Siemens SIMATIC RF600 Series System Manual page 163

Interpretation of directional radiation patterns
The following overview table will help you with the interpretation of directional radiation
patterns.
The table shows which dBi values correspond to which read/write ranges (in %): You can
read the radiated power depending on the reference angle from the directional radiation
patterns, and thus obtain information on the read/write range with this reference angle with
regard to a transponder.
The dBr values correspond to the difference between the maximum dBi value and a second
dBi value.
Deviation from maximum antenna gain [dBr]
0
-3
-6
-9
-12
-15
-18
Example
As can be seen in the section Antenna diagram for RF685R (ETSI) (Page 155), the
maximum antenna gain 0 dB is standardized. In the Azimuth diagram, the antenna gain falls
by 3°dB at approximately ± 39°. Therefore the dBr value is -3. The antenna range is only
50% of the maximum range at ± 39° from the Z axis within the horizontal plane.
Antenna/read point configurations
The RF685R reader has a switchable antenna (circular or linear polarization). You can cover
one read point with this antenna. When several RF685R readers are used, the readers are
addressed via the SIMATIC level.
5.4.2.2 External antenna
Preassembled standard cables in lengths of 1 m, 3 m, 5 m, 10 m, 15 m, 20 m and 40 m are
available to connect the antenna.
The read range is limited by the cable loss. The maximum range can be achieved with the
cable 6GT2815-0BH10 (length 1 m) since this has the lowest cable loss.
Examples of possible antenna reading point configurations
● A data source with an external antenna for a reading point.
● As an alternative, a data source with an internal antenna for a reading point.
SIMATIC RF600
System Manual, 10/2016, J31069-D0171-U001-A19-7618
Read/write range [%]
100
70
50
35
25
18
13
Readers
5.4 RF685R reader
163