BLUEBOX Gen.2 HFM
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2
Operating Features
Supported transponders (or tags) and relative associated functions are
described in annexe A.
In ‘continuous’ mode the
BLUEBOX
is characterized by the coexistence of 2
‘parallel’ and asynchronous activities: the tag identification consisting of a
repetitive inventory of tags through an anticollision loop and the
communication with the ‘host’ system. The ‘continuous’ identification activity
interacts with the communication activity through a buffer that contains the
code of the last identified tags or that is empty indicating the absence of tags.
Due to synchronization and filtering reasons, the buffer is handled for each tag
by a parameter defined as ‘hold time’ same as ‘filter time’ defined below (to be
set in the range of 0 … 99 seconds or 0 ... 99 minutes, default value 1 second)
and allows to extend ‘artificially’ the presence of the tag after it leaves the
antenna’s influence area; this behavior is observable looking at the antenna
led status that is ‘on’ indicating the presence of tag/s and also through the
activation of the digital output channel 1 (if its ‘automatic’ management is
enabled by the flag defined in the general parameters). Through the command
‘data request’ it is possible to get the data contained in the buffer (tag/s ID).
The
BLUEBOX
handles also a 31 elements FIFO queue which is combined with
the ‘filter time’ general parameter (to be set in a range of 0 … 99 seconds or 0
... 99 minutes, default value 1 second) that prevents the queue saturation in
case of a tag ‘continuous’ presence. At the end of each inventory session, for
each indentified tag, the
BLUEBOX
compares it to the list of previous read
transponder/s. If the considered transponder do not belong to the list, it is
defined as ‘new’, its code (tag ID) will be inserted in the queue and the filter
time will be started. Otherwise (the transponder belong to the list), the
BLUEBOX
verifies if the filter time is expired. In this case (the filter time is
expired), the transponder is defined as ‘new’ and will be processed as
described above, otherwise only the filter time will be rearmed. Through the
command ‘queue data request’ and the relative ‘ack’, it is possible to get the
data contained in the queue (tag ID) and unload it.
Every time that a new transponder is identified, the buzzer will be activated for
250ms if its ‘automatic’ management is enabled by the flag defined in the
operating parameters.
In ‘continuous’ mode the
BLUEBOX
can be configured to obtain the behavior
of a ‘spontaneous’ reader that will send a message on the RS232 serial line
and on the Ethernet channel every time that a ‘new’ transponder is identified.
The
BLUEBOX
allows the execution of ‘on request’ functions. During the
execution of these functions, the ‘continuous’ identification activity will be
suspended temporarily; the involved commands are relative to device
configuration and tag read/write specific activities.
If not required, the ‘continuous’ identification activity can be disabled through
a flag defined in the general parameters. In this case, the
BLUEBOX
will only
execute the ‘on request’ commands already defined above.
