Feig Electronic VEK S4 - Output Signal Assignments; Multiplexing and Synchronization

Manual VEK S4
6 03/09 FEIG ELECTRONIC GmbH
1.3.4 Tailgating
If a vehicle is driving to close to the car in front a dummy vehicle (Other, l = 4.5 m, v= last vehicle) is reported
with the vehicle speed of the car in front.
Note: A correct detection of driving direction is not guaranteed for all tailgating situations.
1.4 Possible outputs
Two Open Drain outputs each are assigned to every classification module. One of the functions listed below
can also be assigned to each output:
- no function (output deactivated)
- presence of a vehicle on the loops
- direction pulse signal
- pulse for vehicle crossing with vehicle class selection
- exceeding speed limit with vehicle class selection
- speed limit compliance with vehicle class selection
The function setting is made via the serial port using PC / Laptop with service program or host computer.
1.5 Multiplexing methods
The connected induction loops are switched on and off in rapid sequence, so that current flows only through
one loop at a time. This prevents mutual interference between the loops of a detector. All loops connected to
a detector can thus operate at the same loop frequency.
Kls-
modul 2
Kls-
modul 1
VEK S4
Time window 1
1 2 3 4
Inductance loo
p
s at a detector
1
2
3 4
1 2 3 4
1 2 3 4
Time window 2
T
ime window 3
Time window 4
1.6 Synchronisation
To prevent mutual interference between induction loops of multiple detectors, the latter can be synchronized
with each other using a connection in the front-side ribbon cable. All detectors connected via the
synchronous line process the multiplexing sequence synchronously. Only loops which are active in the same
time window can affect each other. Assigning the loops to the time windows is done by setting the multiplex
sequence.
Note:
• Adjacent loops should be assigned to different time windows.
• Loops in the same time window should be located physically as far away from each other as possible.