Readers
5.6 SIMATIC RF685R
SIMATIC RF600
System Manual, 06/2019, J31069-D0171-U001-A22-7618
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Interpretation of radiation patterns
The following overview table will help you with the interpretation of 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 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- 52 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 207), 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 70 % of the maximum range at ± 39° from the Z axis within the horizontal plane.
5.6.2.2
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.
