M8M12M18 Hall switch magnetic sensor switch 12-24V Hall proximity switches N pole S pole into ..

1 Basic profile edit this section Hall sensor Hall sensor Hall sensor is a magnetic field sensor based on the Hall effect produced. Hall effect is a magnetic effect, this phenomenon is Hall (AHHall, 1855-1938) in 1879 in the study of metal conductive bodies found. Later found semiconductors, conductive fluid, also have this effect, and Hall-effect semiconductor stronger than metal, using a variety of Hall elements made this phenomenon, widely used in industrial automation technology, detection technology and information processing aspect. Hall effect is the basic method of Semiconductor Materials. Hall effect experimentally determined by the Hall coefficient, can determine important parameters conductivity type semiconductor material, the carrier concentration and carrier mobility rate. 2 Main features editor of this paragraph (a) linear Hall sensor Hall sensor Hall sensor output characteristics of voltage and magnetic field intensity linear relationship shown in Figure 3, can be seen in the magnetic flux density range B1 ~ B2 are better linearity, is rendered in saturation magnetic flux density beyond this range. Characteristics (b) switching Hall sensor shown in Figure 4, which is the operating point BOP "open" magnetic induction, BRP is the release point "off" magnetic induction. Hall sensor Hall sensor when the applied magnetic flux density exceeds the operating point Bop, sensor output is low, when the operating point of the magnetic flux density falls Bop below the sensor output level unchanged, the release point has to be reduced to BRP, sensor only jump from low to high. Hysteresis of the switching action is more reliable between Bop and BRP. There is also a "key-lock type" (or "latch type") switch type Hall sensor, its characteristics as shown in Figure 5. Hall sensor Hall sensor when the operating point of the magnetic flux density exceeds Bop, the sensor output jump from high to low, and to withdraw after the external magnetic field, the output status remains unchanged (ie latched state), it must be applied to the anti- When the magnetic flux density to achieve BRP, to make level changes. 3 basic terms edit this section is divided into a linear Hall sensor Hall sensor Hall sensor and switch two kinds. (A) linear Hall sensor Hall element, linear amplifier and emitter follower composition, it outputs analog. (B) switching Hall sensor by the regulator, a Hall element, a differential amplifier, Schmitt trigger and output stage, which digital output. Hall sensors can also be divided into open-loop and closed-loop principle works. Open loop [1] is switching, closed-loop linear type is 3.1 Hall effect in semiconductor thin ends to control the current through I, and applied magnetic flux density in the vertical direction of the sheet to the uniform magnetic field B, then vertical in the direction of the current and the magnetic field, it will generate a potential difference of the Hall voltage UH 3.2 Theoretical basis Hall sensor Hall sensor is a Hall effect fluid theory foundation "MHD power generation," the. 1) Current sensor must RMS appropriate selection of different specifications of products according to the measured current rating. The measured current over a long time, can damage the pole end amplifier tube (referring to magnetic compensation), under normal circumstances, twice the overload current duration shall not exceed one minute. (2) the voltage sensor product description must be in the primary series with a current limiting resistor R1, so that the primary side to get the rated current, in general, twice the overvoltage durations less than 1 minute. (3) the best accuracy current and voltage sensors is in the primary side rated conditions, so when the measured current is higher than the rating of the current sensor, the sensor should be used in a correspondingly large; when the measured voltage is higher than the voltage sensor When rating, readjust the current limiting resistor. When the measured current is below the rated 1/2, in order to get the best accuracy, you can use multiple number of turns of the way. (4) Insulation withstand voltage 3KV sensor can long-term work 1KV and below 1.5KV and below the AC system and DC systems, 6KV sensor can long-term work in 2KV for ac systems and dc systems 2.5KV and below , be careful not to excess pressure. (5) requires the use of a device to obtain good dynamic characteristics, it is best to use a single copper and aluminum busbar and coincide with the aperture, and a large number of turns or on behalf of small, will affect the dynamics. (6) When using the Hall sensor Hall sensor large current DC system, for some reason the