REALISATION OF THE SENSITIVE ELEMENT (FIG. 1)
The detectors are suitable for coils made up with an insulated copper wire with a cross-section of at least 1.5 sq.
mm. Preferably use twisted copper wires with at least 20 twists per metre to connect the detector to the coil.
Jointing in the coil wires and in the twisted cable is not recommended. If the wires used for the twisted cable are
especially long or in proximity to other power cables, shielding of said wires is recommended. Earthing of the shield
should only be made at the extremity of the detector.
Excepting special cases, the detection coils should be rectangular. Install with the longer sides placed at right angles in
the direction of vehicle movement. These sides should ideally be kept at a meter one from the other. Coil length is a
function of the width of the road surface to be monitored. A distance of no more than 300 mm is recommended between
the coil and each edge of the road surface. For coils running over a perimeter of more than ten metres two wire windings
are normally employed, while for coils with a lower perimeter three or more windings are required, and four windings are
required for coils with a perimeter below six metres.
All permanent coil components must be secured to the road surface in appropriate grooves made using masonry
cutting tools or the like. A cross-cut at a 45° inclination must be made at the circuit angles so as to prevent the risk of the
coil cable being damaged in proximity to the apex of the right angles.
Nominal groove length: 4 mm.
Nominal groove depth: 50 mm.
The coil-detector connection cable must also be laid in an appropriate groove running from one of the circuit angles
along the circuit perimeter to the road surface edge. To ensure wiring continuity between the coil and connection cable
allow for a long enough lead to reach as far as the detector before inserting the cable inside the coil groove. After laying
the required number of wire windings in the groove along the coil perimeter, route the wire towards the road edge
through the connection cable groove.
It is advisable that connection cable length not exceed 100 metres. As coil sensitivity diminishes proportionally to
connection cable length the latter should be kept as short as possible.
Coils are secured to road surface by means of a quick-drying compound containing epoxy resin or asphalt mastic
applied hot.
2
1.5 mm section cable
Cable width
Groove
depth
Fig. 1
0,3 m
max. 1 m
max. 5 m
0,3 m
At least 3 turns are recommended
At least 20 twists per metre
Note
:
It is advisable to use an only piece of uninterrupted cable to forme the loop. Therefore, it is preferable to make a
preliminary of the cable length.
Ex. (Perimeter loop per twists) + distance of the 200 mm.
15 mm
25
mm
Sistemi Elettronici
di Apertura Porte e Cancelli
International registered trademark n. 804888
®
67411510
Rev.01 - 05/2013
11
English
