心静电磁

induction coilThe principle is as follows:

1. working principle

The ground induction coil vehicle detector is a vehicle detector based on the principle of electromagnetic induction. Usually, a ring coil is buried under the roadbed of the same lane to provide a certain working current as a sensor. When the vehicle passes or stops on the coil, the iron on the vehicle itself will change the magnetic flux in the coil, causing the inductance of the coil circuit to change. The detector determines the state of the passing vehicle by detecting the change in inductance. There are generally two methods for detecting the change of inductance: one is to use a phase latch and a phase comparator to detect the phase change; the other is to use a coupling circuit composed of a loop coil to detect the oscillation frequency.

2. system composition

The ground induction vehicle detector includes a ground induction coil and a detector. The coil is used for data acquisition. The detector is used to realize data judgment and output corresponding logic signals. The detector is generally composed of a rack, CPU, detection card and wiring terminals.

The CPU is a module for calculating the collected signal. It is generally a single-board computer with an embedded operating system, with powerful digital computing, storage capabilities and communication interfaces. By scanning the port, capture the change time of the level, so as to calculate the corresponding traffic data

When the detection vehicle passes or is stationary in the detection area of the induction coil, the inductance through the induction coil will decrease. The function of the detection card is to detect this change and accurately output the corresponding level. When detecting a vehicle passing at a high speed, the detection of the vehicle length and the vehicle speed may not be accurate, and the sensitivity of the detector needs to be adjusted correctly. At present, the vehicle detector generally has a multi-level sensitivity adjustment function.

The Role of 3. Grounding Induction Coil in Parking Lot System

In the parking lot system, to determine the role of the grounding induction coil, you first need to know the installation location of the grounding induction coil. The grounding induction coil is generally installed in the following four positions:

1. Entrance ballot box (entrance controller);

2. One at the entrance and exit gates;

3. Export ticket box (export control machine);

The grounded induction coils used in the industry are generally copper core wires. People who have attended junior high school should know that when a metal object passes through a coil, it generates an electric current. This principle is used in the parking system;

That's why we call it a coil. The manufacturing method of the coil is relatively simple, that is, a certain length of copper wire is wound several times. This explanation is familiar to everyone,;

The ground sensing effect at the 4. inlet controller can be in two ways:

1. Loss prevention card

As we all know, in the standard one-in-one-out system, temporary vehicles enter the scene through automatic card retrieval. He just had to push a button. At this time, the role of ground sensing is to pick up the card when there is a vehicle, instead of letting people stand up and press the button

2. Ground pressure sensor card reader

In the remote card reading system (Bluetooth system, license plate recognition system), the local ground induction is used to identify the direction of the vehicle;

The role of 5. entrance also has two aspects

1. Anti-smashing car. When there is a feeling that the car is on the ground, the road door rod will not fall off;

2. Rollover bar

The ground induction at the outlet control machine is similar to the ground induction of the inlet controller. In the remote card reading system (Bluetooth system, license plate recognition system), the ground induction is used to identify the direction of the vehicle.