What does a magnetic grid sensor consist of?

Compose. A magnetic grid sensor consists of a magnetic grid, a magnetic head, and a detection circuit.

Magnetic grids. The magnetic grid is made by coating a uniform magnetic film on the grid base made of non-magnetic material, and recording the magnetic signal grid with equal spacing and positive and negative polarity. In the diagram, n n and s s are positive and negative polarity, respectively.

Head. There are two types of heads: dynamic heads (velocity response heads) and static heads (flux response heads). The dynamic head has an output winding, and the signal output can only be obtained when the head and gate are in relative motion.

The static head has two windings, excitation and output, and it can also have signal output when it is stationary relative to the magnetic grid. Static magnetic heads are multi-gap cores with unequal effective cross-sections stacked with iron-nickel alloy sheets. The excitation winding acts as a magnetic switch.

When alternating current, the magnetic circuit with a smaller core cross-section is excited twice a week to produce magnetic saturation, so that the magnetic field lines generated by the grating cannot pass through the core. Only when the excitation current crosses zero twice a week, the core is not saturated, and the magnetic field lines of the grating can pass through the core. At this point, the output winding has an induced potential output.

Its frequency is twice the frequency of the excitation current, and the amplitude of the output voltage is proportional to the magnetic flux entering the core, i.e., the position of the head relative to the magnetic grid. The head is made with multiple gaps to increase the output, and the output signal is the average of the signals obtained by multiple gaps, so the output accuracy can be improved. Static heads are always used in pairs with a spacing of (m+1 4), where m is a positive integer, which is the spacing of the grid bars.

The excitation current or phase of the two heads is the same, or 4 apart. The output signal can be processed by the phase detection circuit or amplitude recognition circuit to obtain a digital output proportional to the measured displacement.

The sensor is generally composed of three parts: the sensitive and intelligent sensing element, the conversion element and the signal conditioning conversion circuit. Towns and occasionally, an auxiliary power supply is required to provide conversion energy.

A sensitive element is the part of the sensor that directly senses or responds to a measurement. The conversion element is the part of the sensor that converts the measured signal perceived or responded to by the sensitive element into an electrical signal suitable for transmission or measurement. Because the output signal of the sensor is generally weak, the output signal of the sensor generally needs to be conditioned, converted, amplified, calculated and modulated before it can be displayed and controlled.

1] With the application of semiconductor devices and integrated technologies in sensors, sensor modules and integrated circuit sensors, such as integrated temperature Punkai sensors AD590, DS18B20, etc. The signal conditioning and conversion circuitry of the sensor is integrated with the sensitive components on the same chip.

The sensor is generally composed of three parts: a sensitive element, a conversion element, and a signal conditioning conversion circuitand sometimes an auxiliary power supply is required to provide the conversion energy. It can feel the measured information, and can transform the felt information into electrical signals or other required forms of information output according to a certain law, so as to meet the requirements of information transmission, processing, storage, display, recording and control.

The characteristics of the sensor include: miniaturization, digitization, intelligence, multi-functional source, systematization, and networking. It is the first link to realize automatic detection and automatic control.

The existence and development of sensors allow objects to have senses such as touch, taste, and smell, allowing objects to slowly become alive.

The main role of the sensor

in basic disciplines.

In the research, the sensor has a more prominent position. The development of modern science and technology has entered many new fields: for example, it is necessary to observe the vast universe of thousands of light years on the macroscopic scale, the particle world as small as fm on the microscopic level, the evolution of celestial bodies as long as hundreds of thousands of years in the longitudinal direction, and the instantaneous reaction as short as s.

In addition, there are also various extreme technologies that play an important role in deepening the understanding of matter, developing new energy and new materials, such as ultra-high temperature, ultra-low temperature, ultra-high pressure, ultra-high vacuum, ultra-strong magnetic field, ultra-weak magnetic field, hail pie, and so on. Obviously, it is impossible to obtain a large amount of information that cannot be directly obtained by the human senses without appropriate sensors.

Many basic scientific researches.

The first obstacle is that there is a difficulty in obtaining information about the target finger, and the emergence of some new mechanisms and high-sensitivity detection sensors often leads to breakthroughs in this field. The development of some sensors is often the forerunner of the development of some marginal disciplines.

