User's Manual

3-8 Duplicate Communication Protecting Function
3-8
3-11
The Duplicate Communication Protecting Function prevents the command that
processes multiple Tags serially from performing multiple Read/Write processing
for each Tag. This function controls the command so that it performs the
processing only once per Tag and returns a single response, even in situations
where a Tag is recognized more than once as shown below. The processing load is
reduced because the response receiving or duplication check by the host is
unnecessary. The communication performance speed is also improved since
unnecessary processing is eliminated in the following:
1. The situation where the Tag enters the Antenna Communication Area several
times due to its vibration, irregular operation, or stop on the boundary, or because
the Tag is in the antenna’s side lobe area.
2. The situation where the Tag is stopped in the boundary zone or enters the
Antenna Communication Area several times because of the moved antenna.
3. The situation where the Tag passes an antenna with a discontinuous
communication area such as the gate antenna.
The enabled function is activated when the commands using the following
communication modes are executed:
・FIFO Repeat Mode (FR)
・Multiple Trigger Mode (MT)
・Multiple Repeat Mode (MR, UR[I.CODE1 Only]*)
When the function is enabled, the unique number (UID/SNR) given to the
processed Tag is recorded in the table of the processed Tags after the command has
been executed. When a new Tag is detected and its UID/SNR is obtained, the
system refers to the table and processes the Tag only when the UID/SNR is not
found in the table. After the Tag has been processed normally, the system records
the UID/SNR in the table. The table is initialized at the start of command.
* As to UR, the page on which the processing is started must be FB, and the pages
must be 2 and more.
The function is set by the Duplicate Communication Protecting Function Setting
(MX) Command (disabled by factory default.) To enable the function, specify the
maximum number of UID/SNRs recorded in the table of the processed Tags. The
number of tables can be selected from 1, 4, 8, 16, 64, 128, or 256. Usually, the
closest number above the maximum number of Tags that can co-exist in the
communication area of the antenna being used is specified.
Example) When the maximum number of the co-existing Tags are 6: The number
of tables = 8
0
1: Tag０
2: Tag１
3: Tag２
4: Tag３
5: (Vacant)
6: (Vacant)
7: (Vacant)
8: (Vacant)
4
The table of the processed Tags :
In this case, Tag 0 is not processed for re-entry in the communication area. When
the Tag 4 enters the area  it is processed and recorded in row 5: of the table.