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V740 RFID READER ANTENNA
NOTE. SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE. REV. 1.1
OPERATION MANUAL
19 of 27
© OMRON CORPORATION 2004
DECLARE cursorname
CURSOR FOR query
cursorname
— an arbitrary string.
query
— a SQL query (SELECT/UPDATE
statement), as defined above.
Example:
DECLARE cursor1 CURSOR FOR SELECT id,
antenna_id FROM tag_id;
DECLARE cursor2 CURSOR FOR UPDATE
tag_data SET data=0xFEDCBA9876543210;
One of the advantages of multiple cursors is that it
allows one to specify unequal times for different
protocols. To give 900 ms to EPC1 and 300 ms to
EPC0 in a 1200 ms search do the following:
DECLARE c1 CURSOR FOR SELECT
read_count, protocol_id, antenna_id,
id FROM tag_id WHERE (antenna_id = 1
OR antenna_id = 2 OR antenna_id = 4)
AND protocol_id='CC915' SET
time_out=900;
DECLARE c2 CURSOR FOR SELECT
read_count, protocol_id, antenna_id,
id FROM tag_id WHERE(antenna_id = 1
OR antenna_id = 3 OR antenna_id = 4)
AND protocol_id='EPC0' SET
time_out=300;
SET AUTO c1,c2 = on;
Fetch
To execute the saved query associated with a cursor,
the client software sends the FETCH command.
FETCH cursorlist;
which performs all actions appropriate to the declared
query and sends the result back.
Example:
FETCH cursor1, cursor2;
Auto Mode
In addition to executing a cursor once with the FETCH
command, the client software may also switch the
Reader into Auto Mode, causing it to repeatedly
execute a cursor indefinitely.
SET auto cursorlist = ON, repeat =
interval;
For example,
DECLARE c CURSOR FOR SELECT id,
antenna_id FROM tag_id SET
time_out=250;
SET auto c = ON, repeat = 500;
Every 500 milliseconds, the Reader spends 250
milliseconds querying for tags. The remaining 250
milliseconds are spent with RF off. This syntax can be
used for controlling the duty cycle of the Reader. For
full Reader utilization, ensure that the value of
time_out is no less than the value of
repeat
.
The repeated queries can be terminated by sending
the command:
SET auto = OFF;
No other command can be used while Auto Mode is
active.
Close
To close a cursor and free its resources (only 16
cursors may be defined simultaneously). Only one
cursor can be freed at a time. The client software
issues the command:
CLOSE cursorname;
Reset
To reset the Reader RQL server, for example, if the
RQL state is undefined or questionable, use:
RESET;
The command returns the RQL daemon to its initial
state; that is, no cursors are defined and no data has
been read from the field.
Timeout
The client software can impose a time limit on a read
operation, requesting the Reader to search only for a
limited time (specified in milliseconds). The Reader
may fail to detect some tags if insufficient time is
allocated to the search operation. The time_out is the
parameter used for changing the function of a Reader
and indicates assumptions about the role of the
Reader.
In general, a large time_out should be used for pallets
(>2s), and short time_outs should be used for
conveyor belts (<100ms).
SELECT id FROM tag_id SET
time_out=1000;