Installation Manual

OBID i-scan
®
Installation ID ISC.ANT310310-A
FEIG ELECTRONIC GmbH Page 11 of 22 M90401-1e-ID-B.doc
E N G L I S H
4.4 The influence of metal on the reading range
A magnetic field cannot penetrate metal or other magnetically conductive materials. The course of
the lines of electric flux and the inductivity of the antenna is changed and has therefore a consider-
able influence on the reading range. Furthermore, the field is weakened by the mutual inductance
response the eddy current within the metal.
The change of inductivity may often be compensated with the help of the (re-)tuning electronics.
Figure 6
illustrates the influence of a metal plate on the antenna with (upper line) and without re-
tuning (lower line).
Figure 6: Reading range* in dependence on the distance to metal
Read range of a typical transponder, size 46 x 75 mm
2
, over the centre of the antenna, parallel
orientation to the antenna.
If metal parts cannot be avoided close to the antenna, please observe the following:
• The minimum distance between metal and antenna is 5 cm. A distance up to 30 cm will lead to
a considerable reduction in the reading range. At a distance of 50 cm to metal parts, there will
be almost no influence to be measured.
• Metal parts must not form closed loops or electric circuits. These have to be electrically sepa-
rated at one point.
• Metal parts in close vicinity to the antenna have to be grounded in star configuration with a
good HF-connection.