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Speeder X1 and X2 Configuration and API Guide
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The software calculates two consecutive speed values. First it calculates quickly a rough
speed value utilizing preliminary results of the collected data. This value is called
‘QSpeed’. QSpeed is used to generate triggering output for speeding vehicles in real time.
Speeder X1 detects the driving direction of the vehicle and compares it to the setting
(prm2bit5). In case driving direction is opposite speed value cannot be calculated and
QSpeed value is set as wrong direction “QSpeed = WD”.
Thereafter the sensor calculates the speed value with a more sophisticated algorithm
utilizing
all the collected data. The calculation may take 50…150 ms depending on the
quantity of data.
Typically vehicles that are changing lanes or driving on the side of the lane cause the
biggest errors, because the sensor may measure the speed from the side of the vehicle
or the measurement point may change significantly during measurement. In the cases of
difficult data or poor aiming, the sensor typically indicates “Speed = NA”.
The result given by the sensor is as follows:
(CSV, control byte 4 bit 6 is set):
caption
;DIST_A;DIST_B;ELT;DIR;QSPD;SPD;Q;Size;OCC;Height;INT;CNT;ERR;
A_OK;A_ALL;B_OK;B_ALL;CNT2;Flow;AveSPD
results
<;3655;3328;0:00:02.774;A;106;103.2;01;003;0127;123;02.497;0000002;000;
163;165;133;133;142;852;100;>
Result fields are described in the table below. In error situation speed value is zero.
(CSV not set):
Sensor
CSV
Explanation
T 3655 3328
DIST_A
DIST_B
Vehicle was detected by beam A at 36.55 metres (B 33.28)
[ELT: 0:00:02.774]
ELT
Option (prm50bit0): Time from the beginning of the
measurement session
[INT: 02.497 s]
INT
Option (prm50bit1): Time between triggers
[CNT: 000002]
CNT
Option (prm50bit3): Number of the triggering
[A: 163/165
B: 133/133]
A_OK/ALL
B_OK/ALL
Option (prm51bit4): Amount of measurement results from beam
(A/B) and accepted results for speed calculation. This output is
intended for R&D phase evaluation.
QSpeed = +106
QSPD
Calculated quick speed value [km/h]
[Height = 123]
Height
Option (prm26bit7): Height value is the difference between the
shortest detected distance to the vehicle and triggering window
maximum.
[discard = 0]
ERR
Option (prm51bit4): When nonzero discard value is received the
speed value is not fully reliable. This output is intended for R&D
phase evaluation.
Speed = +103.2
km/h (1)
SPD
Result of a more sophisticated calculation. Value in parenthesis
is an estimate for the error direction and magnitude.
(‘-‘ Means
possibility for lower reading than the real value).
[Size = 3]
Size
Option (prm2bit7): Size value that is based on the speed and
time the vehicle stayed
in the sensor’s field of view.
[OCC: 127 ms]
OCC
Option (prm50bit2): Time how long the vehicle has been in
Triggering window
