Flag persistence rules, Session 0 – ThingMagic M5e-Compact User Manual
Page 78
Application Tag Commands
78
Command Set
– The SL flag must be asserted
– The Session flag (Target setting) for session 0, 1, 2, or 3 (specific Session value is
in the Query and depends on the reader’s Session setting) must be in the user
defined state (the default value is ‘A’).
3.
Matching tags will respond to the Query, but after responding, will change their own
state in the following way:
– The Inventory flag corresponding to the Session specified in the Query will be
changed to the opposite state (A->B or B->A).
– The SL flag will remain asserted (per its ongoing
4.
If subsequent indentical Queries are issued (identical to the first), this tag will remain
silent until the
for the inventory flag that was put into the ‘B’
state cause the flag to fall back into the ‘A’ state or vice-versa. At that point, the tag
will respond again (assuming that the persistence rules of the SL flag are still keeping
it in the ‘assert’ state). Unless the Target Value was set to search for A then B or B
then A, in which case tags will be re-inventoried when the reader changes the flag
value its searching for instead of waiting for the tag to put its tag back into the
opposite state.
Note
A search with Invert=1 specified will perform the same steps except in step
1 the tag will “de-assert if its contents matches that specified in the request
(and, conversely, assert the SL flag if it does not match) as defined by the
Note
A Select will be performed once per antenna when Select is specified during
a
with multiple antennas configured.
Flag Persistence Rules
Session 0
Keeps state as long as tag is energized
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.