loop detectors

Applikation loop detectors LOOP

Vehicles and metal objects can be safely identifi ed by a loop embedded in to the driveway, consisting of several coils of copper wire and an inductive loop analyzer of the LOOP-series. Modern technology involving a powerful microprocessor enable a loop analysis over a large induction-area of 20-2000uH. The LOOP-series has 1- and 2-channel variations with several possible settings for:

• changes in the loop frequency
• boost-function suppression of sensitivity)
• detection of direction
• impulse/continuous contact
• output functions
• limiting dwell time
• response delay
• drop-out delay

The flash code of the LED-indicators shows the actual loop frequency and any error diagnosis.

Loop installation

The individual cores should not shift against each other. The loop geometry must not be allowed to change. If possible, the installation should be kept away from any metal objects.

Number of coils in the loop

perimeter	number of coils
U = 2 - 5m	N = 5
U = 5 - 9m	N = 4
U = 9 - 17m	N = 3

The aspect ratio should be between 1:1 and 1:3.

The feed line should be twisted 25 times per meter.

Loop geometry

The loop-width should be equal to or slightly smaller than the widest vehicle passing over the loop.

In order to detect two-wheeled vehicles, the loop should be set up as a trapezium or a parallelogram.

With a two-channel loop-detector it is possible to activate direction detection. The distance between the loops should then be half the length of the vehicle.

When there is only limited room it is advisable to lay the loop in the form of a fi gure 8.