OBID
i-scan
®
Application-Note
ID ISC.ANT800/600-DA
FEIG ELECTRONIC GmbH
Seite 19 von 26
N50101-0e-ID-B.doc
Possible error sources when tuning the antennas are listed in Table 12:
Table 12: Error sources when tuning
Error
Cause /
Solution
Communication with the an-
tenna tuner is not possible.
Error message:
FEFU: Timeout
-
no power supply on DAT from the Multiplexer
check the power supply (LED on selected antenna tuner and
multiplexer is flashing)
-
cables are not connected correctly
check the cable connections
-
RF-power to low
minimum RF-power (CFG3) 2W
Antenna can’t be tuned, i.e.,
values for difference resistance
and/or phase are outside the
tolerance range
-
Capacitor presets are incorrect. This will be indicated by the
fact that the extreme values 0 or 127 respectively for
Capacitance 1 and Capacitance 2 were set. The cause may
be a strong detuning of the antennas due to the presence of
metal, etc.
For presetting the antenna tuner ID ISC.DAT see
and user’s guide for ID ISC.DAT (M40401-xde-
ID-B)
-
Coupling of the antennas between each other is too strong.
The coupling may be very strong due to insufficient distance
between the antennas or by the presence of metal or ferrous
material in the field.
Increase the distance between the antennas and/or metal or
remove ferrous materials from the antenna field.
3.6. Checking the Standing Wave Ratio SWR (optional)
Once the antenna has been tuned or the local conditions have changed, the question arises: How
well are the Reader and antennas matched?
A useful tool for assessing the matching of the antenna to the impedance of 50
Ω
is the SWR
meter. This device measures the ratio between incoming and reflected energy. A SWR value of up
to 1.3:1 is considered a good value.
The cable between the Reader and SWR meter should be either very short (< 20cm) or 7.20 m
(RG58 =
λ
/2) long.
After checking the SWR the SWR meter and the 18cm connection length between the SWR meter
and the T fitting on the Reader are removed.
