Omron V780 Series, Руководство пользователя

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7 Modbus/TCP Communications
7 - 14 UHF RFID System V780-series Reader/Writer User’s Manual (Z389)
When you send an RF Tag communications command with single-access communications, the
Reader/Writer communicates with only one RF Tag in the communications range.
With a normal command, the maximum size of data that you can read from an RF Tag is 120 words. To
read more data than that, you must use more than one DATA READ or DATA WRITE command, or use
an expanded command.
If communications with an RF Tag are not possible, a “failure in slave device” exception code (04 hex)
is returned in an error response. Following the error response reception procedure.
7-4-3 RF Tag Communications Command Procedure for Single-access
Communications
Using a Normal Command (FC03 or FC16)
Host device
(client)
Reader/Writer
(server)
RF Tag A
RF Tag A
Command
execution
Command
execution
DATA READ communications
command sent.
Communications range
RF Tag memory
read/written.
RF Tag memory
read/written.
DATA WRITE communications
command sent.
Read data (120 words max.)
Data to write (120 words max.)
Response returned.
Response returned.
Host device
(client)
Reader/Writer
(server)
Command
execution
DATA READ communications
command sent.
Communications range
GET MOST RECENT ERROR INFORMATION
command sent.
Exception code: Failure in slave device
Error code: RF Tag missing error
Response returned.
Timeout (TMO)
Error information returned.