User Manual

ThingMagic Nano User Guide 39
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Tag Read Meta Data
In addition to the tag EPC ID resulting from ThingMagic Nano inventory operation, each TagReadData (see
MercuryAPI for code details) contains meta data about how, where and when the tag was read. The
specific meta data available for each tag read is as follows:
Power Management
ThingMagic Nano is designed for power efficiency and offers several power management modes. When
transmitting, the power consumption can be minimized by using the lowest RF power level that meets the
application requirements and powering the module with highest DC input Voltage.
A “Power Mode” setting determines the power consumed during periods that the module is not actively
transmitting. Power Modes - is set in /reader/powerMode.
Tag Read Metadata
Metadata Field Description
Antenna ID The antenna on with the tag was read. When Using a Multiplexer, if appropriately
configured, the Antenna ID entry will contain the logical antenna port of the tag
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.
Read Count The number of times the same tag was read on the same antenna (and,
optionally, with the same embedded data value).
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 different read command invocations.
Tag Data When reading an embedded TagOp is specified for a ReadPlan the
TagReadData will contain the first 128 words of data returned for each tag.
NOTE: Tags with the same TagID but different Tag Data can be considered
unique and each get a Tag Buffer entry if set in the reader
configuration parameter /reader/tagReadData/ uniqueByData. By
default, it is not.
Frequency The frequency on which the tag was read.
Tag Phase Not supported in ThingMagic Nano.
LQI/RSSI The receive signal strength of the tag response in dBm. For duplicate entries, the
user can decide if the meta data represents the first time the tag was seen or
reflects the meta data for the highest RSSI seen.
GPIO Status The signal status (High or Low) of all GPIO pins when tag was read.