Example of an application "optimize antenna position"
The aim is to find the optimum antenna position of an RFID reading point as quickly as
possible. A good antenna position should have a high and stable RSSI value.
The position and alignment of the RFID antennas has a significant influence on the quality of
the read results. For this reason, mounting the antennas is an important step during
commissioning of an RFID reading point. With SIMATIC RF-DIAG it is possible to find the
optimum antenna position and alignment simply and quickly.
The strength of the transponder reply is known as the RSSI value (Received Signal Strength
Indication). The RSSI value can be between 0 and 255. The higher the RSSIvalue, the better
the signal strength. The actual value depends on numerous parameters including the
transponder type, the chip used in the transponder, antenna, transmit power, distance
between antenna and transponder, reflections, noise level in the channels used and in
neighboring channels etc.
In practice, RSSI values of approximately 65 to approximately 115 can be detected with
SIMATIC RF600 readers.
1. Mount the antenna in its approximate position at the selected installation location.
2. Then connect the reader to the commissioning PC with RF-DIAG via the PC adapter and
3. Create a typical identification situation. In other words, position the object including the
4. Set the transmit power to level 0. When necessary, deactivate all additional functions
Operating Manual, 09/2012, C79000-G8976-C292-01
select the "RSSI" tab in the tool.
transponder at the point at which it needs to be identified later during operation.
Make sure there is line-of-sight contact between the antenna and transponder
Make sure that there are no persons or objects between the antenna and the transponder
and that the neighboring antenna fields are deactivated that could otherwise disturb
(Power Ramp, Black List, ITF, Tag Hold, RSSI Threshold etc.). In the factory setting,
these are deactivated.
6.2 Example of an application "optimize antenna position"