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7 Ethernet/IP Communications
Using the Once Communications Option, MULTIACCESS ID READ and
MULTIACCESS DATA READ Commands, and a Response Processing
Time that is Longer than the Communications Timeout
EXE
Command code
Command
Command
Area
parameters
Command data
Update counter
response
READY
BUSY
NORM
ERR
Response
Area
Update counter
Error code
Response information
Response data
Communications field
1.
The command code, command parameters, and command data are set from the PLC while the READY sig-
nal is ON. The value of the update counter response is matched with the value of the Update counter in the
V780 response area.
2.
The user (PLC) turns ON the EXE signal. This tells the Reader/Writer to start execution.
3.
When the Reader/Writer receives the instruction to start execution, it turns OFF the READY signal and turns
ON the BUSY signal.
4.
When the Reader/Writer detects an RF Tag and communications end normally, it sets the error code,
response information, and response data, adds 1 (increments) to the update counter value, and then turns
ON the NORM signal.
5.
The user (PLC) detects a change in the update counter value, confirms that the NORM signal has turned
ON, and acquires the response data. After the acquisition of data, the user (PLC) updates the update
counter response value in accordance with the value of the Update counter in the V780 response area. In
addition, if another RF Tag data is responded, the update counter of the Reader/Writer is again incremented.
Therefore, at that time, the user (PLC) acquires the response data and updates the update counter response
value.
6.
When the Reader/Writer detects a communications timeout, it ends the communications with the RF Tag.
7.
When the Reader/Writer finishes returning the entire response data, it turns OFF the BUSY signal.
8.
Once the user (PLC) detects that the BUSY signal of the Reader/Writer has turned OFF, it turns OFF the
EXE signal, and stops the execution of the command.
9.
When the Reader/Writer detects that the EXE signal has turned OFF, it turns OFF the NORM signal, clears
the update counter, and turns ON the READY signal.
7 - 76
0000 hex
RF communication
timeout
0000 hex
0001 hex
RF Tag A
RF Tag B
RF Tag C
1 2 3
4
UHF RFID System V780-series Reader/Writer User's Manual (EtherNet/IP
0001 hex
0002 hex
0002 hex
0003 hex
5
6
7
0003 hex
0000 hex
8
9
TM
) (Z402)
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