Mounting Of Data Carriers; Correct Setting Of The Transmitting Power - 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)
Application with unknown or changing data carrier
orientation
If it cannot be ensured in an application that data carriers
are always oriented in the same way, or if the orientation of
the data carriers is unknown, then it is recommended that
the working distance be aligned to the weaker axis. In this
case, the orientation of the data carriers is irrelevant.
Fig. 5-10: Circular working distance aligned to vertical antenna axis
Application with stable and known data carrier
alignment
If the data carrier alignment in the application is known and
always the same, the alignment can also be made to the
stronger axis, e.g. if a larger working distance is required.
5.7

Mounting of data carriers

In addition to the orientation of the data carrier and read/
write head, the surface on which a data carrier is mounted
plays an important role. Above all, the carrier material is
decisive in ensuring that the data carrier functions
optimally. Conductive carriers (e.g. metal or ESD
containers) detune the data carrier antenna and can thus
reduce the range or prevent detection altogether. When
selecting data carriers, it is therefore important to ensure
that mounting on conductive carriers is permissible, such
as on-metal tags that are specially designed for mounting
on metal. To reduce the influence of the carrier material,
the data carrier can be mounted with a spacer (see
www.balluff.com) if necessary.
The contents of a carrier also have an influence on the
function of the data carrier. If, for example, a data carrier is
mounted on a transport container with conductive
contents (e.g. screws), this can also reduce the range.
16 english
BIS U-4A7 vertically oriented
(flat side up)
Circular working
distance
Antenna field
Liquids and other materials can also have an effect on the
antenna field or data carrier and reduce the range. This
also includes condensation or similar effects that occur
due to the environment and accumulate on the carrier
material or the data carrier.
To ensure a reliable detection process, it should always be
checked whether the selected data carrier achieves the
desired range in the target application, i.e. with the
selected carrier (transport box, workpiece,...).
5.8

Correct setting of the transmitting power

The transmitting power can be used as a measure of the
energy with which the radio waves are emitted by the
antenna. In simplified terms, it can be said that a higher
transmitting power also results in a higher read/write
range. However, radio waves have the physical property
that they can be reflected by metallic structures. Under
certain circumstances, this can have a negative effect on
the function of the RFID system. In addition, radio waves
can be attenuated by plastics, liquids or other materials.
On the one hand, a lower transmitting power can therefore
be advantageous, but on the other hand, a higher
transmitting power can also be required for reliable
identification (e.g. if several data carriers are located in a
confined space or if data is to be written, which requires
more energy than reading data carriers).
Correct setting of the transmitting power means that the
transmitting power should not be set higher than is
required for reliable detection of the desired data carrier
population. If the mounting situation permits, it is
advantageous to mount the read/write head closer to the
detection location if this allows the transmitting power to
be reduced. This reduces interactions with the environment
and other read/write heads (see chapter 5.10 on
page 18). In addition, energy can also be saved in this
way.
For easy setting of the optimum transmitting power in
single-tag mode, the Auto Setup convenience function can
be used (see chapter 8.3.2 on page 36).
Data carriers with small dimensions (about
1...3 cm) typically have a lower efficiency than
data carriers with large dimensions. The upper
power values (12 dBmERP or 14 dBmEIRP) are
intended more for small data carriers and not to
further increase the range of large data carriers.