Omron V680S Series User Manual page 37

 FIFO Repeat
When the Reader/Writer receives a command execution request from the host device, it automatically
detects RF Tags in the communications field and communicates with them. After successfully
communicating with an RF Tag once, operation for that RF Tag is stopped. This process is repeated
until the execution request is cleared. Communications are not performed for RF Tags that have
returned communications results to the host device until the RF Tags leave the communications field.
You can use the FIFO Repeat communications option to perform communications with RF Tags in
order as they move past the Reader/Writer even when there is limited space between the RF Tags. If
there is more than one RF Tag for which operation is possible in the communications field of the
Antenna at the same time, normal communications will not be possible. Make sure that there is never
more than one RF Tag for which operation is possible in the communications field of the Antenna at the
same time.
RF Tag
Reader/Writer
Host device Reader/Writer
Host device Reader/Writer
Reader/Writer RF Tag
RF Tag operation
Communications start when an operable RF Tag enters the
communications field. The operation of RF Tags that have
normally completed communications is stopped. When the
RF Tag moves outside of the communications field, the
operation stopped status is released.
FIFO Repeat communications
Response
Communications processing
Waiting for RF Tag
Waiting for RF Tag
RF Tag B
RF Tag A
Names and Functions of Components
Response Response Processing completed.
Waiting for RF Tag
RF Tag C
Section 2
RFID System
35
User's Manual
(PROFINET)