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Copyright 2004 by Siemens AG
J31069-D0158-U001-A0-7618
If metal parts in the vicinity of the antenna cannot be avoided, note the follo-
wing:
SA minimum distance of 100 mm should be maintained between the antenna and
metal parts in all directions. At 50 mm and beyond, the read range will be
greatly impaired. At distances to metal of 150 mm and beyond, there are on
measurable losses.
SThe degree to which metal parts will have an effect is greatly dependent on
their size and shape. Thin metal poles have less influence on magnetic field
lines than do large surfaces.
SLarge metal surfaces (edge lengths > 50 mm) that are parallel to the antennas
or labels will cause the magnetic field lines to short circuit. This will make it im-
possible to read the labels.
SAny metal parts beneath the conveyor will alter the path of the magnetic field
lines. This will greatly impair the read range. It will be impossible to read labels
with a horizontal orientation.
SMetal parts should not form closed loops or electrical circuits. If neces-
sary, they should be disconnected at a suitable location.
SAny metal parts in the immediate vicinity of the antenna must be grounded with
a good HF connection using a star ground circuit.
SBecause the read/write unit is installed in a metal housing and the antennas can
be coupled to the cables of the read/write unit, the unit should be mounted at
least 500 mm from the antennas.
1.4 Information on mounting and laying the antenna cables
To suppress interference, an EMC snap ferrite must be installed on each antenna
cable (including on the antenna cable between the SLG and the antenna duplexer).
The coaxial cable must be passed through the EMC core at last four times in tight-
fitting loops. The distance between the ring core and the connector to the read/
write unit or antenna duplexer should not exceed 100 mm.
The antenna cable should always be vertical when leading away from the anten-
nas. The cable should be laid at least 200 mm from the antennas.
There will otherwise be a loss in output.
All antenna cables must be laid at least 300 mm from parallel live cables.
Unused cable length must be wound into a coil of ∅ = 100 to 150 mm.
If the standard antenna cable is too short, it can be lengthened by 7.20 m using the
extension cable. This will lead to slight losses in range.
To achieve the best possible read ranges, the antenna cable should not be shorte-
ned or extended.