User Guide

Gen2 Tag Commands
103
Returns to default state as soon as the tag is no longer energized
Its state will often get reset during the course of executing a single command, for
example, between inventory rounds, or when there is a frequency hop, or when a new
antenna is selected during a Read Tag Multiple search. the result is that when the
session is set to ‘0’, all tags will respond to every appropriate Query, considerably
lengthening the time to inventory a large population of tags. Session 0 is typically used for
operations where a single tag is expected to be in the field, for example, printers.
Session 1
Keeps its state between 0.5 and 5 seconds, regardless of whether the tag is
energized or not.
The intent is that when the session is set to 1 the tag will respond to an appropriate Query
immediately, and then respond periodically if the Query is repeated by the reader. This
allows a larger population of tags to be reliable read. Session 1 is typically used in
applications where a large population of tags is being continuously inventoried allowing
for it to be determined when tags enter and leave the field.
Session 2, 3 and SL Flags
Keeps state as long as the tag is energized.
Keeps its state for at least 2 seconds after the tag is no longer energized and will
refresh its state if the tag is re-energized during that period.
The intent is that when the session is set to ‘2’ or ‘3’ a tag will only respond once to an
appropriate Query, then remain silent as the Query is repeated by the reader to elicit
responses from other tags. Typically used in operations when you are performing an
action on tag or population of tags which you do not want/need repeated.
Operations supporting Tag Singulation/Select
The commands currently supporting tag singulation through Select are:
Read Tag Single (21h)
Read Tag Multiple (22h)
Write Tag Data (24h)
Lock Tag (25h)
Kill Tag (26h)