Operating Manual HG G-98830YA | English, Revision 02 | Date: 21.06.2021
79
Troubleshooting – Chapter 14
14.2 Reducing Interferences
14.2.1 Which Interfering Influences are There?
If the values measured with the antenna are unreliable and/or inaccurate, the follow
-
ing interferences may be the reason, for example:
Metallic objects
Electrical loops
Interference frequencies in the range of 64 ±4 kHz
Interference voltages due to current-carrying lines laid too close together
(exception: supply line of the antenna itself).
Transmission of interference via the metallic floor of a vehicle.
To detect such interference and either eliminate it or reduce its influence, proceed
as follows:
Always try to avoid external interference first by observing the operating
conditions specified in this manual.
Only then re-adjust the positioning thresholds.
The adjustable thresholds are defined in sections 10.2.6 „(T)ime & Code“ on page 56
and 10.2.7 „(F)requency & Antenna Tuning“ on page 60.
In order to tune the antenna so that it reads the transponders correctly, but is not af
-
fected by interference on the entire driving course as far as possible, we recommend
adjusting the following values:
Level to Noise Error
Threshold for Decoding
Level for Positioning/Calculation
14.2.2 What happens when Crossing a Transponder?
To illustrate the meaning of the individual threshold values and their correct setting,
the process during a transponder crossing is described below.
Every 2 ms a check is made whether the reference voltage exceeds the limit
Threshold for Decoding
.
If that is the case, the Bit
TRANS_IN_FIELD
is set and the
NOISE
counter is
incremented.
An attempt is made to read a code every 8 ms.
If the code was read successfully, the
NOISE
counter is reset and then the sum
of codes defined in
Number of equal Codes
is compared.
If this test was successful, the
CODE_OK
bit is set.
NOTICE
Changes of the antenna parameters can detune the antenna!
The following modifications to the antenna parameters can detune the antenna
to such an extent that a normal function is no longer possible.
Save the transponder antenna configuration before each change so that you
can restore it if necessary (see 10.2.16 „(1) Import / (2) Export User
Parameter“ on page 72).
