Omron V740 Series Operation Manual page 20

The constraints on the scheduler in the V740 for the
time_out are shown below. Time is equally divided
among the specified protocols, and then divided
among the antennas.
For all protocols except EPC0, the antenna arbitration
algorithm is optimized for the maximizing the read rate
of the tags in the field. For EPC0, at this time, each
antenna will be arbitrated 112ms of search time. Thus,
time division for antennas within a protocol cannot be
specified. It is important in specifying a search to
specify the protocols one is searching on, or else the
Reader will spend time searching for protocols one is
not interested in. For specifying the time to search
over multiple protocols for a single query, it is
important to keep in mind that the time_out parameter
should be specified as the worst case of the multiple
protocols.
minimum time_out =
max{num_epc0*epc0_time_per_tag,num_epc1*ep
c1_time_per_tag,num_iso*num_iso_time_per_tag
,..}x # protocols x # antennas (ms)
e.g. if 40 EPC0 tags takes 1.4 ms per tag and 10
EPC1 takes 16 ms per tag on average. With two
antennas:
minimum time_out =
2 x 2 x max{40*1.4,10*16} = 640 ms.
As another example, if the goal is to search on EPC1
and EPC0 on antennas 1, 2, or 4 for strong 20 tags on
each protocol. The query specified is 'SELECT
read_count, protocol_id, antenna_id, id
FROM tag_id WHERE antenna_id = 1 OR
antenna_id = 2 OR antenna_id = 4'
V740 RFID READER ANTENNA
OPERATION MANUAL
V740 will search 3 protocols for 250 ms:
EPC0, EPC1, and ISO18000-6b will each get a
83.3ms slot. This will allow all 20 EPC0 tags to be
read, but not all EPC1 tags.
If the EPC0 tags are present only on the 4th antenna,
the Reader will never arbitrate time to this antenna. A
better query would be:
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' OR protocol_id='EPC0')
SET time_out=1200
112ms) should read all 20 EPC0 and 20 EPC1.
NOTE. SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.
20 of 27
Both EPC0 and EPC1 will get 600 ms:
each antenna for EPC0 will get 200 ms (above
REV. 1.1
© OMRON CORPORATION 2004