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Speeder X1 and X2 Configuration and API Guide
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[Count (10 minutes):
142]
CNT2
Option (prm50bit3): Vehicle count for the past ten minutes.
Value is updated once in a minute.
[Cars per hour: 852]
Flow
Option (prm50bit3): Traffic flow for one hour, based on the count
for the past ten minutes. Value is updated once in a minute.
[Average speed:
100]
AveSPD
Option (prm50bit3): Average speed for the past ten minutes.
Value is updated once in a minute.
Error response is the following; it is given instead of the speed reading: Speed = NA
4.1.1 Speed calculation method
The Speeder X1 is equipped with an advanced dual laser transmitter to allow
measurement of two consecutive distance profiles. Both lasers measure the profile from
the point where the beam hits onto the vehicle. The measurement starts, when the vehicle
arrives into the triggering window of the sensor. Laser which is responsible for detection
is selected with the traffic direction bit (parameter 2 bit 5). For approaching vehicles Beam
A detects vehicle and for departing Beam B respectively. The sensor starts the speed
measurement having detected the vehicle and checked the correctness of the triggering.
The principle of operation is to measure two distance profiles onto a vehicle from two
successive positions on the road. Both profiles include about 50 to 200 measurements
depending on the setup and speed of the vehicle. Both profiles are then analyzed and
converted to speed. Finally the profiles are compared to each other to get rid of the
errors and the final speed value is calculated.
This enhanced analysis results high accuracy speed values. The measurement onto a
vehicle may get result from any part of a vehicle and either from approaching or departing
vehicle.
4.1.2 Delayed trigger in speed measurement
Parameter 46 (Speed verification distance) sets the distance where speed based trigger
will occur. This distance can be set from 0.1 to 25.5 meters (parameter value in 0.1
meters, range 0-255). With this parameter it is possible to check whether or not the speed
reading provided by Speeder X1 is acceptable. Speed reading evaluation is based on
visual inspection i.e. how well the speed based travel time matches to the fixed distance
set by the parameter. Another application is to move the triggering point closer in order
that LPR-camera obtains acceptable illumination (provided by flash).
Setting the distance to parameter 46 enables the delayed trigger at DIGIN/DIGOUT (pin
5, grey wire). Parameter 17 Trigger length is used to set delayed trigger length. Trigger
signal operates normally at DIGOUT (pin 6, pink wire). Furthermore, it is possible to
disable normal trigger and set delayed trigger output to the DIGOUT signal by setting
Parameter 51 bit 5 (Speed Verification Digital IO Control).
