User's Manual

COBALT UHF-SERIES CHAPTER 5: COMMAND PROTOCOLS
PAGE 71 OF 140
5.5.4 CBx Multi-Tag Command Packet Structure
CBx Multi-tag Commands instruct a specified controller to read from or write to
several tags at once when multiple tags are simultaneously within RF range. It is also
possible to single-out and read from or write to one tag (identified by its unique tag ID
number) when multiple tags are present in the RF field simultaneously.
Below is the structure of a basic CBx multi-tag command packet.
CBx Multi-tag Command Packet Structure
WORD # COMMAND PACKET ELEMENT MSB LSB
01 Overall Length
: 2-byte integer value
indicating the number of “
words
” in the
command packet.
0x00 0x08 + (number
of any additional
data words)
02
0xAA
in MSB
Command ID
: LSB value indicates
command to perform
0xAA <Command ID>
03
0x00
in MSB
Node ID
: LSB value indicates the Node ID
number of the controller to which the
command is intended (must be 0x01 for –
Cobalt IND models)
0x00 0x01
04 Timeout Value
: 2-byte integer represents
the maximum length of time allowed for
the completion of the command,
measured in one-millisecond increments,
where 0x0BB8 = 3000 x .001 = 3
seconds. The Timeout Value can have a
value of 0x0001 to 0xFFFE (1 - 65,534
milliseconds).
0x0B 0xB8
05 Start Address
: 2-byte integer indicating
the location of tag memory where a read
or write operation will begin (when
applicable).
<Start MSB> <Start LSB>
06 Block Size
: 2-byte integer indicating the
number of bytes that are to be read from
or written to an RFID tag during the
operation (when applicable).
<Size MSB> <Size LSB>
07 Reserved for future use
0x00 0x00
08 Tag Limit
: Single-byte MSB value for the
maximum # of tags expected in RF range,
up to 100 (see description in Section
1.3.4).
0x00
in LSB
0x64
(100 tags
max Tag
Limit)
0x00