General notes
The loop is the sensitive element of an alternated current, high frequency circuit, generated by a device (detector type LAB 90H) which creates a magnetic field. A distur-
bance is caused by a metal mass crossing the field; the disturbance is detected by the detector which causes the relay triggering.
Preparation of the loop
The magnetic loop, to be laid underground, is suited to detect metal mass and should be created by using an insulated, braided, continuous copper cable with 1.5 sqmm
minimum cross section.
The cable used should be at least 20 metre long (up to 40 metres maximum), irrespective of the perimeter developed by the loop.
Hence, as a general rule, the magnetic loops featuring a perimeter longer than 10 metres, should be made of two rounds of wire.
Loops having a perimeter less than 10 metres, but longer than 6 metres, should be made of three rounds of wire. Loops with a perimeter shorter than 6 metres should
have four rounds of wire.
The loop end (tail) should be braided up to the end to be connected to the detector. The tail length should be as short as possible.
Installation of the loop
Except in special cases, the magnetic loop should have a rectangular shape and should be normally laid with the longer sides perpendicular with respect to the traffic
direction. The ideal dimension of the loop is 2x1 metres.
The loop should be laid underground, in a hollow 10÷15 mm large and approx. 30÷50 mm deep. Dimensions and shape of the loop are shown in the drawing hereunder
(see Fig. 1).
Once laid underground, the loop should be protected and fixed with epossidic resin, cement or asphalt applied by melting inside the hole. If hot asphalt is used, make
sure that high temperature does not damage the cable. Connection of the loop to the point where the detector is installed must be underground, by means of the braided
tail. The tail should be as short as possible, and in any case, should not exceed 10 metres (standard tail: 5 metres long) in order to avoid a reduced detection sensitivity
and possible interference.
Braiding of the two ends should be not lower that 5 windings every 10 centimetres.
As regards installation, connection and calibration of the detector, follow instructions shown in the technical literature relevant to the device in use.
Note : in the event of adjacent loops, it is recommended to alternate three-winding loops with four-winding loops.
Interference
When two loops run one beside the other, the adjacent magnetic fields may cause mutual interference.
To avert this inconvenience, proceed as follows :
a) Modify the operating frequency. The nearer the loops, the greater the difference between frequencies.
b) Wherever possible, keep a distance of about 2 metres between near loops.
c) Shield all power cables which run near the loop conductors.
Minimum possible
(5 metre standard)
Braided tail
(5 braids every 10cm).
Single-cord wire, with 1.5 sqmm cross section (for the
number of windings see installation instructions)
• The unit should be used only for the uses intended by the Manufacturer.
• The user's instruction manual should be always kept available and handed out to every customer.
• Non authorized modifications, or the use of spare parts and additional equipment, which are not recommended or sold by the Manufacturer, can cause burning, electric
shocks and damage. The Manufacturer shall not be deemed responsible for improper use of the item and therefore no warranty will be granted.
• The equipment is covered by the warranty conditions granted by the Manufacturer, which are valid since the purchase of the equipment. The Manufacturer shall not be
deemed responsible for any parameter setting carried out by hand in an improper or incorrect way, as well as for any improper use of the equipment.
• Repairs shall be carried out by the Manufacturer only.
• Connections, start-up, servicing, measurement and adjustment operations on the detector should be carried out by specialized electricians, also qualified as regards
safety.
• When electrically powered equipment is used, the VDE regulations in force should be complied with, especially, although not in whole, the following regulations : VDE
0100, VDE 0550/0551, VDE 0700, VDE 07111, VDE 0860, VDE 0105 as well as safety and fire prevention regulations according to VBG4.
• When the display is off, this does not mean that the unit is not connected to the mains and is not powered.
• All operations to be performed on the unit and the relevant assembly should be carried out according to domestic standards regarding electrical equipment as well as
local directives.
• The user is responsible for the correct assembly and connection of the unit in compliance with the technical standards of the relevant country and according to all other
regional regulations in force. It is therefore recommended to take care of the following : dimension of cables, safety devices, earth, switching-off, cutting-off, monitoring
of insulation, safeguard against overload.
• The insulation of the connection cables to the 11-pole loop should be suited to 230V. The round loop corresponds to the basic insulation for 230V, according to VDE
0160 standard.
• The insertion and removal of the diagnostics cable on the special unit VEKFG2 as well as of the closure cap of the bush should be carried out with detector not powered.
At end of operation, reassemble the cover plate without which operation of the unit is not enabled.
4
1. Installation instructions (Fig. 1)
Direction of traffic
Fig.1
2. Safety and emergency instructions
2m