User's Manual

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7 Modbus/TCP Communications
UHF RFID System V780-series Reader/Writer User’s Manual (Z389)
7-6 V780 Command Details
7
7-6-3 Modbus Expansion Communications Commands
 Function
This command reads the IDs (EPC codes) of multiple RF Tags in the communications field.
You can get the IDs (EPC codes) of more than one RF Tag with one EXTENDED MULTIACCESS ID
READ command.
 Command Format
 Response Formats
• Normal Response or Error Response: RF Tag Communications Error
EXTENDED MULTIACCESS ID READ
Byte-0 Byte-1 Byte-2 Byte-3 Byte-4 Byte-5 Byte-6 Byte-7 Byte-8 Byte-9 Byte-10 Byte-11
Transaction identi-
fier
Protocol identifier Field length Unit
identifier
Function
code
Subfunction code Options
X X 0000 hex 0006 hex FF hex 64 hex 0003 hex 2 bytes
Parameter Description
Subfunction code 0003 hex: EXTENDED MULTIACCESS ID READ
Options For details, refer to 7-3 RF Communications Command Options on page 7-9.
Byte-0 Byte-1 Byte-2 Byte-3 Byte-4 Byte-5 Byte-6 Byte-7 Byte-8 Byte-9 Byte-10 Byte-11
Transaction identi-
fier
Protocol identifier Field length Unit
identifier
Function
code
Subfunction code Number of RF
Ta g s ( m)
X X 0000 hex 2 bytes FF hex 64 hex 0003 hex 0000 to 0040 hex
Byte-12 ...
Byte-12 +
n - 1
...
Byte-12+n
*(m-1)
...
Byte-12+(
n*m)-1
Information from RF Tag 1 ... Information from RF Tag m
n = 66 to 68 bytes ... n = 66 to 68 bytes
Information from RF Tag x
Error code StoredPC EPC code Options
Reception level
2 bytes 2 bytes 62 bytes 2 bytes
Parameter Description
Field length 0048 to 0F86 hex + (Option size × m)
• For details on option sizes, refer to 7-3 RF Communications Command
Options on page 7-9.
Number of RF Tags Gives the number of RF Tags that were detected in 4-digit decimal.
0000 to 0040 hex (0 to 64)
Information
from RF Tag
1
Error code For details, refer to ?9-2-1 ?????? (P.9-3)?.
StoredPC Gives the StoredPC data in 4-digit hexadecimal.
The upper 5 bits are the EPC word length.
EPC code Gives the Tag-specific information according to Gen2 standards.
All bytes of the EPC code section that exceed the EPC word length in the
StoredPC are filled with 00 hex.
Options These parameters may be omitted depending on the option value.
Recep-
tion
level
The reception level is attached in signed 4-digit hexadecimal.
FFFF to FF9D hex (-1 to -99 [dBm])