions. One of the processes contains an RF generator. We are experiencing problems with the RFID system when the RF generators are on. The read/write system operates properly when the RF generators are off. We have determined that the RF generators are creating an interference that does not allow the RFID to operate properly. Initially, w! e built copper shields in the area of some of the RFID stationary heads. This did not seem to help. We also placed EMI suppressors on the RFID cables(near the read heads). This also was not helpful. I have spoken to a company that suggested the use of Ferrite tiles to absorb the interfering waves. The problem with these tiles is that they are very brittle and difficult to use for shields. The concept sounds good but I don't have much flexibility in where I can place the shields. I am currently trying to use ferrite magnets attached to the copper guards. Any help/suggestions you could give me would be greatly appreciated. ===end paste== Thanks for any suggestions; reply as you see fit. WmFlanigan ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
