A common requirement for car parks is to monitor how many vehicles are in the car park and to display a ‘Full’ message when there is no parking space available and a ‘Space’ message when space is available. In a single level car park with up to four entrance lanes and four exit lanes, this can be provided by using a single counter module with increment inputs from equipment at each of the exit lanes and decrement inputs from equipment at each of the entry lanes. A single Space/Full sign can be installed at the entrance or several signs can be installed as appropriate if the entrance lanes are far apart.

The count is initially set to the total number of parking bays. The sign displays ‘Space’ and the entry barrier is enabled. As each vehicle enters, the value is reduced by 1 (decremented). As each vehicle exits, the value is increased by 1 (incremented). When the car park is full, the count value will be zero (the number of vehicles currently inside the car park is equal to the total number of parking bays). The counting module instructs the sign to display ‘Full’ and disables the entrance barrier (or entry control). Once vehicles leave, the count of free spaces rises above zero, the sign will change back to ‘Space’ and the entrance barrier will be enabled once again.

If there are no means of providing the increment and decrement inputs from the barrier control or access control equipment (where fitted) then this can be handled by loop detectors connected to road loops buried under the entrance and exit lanes. We recommend the use of dual-channel loop detectors linked to 2 loops in each lane. ‘A-B’ logic should be enabled (a feature of Nortech’s dual-channel loop detector). This allows the direction of the vehicles to be determined, thereby avoiding miscounts due to drivers reversing out of an entrance after being detected as entering the car park, or by drivers entering via an exit lane or leaving via an entry lane.

Nortech’s NCT200 counter module can accommodate up to 4 increment and 4 decrement inputs and has a counting range from –32500 to +32500.

Return to Application