Channel Selection/Frequency Hopping; Data Carrier Selection; Ambient Conditions - Balluff BIS U-4A7-082-01C-07-S4 Betriebsanleitung

BIS U-4A7-082- _1C-07-S4
Industrial RFID system - Read/write head
5
Application planning (continued)
5.4

Channel selection/frequency hopping

As described in chapter 5.3 on page 13, when several
read/write heads are operated in a confined space, mutual
interference can occur if they transmit and receive at the
same time. In addition to the spatial orientation of the read/
write heads or the reduction of the transmitting power, it is
also possible to decouple neighboring devices via the
channels (frequencies) used with direct channel selection
(e.g. ETSI variant) or frequency hopping procedures (e.g.
FCC variant).
The availability of channel selection or frequency
hopping depends on the country variant of the
BIS U-4A7 used.
Channel selection
Several channels (frequencies) are available for channel
selection, which can be selected individually. For example,
the ETSI channels 4, 7, 10 and 13 are available for the EU
country version (see parameters Active channels on
page 33). Decoupling is performed in such a way that
neighboring devices operate on channels that are as far
away as possible.
Channel 4 Channel 13
Fig. 5-7: Channel selection
Frequency hopping
With the frequency hopping method, there is usually a
fixed number of active channels available which are
selected at random by a software algorithm. The selected
channels are then only active for a short time before
switching to another channel by means of repeated
frequency hopping. It is assumed that neighboring devices
rarely operate on closely spaced channels at the same
time. As a result, decoupling is achieved automatically via
the selected channels.
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5.5

Data carrier selection

Data carriers come in a wide variety of shapes and sizes.
Simple adhesive labels, robust high-temperature data
carriers with IP67 protection class or small on-metal tags
for mounting on metal carriers. There are also differences
in the memory areas. Since this is also a cost factor, the
following features should be taken into account:
– Memory areas
– Content, type and material of the carrier
–

Ambient conditions

– Read/write range
Memory areas
Common UHF data carriers usually include the EPC, TID,
USER (and RESERVED) memory areas.
The memory size of the individual areas can vary from data
carrier to data carrier. Therefore, preliminary considerations
should be made to determine which data is to be written
to or read from the data carrier.
For simple identification, i.e. to check whether an object
with a data carrier is in the detection range, the EPC or TID
range is sufficient. A large USER data area is not absolutely
necessary for this.
If, on the other hand, a data carrier is to contain individual
information about an object, this could be written to the
Channel 4
USER area. Depending on the amount of data, care should
then be taken to ensure that this memory area can hold all
the required data.
Content, type and material of the carrier
Form factor and size may be dictated by the mounting
support under certain circumstances. For example, by the
mounting space available or the preferred mounting
method, e.g. screwing, gluing, etc. The material of the
carrier (workpiece, container, tray, mesh box, etc.) or its
contents should also be taken into account. For example,
if the carrier material and the contents of the carrier do not
contain metal, the decision can be made freely. Otherwise,
for example, data carriers should be selected which can
be provided with spacers or are approved for use with
metal (e.g. on-metal tags, see chapter 5.6 on page 15).
Ambient conditions
Wherever moisture and mechanical stress are not an issue,
inexpensive adhesive labels can be used. Otherwise, data
carriers with a robust housing and a higher protection
class (e.g. IP67) should be chosen. In an environment
where, for example, cleaning agents or paints are used,
care should be taken to ensure that the data carriers are
chemically resistant. The ambient temperature must also
be taken into account. This is particularly important when
data carriers pass through high-temperature areas within a
production line, for example, and still have a considerable
amount of residual heat at the reading point. Balluff high-
temperature tags, for example, can be used for this
application.