
V01.00 | 2018/10 9
IC
Read/write head
HF: alternating electromagnetic field
Data carrier
Fig.3: Functional Principle of HF RFID
The coupling element in the read/write head generates an electromagnetic AC field. This field
creates a transmission window known as an air interface, in which the data exchange with the
tag takes place. The size of the transmission window depends on the combination of read/write
heads and tags.
Every Turck read/write head can communicate with a number of different Turck tags. To do
this, the read/write head and tags must each work within the same frequency range. Depend-
ing on their power and the frequency in use, the devices have a range of a few millimeters up
to several meters. The specified maximum distance between the read/write heads represents
values measured under laboratory conditions, free from any influences caused by surrounding
materials. Attainable distances may vary due to component tolerances, mounting conditions,
ambient conditions and influences caused by surrounding materials (especially metal and li-
quids).
4.4 Functions and Operating Modes
The devices can be used to read and write passive HF tags in single or multi-tag operation. To
do this, the devices form a transmission zone. The size and expansion of this zone may vary on
account of several conditions, for example the tags used and the application conditions. The
maximum distance permitted between the read/write heads is outlined in the data sheets.
NOTE
During multi-tag operation, only the "Inventory" command is possible.
The devices can be operated in IO-Link mode or in standard I/O mode (SIO mode). In IO-Link
mode, bidirectional IO-Link communication takes place between an IO-Link master and the
read/write heads. To make this possible, the devices are integrated via an IO-Link master at the
control level. The read data or the data to be written is transferred via the IO-Link interface
along with the process data. In addition to the read data, diagnostic and identification mes-
sages can also be requested via IO-Link.
Various device functions can be configured via the IO-Link interface.
In SIO mode, the presence of tags can be polled or the data from two tags can be compared.
The devices can also be programmed using a parameterization tag. In this case, the settings are
transferred from a tag to the read/write head via a read process. Application-specific paramet-
erization tags are available from Turck on request.