Magnetic sensors, commonly known as magnetic switches, are mainly composed of magnetic sensing elements and electronic circuits. Through the characteristics of magnetic sensing element to magnetic induction, the position of the magnetic ring moving with the piston in the cylinder is detected, and then the purpose of detecting the action position of the piston rod is achieved; InAutomatic control systemIt can be used for functions such as limit, counting, positioning control and automatic protection.

According to the design principle of magnetic switches, they can be divided into two types: with contacts (reed reed) and without contacts (electronic solid state).

The principle of a contact (reed reed) magnetic switch is that through the two reeds in the reed, when the magnetic field is sensed, magnetize and engage each other, and then mechanically contact the conduction circuit and send out an electronic signal; And when the strength of the magnetic field.

When it weakens and is too low to maintain the strength of the reed engagement, the two reeds pop open and the switch is disconnected.

The advantage is that it can adapt to a wide voltage range, withstand voltage up to 240 volts, and can be applied to AC and DC.

The disadvantage is that the glass of the reed tube is thin and fragile, and the slightest collision will cause the sensitivity to change, and the switch will also malfunction, and the stability is poor.

The contactless magnetic switch is made of all-electronic components.

The principle is through a dedicated magnetic resistance.

The characteristics of the IC detect the position of the magnetic ring in the cylinder and output actuation and switching signals. Compared with the magnetic reed type, the electronic magnetic switch has the advantages of higher sensing accuracy, no malfunction, anti-vibration, anti-shock and long service life. The disadvantage is that it can withstand a low voltage, and most contactless switches can only be applied to a voltage of 30 volts DC.

However, in 2020, the ALIF brand has successfully developed an electronic switch codenamed "DFV", which can withstand high voltages up to 240 volts and is suitable for both DC and AC currents.

It is a perfect replacement for technologically outdated and fragile reed switches.

The grating sensor is generally composed of 6 major parts.

1.Emitter: composed of several light-emitting devices, emitting infrared light;

2.Receiver: It is composed of a plurality of light-receiving devices, which accepts infrared rays and corresponds to the light-emitting devices of the transmitter one-to-one, forming a protective light curtain, generating a light and shading signal, and at the same time transmitting the signal to the controller through the signal cable to control the external equipment;

3.Controller: the signal processing unit, which provides power supply for the transmitter and receiver, and receives the light and shading signals transmitted by the receiver, generates output control signals, controls the brake control loop of the machine tool or the alarm device of other equipment, and realizes the machine tool stop operation or safety alarm;

4.Control cable: used to connect the controller with the machine tool and equipment to achieve the safety control of the machine tool or other equipment;

5.Signal cable state answer: used to transmit the signal between the controller and the luminaire and the light receiver;

6.Mounting bracket: fix the emitter and the light receiver on the machine to realize the up and down, left and right direction adjustment of the transmitter and receiver.

The sensor is generally composed of four parts: a sensitive element, a conversion element, a conversion circuit and an auxiliary power supply.

1. The sensitive element directly feels the measured and outputs the physical quantity signal that has a definite relationship with the measurement;

2. The conversion element converts the physical quantity signal output by the sensitive element into an electrical signal;

3. The conversion circuit is responsible for amplifying and modulating the electrical signal output by the conversion element;

4. Conversion components and conversion circuits generally need auxiliary power supply.

The characteristics of the sensor include: miniaturization, digitization, intelligence, multi-functionalization, systematization, networking, it not only promotes the transformation and upgrading of traditional industries, but also establishes a new type of industry, thus becoming a new economic growth point in the 21st century.

1. The magnetoelectric sensor is a sensor that uses the principle of electromagnetic induction to convert the input motion speed into the output of the induced electric potential. It is an active sensor that converts the mechanical energy of the measured object into an easy-to-measure electrical signal without the need for auxiliary power supply.

2. Magnetoelectric sensors are sometimes called motorized or inductive sensors, which are only suitable for dynamic measurements. Because it has a large output power, the matching circuit is relatively simple, and the zero position and performance are stable. According to this principle, it can be designed into two structural types, variable flux type and constant flux type, to form a magnetoelectric sensor for measuring linear velocity or angular velocity.