power supply or open circuit failure, the greater the core remanence, is noteworthy. Residual magnetism affect accuracy. Demagnetization method is to work without the power, through an alternating current in the primary side and gradually decreases its value. (7) the ability of the sensor against external magnetic field: a distance sensor 5 ~ 10cm sensor 2 times the value of the primary current exceeds the current, the resulting magnetic field can resist. Three-phase high-current wiring, phase distance should be greater than 5 ~ 10cm. (8) In order to make the sensor work in the best measurement of the state, should use simple typical power supply Figure 1-10 describes. Magnetic saturation point and circuit saturation point (9) of the sensor, it has a strong overload capacity, but there is a time limit of overload, overload during the test, more than twice the overload current must not exceed one minute. (10) the primary current bus temperature should not exceed 85 ℃, which is characteristic of ABS plastic decisions, users have special requirements, optional high-temperature plastic shell to do. Hall device has many advantages, their solid structure, small size, light weight, long life, easy installation, low power consumption, high frequency (up 1MHZ), shock-resistant, not afraid of dust, oil, moisture and salt spray, etc. contamination or corrosion. High precision linear Hall devices, good linearity; Hall switch device non-contact, no wear clear, the output waveform, jitter, no bounce, position repeatability and high accuracy (up to μm level). Wide operating temperature range of compensation and access to a variety of protective measures Hall device up to -55 ℃ ~ 150 ℃. According to Hall device features they can be divided into: Linear Hall and Hall switch devices. The former analog output, which outputs digital. According to the nature of the object to be detected may be their applications are divided into: direct and indirect use applications. The former is directly detected by detecting the magnetic properties of a magnetic field or the object itself, which is the magnetic field detecting human subjects' set, with the magnetic field to be detected as a carrier of information, by which, the number of non-electric, non-magnetic physical quantities such as force, torque, pressure, strain, position, displacement, velocity, acceleration, angle, angular velocity, number of revolutions, speed, and work status change time, into power to detect and control. 3.3 Hall element according to the Hall effect element using a semiconductor material, it is called the Hall element. It has sensitive to magnetic fields, simple structure, small volume Hall sensor Hall sensor, wide frequency response, large output voltage and long life, etc., and therefore, in the fields of measurement, automation, computer and information technology has been widely used. Common Hall element models are: Unipolar Hall YS44E, MH282, YS580, SS541. Bipolar Latch Hall YS8920, MH188,41F, EW512. Linear Hall HG302C, A1302, 49E, HG106C. 4 Other data editing application of this paragraph 4.1 Hall sensor (a) linear Hall sensors are used to measure physical quantities. For example: 1. Due to the current sensor Solenoid magnetic fields, the size proportional to the current in the conductor, it is possible to use a Hall sensor to measure the magnetic field in order to determine the size of the wire current. Using this principle can be designed into the Hall current sensors. The advantage is that no electrical contact with the circuit under test, does not affect the circuit under test, the measured power does not consume power, particularly suitable for large current sensing. Hall current sensor works shown in Figure 6, the standard ring core has a gap, a Hall sensor into the gap in the ring around the coil, generating a magnetic field when current flows through the coil, the Hall sensor signal output. 2. Displacement measurement shown in Figure 7, two permanent magnets of the same polarity relative placement, linear Hall sensor in the center, the magnetic flux density is zero, this point can be used as a zero displacement, when the Hall sensor in the Z axis when making △ Z displacement sensor has a voltage output proportional to the magnitude of the voltage magnitude of displacement. If the tension, pressure and other parameters into displacement, can measure the size of the tension and pressure, shown in Figure 8, the force sensor is made according to this principle. B) switching Hall sensors are used to measure the number of revolutions, speed, wind speed, velocity, proximity switches, closed inform, alarm, automatic control circuit. 