User's Manual

OBID
®
classic-pro Installation ID CPR.M02
Page 34 of 39 FEIG ELECTRONIC GmbH
E N G L I S H
8.4.2. Retuning the internal antenna: Trim capacitor C315
The antenna of the ID CPR.M02 can be detuned as a result of various ambient conditions 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
C405
Trim capacitor C405:
DO NOT CHANGE !!!
Trim capacitor C315:
Retuning the
internal antenna
X3
X4
X1
J1
V2
V1
C315
ID CPR.M02
Mit C315 Signalamplitude auf
Maximum drehen
V1 V2
X1
C65
Turn C315 to set am-
plitude to maximum