ThingMagic M5e-Compact User Manual
Page 44
Tag Buffer
44
Functionality of the Embedded Modules
Tag Read Meta Data
Whenever a Tag entry is placed in the buffer, it uses up a single entry with the EPC
section containing the
maximum EPC length
number of bits, regardless of the actual EPC
size of the tag read. The extra bits in the entry are padded with trailing zeros.
After the Read Tag Multiple command finishes, it places all of the found tags into the Tag
buffer, and then returns the number of tags found to the user. Only unique tags read on
each antenna are added to the Tag buffer; none of the entries show repeated Tag EPCs,
except when the same tag is read by both antennas, although repeated reads on an
antenna will cause the Read Count field to be incremented for that tag entry. Multiple Get
Tag Buffer
commands must be sent to read out the Tags. The Tag buffer acts as a First
Meta Data Field
Description
Antenna ID
The antenna on with the tag was read. If the same tag is read
on more than one antenna there will be a tag buffer entry for
each antenna on which the tag was read. When
, if appropriately configured, the Antenna ID entry will
contain the logical antenna port of the tag read.
Read Count
The number of times the tag was read on [Antenna ID].
Protocol ID
Protocol of tag. Only 0x05 (Gen2) is supported.
Timestamp
The time the tag was read, relative to the time the command to
read was issued, in milliseconds. If the Tag Read Meta Data is
not retrieved from the Tag Buffer between read commands
there will be no way to distinguish order of tags read with dif-
ferent read command invocations.
Tag Data
When
with an embedded
is called the Tag Buffer will contain up to 32 bytes
of data returned for each tag entry.
Note:
Tags with the same TagID but different Tag Data
can be considered unique and each get a Tag
Buffer entry if set in
.
By default it is not.
Frequency
The frequency on which the tag was read
RFU
Reserved for Future Use - ThingMagic Only
LQI/RSSI
The receive signal strength of the tag response.