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Commissioning
English, Revision 02, Date: 12.07.2011
12
When crossing a transponder the sum voltage rises. After exceeding the
Threshold
for Decoding
the bit
TRANS_IN_FIELD
is set. After 4 x 8 ms ( = four data points)
is transponder code is decoded. The duration depends on the settings made under
Number of Equal Codes
in the submenu
Time & Code
. In this example
2
is cho-
sen, that means that the input code is compared with the two precedent codes.
After crossing the center of the antenna the
POSI pulse
is triggered. Its duration is
terminable. The bits
TRANS_IN_FIELD
and
CODE_OK
are deleted, as soon as the sum
voltage falls below the
Threshold for Decoding
. In this example a reserve from
6 x 8 ms for triggering the
POSI-Puls
is left. The crossing velocity is approx. 0.87 m/
s (140 mm length of antenna / 20 x 8 ms).
In the following protocols the impacts of a high interference level can be seen.
Figure 8
Diagram: commissioning protocol / high interference; sum voltage over
track
The interference level reaches up to 300 samples. At transponder 207 the noise is due
to a charging station so high, that it even influences the transponder signal. As an im-
pact it takes 9 x 8 ms until the transponder 203 is decoded (see Figure 9 on page 13).
This is sufficient for a slow crossing velocity of 0.5 m/s (140 mm / 33 x 8 ms) to gener-
ate a
POSI pulse
, in contrast a velocity of 1 m/s is to high, this transponder cannot
be crossed with such a velocity.
High interferece level