Readers
5.5 SIMATIC RF685R
SIMATIC RF600
System Manual, 11/2018, J31069-D0171-U001-A21-7618
189
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.
Table 5- 43 Range of antenna depending on antenna gain
Deviation from maximum antenna gain [dBr]
Read/write range [%]
0
100
-3
70
-6
50
-9
35
-12
25
-15
18
-18
13
Example
As can be seen in the section Antenna diagram for RF685R (ETSI) (Page 181), the
maximum antenna gain 0 dB is standardized. In the Azimuth diagram, the antenna gain falls
by 3°dB at approximately ± 39°. This means that 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.
5.5.2.2
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.
