Loop Detection Coil With Fast Response Vehicle Loop Detector Coil
Loop Detection Coil
Loop Detection coil. When making the coil, leave enough length of wire to connect to the loop sensor and ensure there is no joint in the middle. After winding the coil cable, the cable must be made into a tightly twisted pair, requiring at least 1 meter to be twisted 20 times. Otherwise, the untwisted output leads will introduce interference that makes the coil inductance value unstable. The output lead length should generally not exceed 5 meters. Since the sensitivity of the detection coil decreases as the length of the lead increases. So the length of the lead cable is as short as possible. The loop detection coil, the coil lead feeder, and the capacitance of the vehicle detector constitute an LC oscillating circuit. The ground sense coil detector detects the oscillation frequency of the LC oscillation circuit. If the oscillation frequency changes with respect to the reference frequency, the ground detector determines that there is a vehicle passing, so ensuring that the change of the oscillation frequency is only the key to the success of the detection of the ground detector is related to the entry of the vehicle into the coil.
The vehicle loop detection coil should be rectangular unless conditions do not allow it. The two long sides are perpendicular to the direction of movement of the vehicle (metal), and the spacing between them is recommended to be 1 meter. The length of the long side depends on the width of the road and is usually 0.5 m narrower than the width of the road. The number of turns of the coil is 4 or 6 turns. If two coils are adjacent, one 4 turns, one 6 turns when the cable is buried, leaving enough length to connect to the loop sensor and ensure that there is no joint in the middle. After winding the good quality loop detector coil cable, take the cable out through the lead-out slot. The output leads are in the form of tight twists, twisted 20 times at least 1 meter. The maximum length of the lead should not exceed 10 meters. Since the sensitivity of the detection coil decreases as the length of the lead increases, the length of the lead cable should be as short as possible. After the coil is buried, it is sealed with cement or asphalt.
The loop detection coil is buried first by cutting the groove on the road surface with a road cutter. Perform a 45-degree chamfer on the four corners to prevent the corners from damaging the coil cable. The grooving width is generally 4 to 8 mm and the depth is 30 to 50 mm. Also cut a coil to the side of the coil for the coil lead. However, it should be noted that water or other liquids must be infiltrated in the groove. The ground coil must be straightened when winding the ground coil, but do not stretch too tightly and close to the bottom of the groove. After the coil is wound, the twisted output lead is led out through the lead-out slot.