1. Measuring speed or number of revolutions 9 ,, at the edge of a non-magnetic disk stick a magnet, a Hall sensor placed close to the edge of the disc, the disc rotation, the Hall sensor outputs a pulse, which can measure the number of revolutions (counter), if the access frequency meter, you can measure the speed. If the switch-type Hall sensor according to a predetermined location regularly arranged on the track, when mounted on a moving vehicle permanent magnet through it, you can measure the pulse signal from the measuring circuit. According to the distribution of the pulse signal can be measured velocity of the vehicle. 4.2 Notes (1) In order to get a better dynamic performance and sensitivity, we must pay attention to the coupling of the primary coil and the secondary coil, and to couple well, preferably with a single wire and wire Hall sensor module is completely filled aperture . (2) when the large DC current flows through the primary coil sensor and the secondary circuit has no power | voltage regulator or secondary side open, its magnetic circuit is magnetized to produce residual magnetism, affect the measurement accuracy ( it is first switched on and a measuring terminal M) when using this happens, the first demagnetization process. The method is without secondary side power circuit, and the size of the same level through a AC current in the primary coil and decreases its value. (3) In most cases, the Hall sensor has a strong resistance to external magnetic interference, usually 5-10cm distance module exists between a double-magnetic interference in the work of the current generated by current Ip is negligible when, but a stronger magnetic interference, to take appropriate measures to resolve. Conventional methods are: ① adjustment module direction, so that the impact of the external magnetic field on the module minimum; ② on the module plus cover an anti-magnetic metal shield; ③ selection of belt modules power supply repair 多霍尔 double Hall element or element; ( Best precision 4) measurement is obtained under rated, when the measured current is much lower than the rated, best accuracy, the primary can use multiple turns, namely: IpNp = rated ampere-turns. In addition, the primary feeder temperature should not exceed 80 ℃. Features Hall sensor (compared with conventional transformer) 1, Hall sensors can measure current and voltage arbitrary waveform, such as: DC, AC, pulse waveform, and even the measurement of transient peaks. Secondary current waveform faithfully reflects the primary current. Ordinary transformer is unable to its match, it is generally only suitable for measuring 50Hz sine wave. 2, between the primary circuit and the secondary circuit is completely electrically insulated, insulation voltage is generally 2KV to 12KV, 20KV special requirements of up to 50KV. 3, high precision: in the work area temperature accuracy of better than 1%, which is adapted to measure the accuracy of any waveform. Ordinary transformer general accuracy of 3-5% and for 50Hz sine wave. 4, good linearity: better than 0.1% in May, dynamic performance: response time less than 1μs track speed di / dt greater than 50A / μs 6, this excellent dynamic performance Hall sensor module to improve the performance of modern control systems provide a key foundation. This response time compared to conventional transformers 10-12ms, it can not meet the need to work to control system development. 7, frequency band: 0-100kHz frequency range within an accuracy of 1%. 0-5kHz frequency range within the accuracy of 0.5%. 8, measuring range: Hall sensor module system products, current measurements up to 50KA, voltage measurement up to 6400V. 9, strong overload: When the primary current overload, the module reaches saturation, automatic protection, even if overload is 20 times the rated current, the module will not be damaged. 10, small module size, light weight, easy to install, it will not bring any loss in the system. 11 "Capacitive" between primary and secondary module is weak, in many applications, a variety of common mode voltage can usually be ignored, when several thousand volts high voltage change / μs, the module has its own shielding effect of X-ray machine maintenance. 12, high sensitivity module, making it possible to distinguish between "high weight" on weak signals, such as: the DC component of the hundreds of security distinguish the AC component of a few milliamperes. 13 High reliability: failure rate: λ = 0.43╳10-6 / h 14, the external magnetic field strong anti-interference ability: There is a double magnetic current operating current (2Ip) arising from the module in place 5-10cm Interference caused by error of less than 0.5%, which for most applications, resistance to external magnetic interference is adequate, but the interference of strong field to take appropriate measures. [2]