HS/FS Car passage detection and timing

[Warichet]

Hello,

I've installed a photocell (A) for car passage detection. It works fine.
Now I want to detect the car passage direction, so I've installed a second photocell (B, 15m away).

Is there any Baustein to know if A triggered before B or reverse ?

[vietgilles]

Hi,

for control the direction, 15 meter distance is to much. 1 meter is ok and better, so you can detect an car and not a person. I do this on park-house control.
For your problem, look for a special light sensor with two outputs for direction, the price is not so high, but is more save.

greetings
Martin

[Gaston]

Fo reliable direction detection the light barriers should be one next to the other far enough that both do not interfere and allow the Evaluation to take place before th esecond barrier is triggered and near enough that both trigger with the passage of the smallest object.

What comes me first into mind to realize this is the Siemens Logo module. I would think it is quick enough to evaluate this correctly but may require a model with fast inputs.

However I think it is not a good choice since to my understanding the sending of KNX object cannot be triggered but is triggered by a state change. So one would need to have 2 objects, one for th edirection and one for the "Validation", i.e. when both barriers are in triggred state.