地感线圈的工作原理（The working principle of induction coil）

地感线圈的工作原理（The working principle of induction coil） 地感线圈的工作原理(The working principle of induction coil) HRB is a two channel intelligent loop sensor that should be used to detect vehicles, bicycles and other metal objects, suitable for parking lots, road vehicles Toll stations, signal lights, control systems, etc.. HRB uses the most advanced microprocessor technology, can meet all kinds of use ring Applications under the environment. As the metal passes through a coil buried under the road, the metal conductor changes the inductance of the coil, HRB Loop sensors detect metal by detecting variations in the inductance of the coil. * technical parameters Functional parameter Fully automatic tuning The coil inductance range is 50-1000 H Nine level sensitivity optional Two operating frequencies Automatic sensitivity Relay output mode The relay pulse output width is 300 ms The reaction time is 100 ms Environmental drift compensation Indicator light Output relay 1A/30VDC Front panel reset button Surge current protection The power supply is AC220V + 10% Environment parameter Storage temperature -40oC to +85oC The operating temperature is -40oC to +65oC The maximum relative humidity is 95% Mechanical parameter Shell: PC+ABS engineering plastics Mounting: DIN Guide Size: 110 (L) X60 (W) * 100 (H) (mm) Working principle The HRB loop sensor detects metal objects by detecting variations in inductance of metal objects in the induction coil. The coil is wound by a multi turn wire, buried under the road and filled with cement. The coil lead is connected to the HRB. As the metal passes through the induction coil, the inductance of the wire coil varies. This change is detected by the HRB, through the internal intelligent controller operation to determine the metal, and through the output relay output signal. Because of the intelligent control of the microprocessor, the sensitivity of the HRB can be adapted to various requirements, and the induction coils and lead wires of different sizes can also be well matched. Coil tuning: the tuning process of the HRB is fully automated. When the HRB is powered on or reset, it will automatically tune to the coil it is in, with a tuning range of 50 to 1000 milli. This wide tuning range ensures very low requirements for the coils and leads. Once the tuning is good, any environment in which the inductance changes slowly will be fed back to the detector inside the compensation circuit to ensure normal operation. Sensitivity: the sensitivity of the HRB depends on a number of factors, such as coil size, coil turns, lead length, and whether there is metal below the loop. The sensitivity of the HRB should be determined in terms of specific applications. The sensitivity of the HRB is particularly optimized for parking management systems. When selecting lower sensitivity, smaller objects, such as bicycles and trolleys, do not cause detector movements, and are better suited for vehicles with higher chassis and vehicles with trailers. Reaction time: the reaction time of HRB is defined as the time interval from the metal into the induction coil to the HRB to give the indication signal. The reaction time of the HRB detector is specially optimized for the parking management system, typically 100 milliseconds. The short reaction time is prone to malfunction in the presence of electromagnetic interference, Too long reaction time can also cause inconvenience. Installation guide Whether the HRB works well depends to a great extent on the induction coil it is connected to. Several important parameters of the coil include: loop material, coil shape, and correct construction. When installing, you must pay attention to the following. The HRB must be installed in a watertight environment as close to the detection coil as possible. Coil string winding: when the two induction coils are very close, the magnetic fields of the two coils are superposed together, causing interference with each other. This phenomenon is crosstalk. Crosstalk results in erroneous detection results and HRB deadlocks. The elimination of crosstalk in coils adjacent to but belonging to different sensors can be achieved by the following measures: We choose different working frequencies. The closer the two coils are, the greater their frequency of work should be; We will increase the spacing between adjacent coils. The spacing between the detecting coils must be greater than 2 meters; "Good shielding of the coil lead wire. The shielding wire must be at the end of the detector, the ground coil, the cable and the connector: coil, cable and connector shall be preferably made of copper wires. There should be no wiring between cables and fittings. If the wiring must be secured, make sure the connection is reliable. Weld them together with a soldering iron and place it in a waterproof position. The wire diameter shall be no less than 1.5 mm2. Double layer waterproof wire is best. Coil shape: the probe coil shall be rectangular unless conditions permit. Two long sides perpendicular to the direction of movement of the metal, The distance between each other is recommended to be 1 meters. The length of the long side is determined by the width of the road, usually 0.3 meters narrower than the road. If the coil is longer than 10 meters, it needs to be wound around two turns. If the circumference is within 10 meters, you need to circle three turns or more. The circumference is within 6 meters, to circle four turns. A good way to install is to replace the adjacent coil with three turns and four turns. Coil installation Essentials: first to use Qielu coil laying machine in the road cut a groove. Chamfer 40 degrees on four corners to prevent sharp corners from damaging the coil cable. Groove width is usually 4 mm, depth 30 to 50 mm. At the same time, when laying cables, leave enough length to connect to the HRB, and make sure there is no connection in the center. After winding the cable, the cable is drawn out through the lead out slot. Output lead is closely twisted form, at least 1 meters for 20 weeks. The maximum length of the lead shall not exceed 100 meters. Because the sensitivity of the probe coil decreases with the increase of the lead length, the length of the lead cable should be as short as possible. When the coil is buried, seal it with cement or asphalt. 2, work frequency setting The coil frequency adjustment is carried out with two DIP switches arranged on the circuit board, such as adjusting the panel It must be opened (loosen the four locking screw lamp). The two channels can be set with different frequencies. OFF position: means high frequency operation ON position: means low frequency operation; Switch 2 is used for channel A, switch 1 is used for channel B. When two adjacent coils interfere with each other, frequency switching is necessary, one detector can be set to "ON", and the other "OFF"", So that the frequencies of the adjacent two coils are different. When only one coil is used, there is no need for frequency adjustment. After any change in the position of the frequency switch, reset operation is performed by pressing the reset switch. 1, sensitivity adjustment The HRB-2 loop sensor detection sensitivity of each channel is divided into 9 levels, can be set by the two knobs on the front panel, "9" as the most advanced, the lowest level for the "1", "0" as for line frequency measurement is not used for sensitivity adjustment (see table two). Table two sensitivity table 4. Reset switch When the HRB is powered on, it automatically adjusts to the attached coil. When changing the frequency switch on the HRB Set, or change the position or shape of the coil, must be tuned from the new. Press the reset switch to tune from the new. 5, work mode setting The HRB panel has 3 dials for changing the operation of the pulse relays (A2 and B2), with the codes of 1, 2, and 3 respectively. HRB each channel has two relay outputs, respectively A1, B1 and A2, B2. The A1 and B1 are standard outputs. When the vehicle or metal body is on the coil, the A1 or B1 relay moves, the vehicle or metal body leaves the coil, and the A1 or B1 relay resets. A2 and B2 is a multifunctional pulse action relay, they can be used as a pulse relay or as an additional vehicle in place of the two relay relay, respectively, can be used for vehicle detection in parallel direction, three DIP front panel switch is used to adjust the various modes of operation, the key number is 1, 2, 3. To vehicle detection, for example, A2 and B2 in the following ways: 6 、 debug specification We will choose the lowest sensitivity to ("1"); We set the pulse relay A2 and B2 mode; The metal induction coil on the move; The power supply is switched on, the inductor loop tuning, LED indicator of each loop indicating the state of circuit, LED flashes, LED goes out after a good tune. The loop sensor will conduct coil testing during the tuning process. When the inductance of the coil exceeds the permissible range or the circuit breaks or short-circuit occurs, the corresponding channel LED will continuously flash