Omron V680S-HMD64-PNT User Manual page 101

 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.
The Reader/Writer does not communicate with the RF tag that has completed communication until the
RF tag is out of the communication area.
The Reader/Writer does not communicate with the RF tag once communicated until the following
conditions are satisfied.
•The RF tag goes out of the communication area.
•The Reader/Writer communicates with another RF tag.
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
FIFO Repeat communications cannot be used for communicating with V680-D1KP RF Tags.
When the communications option is "FIFO Repeat", no notice (error response) is sent to the host device even if an RF
Tag missing error or communications error occurs.
Refer to Time Charts in Section 7 Host Communications Specifications for details of Time charts of each communications options.
p.186
Communications start when an operable RF Tag enters the
communications field. The operation of RF Tags that have
normally completed communications is stopped. If the RF
tag that completed communication normally moves out of
the communication area and the reader / writer further
communicates with another RF tag, the RF tag is ready to
communicate again.
FIFO Repeat communications
Response
Communications processing
Waiting for RF Tag Waiting for RF Tag
RF Tag A RF Tag B
Response Response Processing completed.
Waiting for RF Tag
RF Tag C
Section 6
Functions
RFID System
99
User's Manual
(PROFINET)