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Application-Note
ID ISC.ANT800/600
FEIG ELECTRONIC GmbH
Page 9 of 33
N11000-2e-ID-B.doc
If metal cannot be avoided in the vicinity of the antennas, note the following:
•
The minimum separation between metal and the antenna must be 10 cm (3.9 in). At 30 cm (12
in), the read distance will be significantly reduced. At more than 50 cm (20 in) there is virtually
no measurable effect.
•
The effect of metal parts depends greatly on their size and shape. Thin metal rods affect the
magnetic field lines less than objects having large surface area.
•
Larger metal surfaces (edge length > 50 mm) parallel to the antennas or the labels result in a
short circuit of the magnetic field lines. The result is that the label cannot be read.
•
Metal parts beneath the conveyor belt change the path of the magnetic field lines. This results
in significant loss of reading range. Horizontally oriented labels cannot then be read.
•
The metal parts are not permitted to form closed loops or circuits. Loops must be isolated at
some point around their perimeter to prevent formation of a closed loop.
•
The metal parts in the immediate vicinity of the antenna must be grounded in star fashion using
a good High Frequency connection.
•
Since the Reader is contained in a metal housing and the antennas are coupled into the cable
connected to the Reader, the Reader should be located at least 50 cm (20 in) from the anten-
nas.
•
The Reader housing should not be permitted to make any electrical connection with any metal
parts located near the antenna.
