User's Manual

Library L100 Reader User's Guide
For each pattern, the transmitting antennas will be read a set number of times. The number of
scans defines the global number of antenna read operations to be performed on each pattern. The
order in which antennas are read is always: Antenna 1 (if selected) and then Antenna 2 (if
selected).
The number of scans is common to all patterns, regardless of the number of antennas selected in
the pattern.
Each pattern is executed for the same length of time regardless of the number of antennas
selected in the pattern.
The duration of each scan period is defined as follows:
• For Reader Talks First (RTF) smart labels, the scanning duration gives the number of Read
commands sent to the tags during a single scan period. (Minimum Recommended Scan
Duration is 20 Read commands)
For RTF tags, L-L100 Reader must send a Read command to tag for it to be read.
• For Tag Talks First (TTF) smart labels, the scanning duration gives the time during which
the reading process is activated on one antenna during a single scan period. (Minimum
Recommended Scan Duration is 100 ms.)
When a TTF tag is detected, the read operation will be completed even if the scan duration
period has expired. In other words, the actual scan duration may be longer when a TTF tag is
processed at the end of the scan period.
For more information about Scan Number and Scan Duration parameters, refer to the example
given in Section 8.5.3, "Enabling each Antenna separately and then both at once".
8.4 3-D Rotating Field Applications
Phase shifts can be used to detect tags in a 3-D rotating field application. Phase shifts of 0°, 90°,
180° or 270° are available.
In this case, both antennas must be enabled (transmitting) simultaneously in order for the two
phases to create a 3-dimensional RF field.
8.5 Pattern Examples
8.5.1 Enabling one Antenna after Another
This is the most common example of a tag-reading pattern and requires the use of two patterns.
The first one enables only Antenna 1, while the second enables only Antenna 2.
In Pattern 1, Antenna 1 is enabled and then the detected tags are read. Afterwards in Pattern 2,
Antenna 1 is disabled, Antenna 2 is enabled and then the detected tags are read.
Channel 1 2
Pattern 1 Enabled Disabled
Pattern 2 Disabled Enabled
28/45 Revision 3.1b April 2003