Balluff BIS U-4A7-082-01C-07-S4 Betriebsanleitung Seite 114

BIS U-4A7-082- _1C-07-S4
Industrial RFID system - Read/write head
8
System integration (continued)
Initial Q-value (expected number of tags)
Parameter-ID: 0x0084 – Subindex 2
UHF-Manager: Menu: Device Settings >
Parameters...> Basic UHF (expected
number of tags)
and
Device Settings > Advanced
parameters... > Air interface (Q-value)
The Q-value is used as a key figure for the number of data
carriers expected in the detection range of the antenna.
The Q-value can be used to optimize the time taken for
data carrier detection. In addition, the detection rate can
decrease if the Q-value is selected too high.
The set Q-value is only used as a start value during
detection and can be optimized by the read/write head.
The following table shows a recommendation for setting
the Q-value, depending on the expected number of data
carriers:
Expected number of data
carriers (approx.)
1
2
5
10
Adjustable values for the Q-value:
Length Permissible
[bits] values
8 1...15
Setting fields that specify the expected number of tags are
always rounded to a number calculated from the Q-value.
30 english
Recommended
Q-value
1
2
3
4
Factory Meaning
setting
4 (Q-value = 4) Number of
expected
data carriers
Max. EPC length
Parameter-ID: 0x0084 – Subindex 3
UHF-Manager: Menu: Device settings > Parameters...
> Read-Write
The parameter Max. EPC length specifies the maximum
number of bytes of the EPC memory area that is
transferred by the read/write head.
If data carriers are read whose EPC is longer than the set
Max. EPC length, the read EPC is limited to the set
number of bytes.
The following maximum EPC lengths can be set:
Length Permissible Factory
[bits] values setting
8 1...2 1 (EPC length
= 12 bytes)
TID length
Parameter-ID: 0x0084 – Subindex 4
UHF-Manager: Menu: Device settings > Parameters...
> Read-Write
The TID length determines how many data words (16 bits)
of the TID are transferred from the data carrier to the read/
write head. If data carriers are read whose TID is greater
than the set TID length, the TID read is limited to the set
number of bytes.
If data carriers are read whose TID is smaller than the set
TID length, the TID is not transmitted to the processor unit.
Adjustable values:
Length Permissible Factory
[bits] values setting
8 1...31 data 4 (4 words
words (8 bytes))
Meaning
Length of
EPC in bytes
Meaning
Number of
data words
(bytes) of the
TID