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Identification Systems
HG 71450-A
English, Revision 02, Date: 20.01.2015 8
1.3.3 Signals and Timing
Figure 5
Signals and Timing
Initially the data is insecure and the signal strength is still small (area II). Approaching
further the signal becomes stronger and can be read completely. Finally the core recp-
tion range area I is reached. The exit from the reception range is detected as soon as
the thresholds 3 and 4 drop.
Crossing the field border at point 4 releases the center signal. Passing the next detec-
tion ranges (5 to 8) the data is read again and output. Following this at the field border,
point 8, no center signal will be generated. The center signal will also not be generated
if the vehicle passes points 1 to 4 and then stops in the data-free range. The position-
ing signal for this transponder will only be sent again if another transponder with a new
code is read or a reset is carried out via the commando, see 2.2.7 on page 13.
NOTE! If a vehicle stops before the positioning pulse ends and changes
the direction of travel, a wrong positioning pulse is generated on
position 1 or 4. These positions can not be defined exactly.
Thus
the identification system should only be used in installations
without any change in the direction of travel.
NOTE! Interfering signals in the areas between point 2 and 3 (or 6 and 7)
can lead to data errors. In this case positioning pulses are gener-
ated at the corresponding,
wrong position.
Reading antenna underneath
Transponder Reception ranges
Area I
Area II
Direction of travel
Antenna length
Data-free range (reception gap)
Midpoint
Crossover
(Positioning pulse)
Data
Security
Serial Data
NF
Signals
and Timing
(not to scale)
Z
t
= Positioning pulse time (Duration of the midpoint crossover pulse) = 100 ms
Z
t
the vehicle