User's Manual

OBID
®
classic-pro Installation ID CPR.M02/ANT19
FEIG ELECTRONIC GmbH Page 16 of 20 Manual-M21001-3de-ID-B.doc
3.4.2. Retuning the internal antenna (ID CPR.M02.VP/AB-C)
The antenna of the ID CPR.M02.VP/AB-C can be detuned as a result of various ambient condi-
tions such as nearby metal objects (see Section 8.5). This detuning can be compensated to some
degree using the trim capacitor C315.
Fig. 3.4.3-1: Trim capacitor for retuning the antenna
The integrated antenna can be retuned with the aid of an oscilloscope (bandwidth ≥ 20 MHz). To
do this, short the GND terminal of the oscilloscope probe with the probe point and hold it over the
circuit board of the ID CPR.M02. The probe then forms a measuring loop for the radiated magnetic
field of the ID CPR.M02. The distance between the oscilloscope probe and the ID CPR.M02 should
be between 0 and 3 cm.
Use the software command „RF-ON“ (0x6A) to turn on the HF field of the ID CPR.M02. A 13.56
MHz signal should be visible on the oscilloscope screen.
To tune the internal antenna, now set the signal amplitude of the 13.56 MHz signal to maximum
using trim capacitor C315.
Fig. 3.4.3-2: Configuration for tuning the internal antenna
X1
J1
V2V1
C315
X3
X4
C405
Trim capacitor C315:
Retuning the integrated
antenna
Trim capacitor C405:
DO NOT CHANGE !!!
ID CPR.M02
V1 V2
X1
C65
Turn C315 to set amplitude
to maximum