Magnetic encoder structure and the working principle of the magnetic encoder
Magnetic encoder is a new type of sensors in use distance measuring Angle displacement speed device, today let's learn about the magnetic encoder structure and the working principle of the magnetic encoder.
Magnetic encoder structure main parts by the magnetic resistance sensor, the magnetic encoder of drum, the signal processing circuit.
Drum burn into evenly spaced small magnetic poles, pole after being magnetized, leakage magnetic field generated when the rotation cycle of the distribution of space.
Magnetic sensor probe through the magnetoresistance effect changing magnetic field signal can be converted to the change of the resistance tolerance, under the action of applied electric potential, the change of the change of the resistance value is converted into voltage, following the processing of the signal processing circuit, analog voltage signal into digital signal, the computer can identify the implementation code function of the magnetic rotary encoder.
The magnetization of the magnetic drum is designed to make the small pole of drum will be magnetized, such as motor rotating the magnetic drum, drum can produce periodic change space magnetic flux leakage, effect on the magnetic resistance, coding for function.
The number of drum magnetic poles determines the resolution of the encoder, the uniformity of drum magnetic pole and remanence intensity is important parameter in determining the quality of the encoder structure and output signal.
Magnetic resistance sensor is magnetic resistance sensor, the magnetic resistance devices can be divided into strong magnetic reluctance and semiconductor magnetic resistance components.
In order to improve the sensitivity of signal sampling, at the same time, considering the structure of differential compensation effect of the temperature characteristic of sensor, generally in the magnetization spacing & lambda;
2 bits, etching differ for 丌 / 2 stripes, a half bridge series network.
At the same time, in order to improve the resolution of the encoder, which can be on the head with multiple magnetic resistance sensor, under the condition of the applied voltage, magnetic resistance element through the drum rotating corresponding sine wave output.
Its principle is simple explanation: drum NS of the magnetic field generated a circular motion, sensor made of magnetic resistance element with the magnetic field changes the resistance changes, and to determine the SinA, SinB two voltage waveform.
Magnetic resistance sensor structure as shown in figure, the eight magnetic resistance is divided into two groups are separated by a quarter NS spacing.
In Mr1, Mr2 and Mr3 Mr4 contact place can check out the sine voltage waveform, the same principle in Mr1 ', Mr2 'and Mr3' Mr4 'SinB contact point can be detected voltage waveform.
From the magnetic resistance sensor output waveform signal processing circuit, two road, SinA SinB signal to the signal processing circuit, in order to be within the scope of the CPU sampling, need to adjust the waveform.
AB believe no need to do first must adjust, DC voltage DC must convince AB, who is located in the DSP, A/D sampling the halfway point of the voltage range, and the amplitude is less than the sample voltage range, AB believe that through the analog filter and digital filter, the high frequency and harmonic filter, high speed operation ability in real time by DSP will calculate the position and speed;
There is also a kind of treatment method is to directly by SinA, SinB signal after converting ChengFangBo DSP signal processing circuit.
The latter may more convenient to handle some software.
Working principle of the magnetic encoder is a new type of magnetic encoder Angle or displacement measuring system, its principle is to use magnetic resistance or element to change to measure the Angle or displacement values of magnetic materials, magnetic materials Angle or displacement change will cause a certain resistance or voltage changes, through single chip microcomputer or analog signal output pulse signal after processing, to achieve the purpose of measuring.
Concentric code, starting from the center of the magnetic encoder encoder, extending outward until the encoder outside, each layer of code that is a times more than its inner partition.
The first layer is only a light sectors and an opaque sector, is located on the second floor of the center has two transmission sector and opaque sector;
And the third layer code of pervious to light sectors and opaque sector will each have four.
Embedded sensing head volume is small, be applicable to the small installation space, and USES the high level of protection design, can use in the bad environment, in industrial situations can avoid the sensitivity of the general optical environment pollution, increase the system stability.
Magnetic encoder by A central shaft of light code disc, on which there are circular and dark scribed line, have read photoelectric emission and receiving devices, obtain four groups of sine wave signal is combined into A, B, C, D, each phase sine wave by 90 degrees, will reverse, C, D signal superimposed on A, B two phase, can strengthen stability of signal;
Every turn output another Z pulse to represent a zero reference.
Because of A, B two phase difference of 90 degrees, but only through A phase in the former or B phase in the former, with forward and inversion of magnetic encoder, through the zero pulse, can obtain the zero reference.
Magnetic encoder code disc material with glass, metal, plastic, glass encoder is in the deposition of thin scribed line on the glass, its thermal stability, high precision, metal encoder directly to scribe lines and impassability, but because has certain thickness of metal, precision is limited, its thermal stability is an order of magnitude worse than glass, plastic encoder is economical.
Shanghai electronics is 26 years old coder manufacturer, specializing in the production of various types of rotary encoder, research and development production of magnetoelectric encoder is a cost-effective rotary encoder, this magnetoelectric encoder performance not easily affected by dust and condensation;
Its simple and compact structure, non-contact, long life, high and low temperature resistance, resistance to vibration, fast response speed and lower cost, worth it!
Looking for magnetoelectric encoder manufacturer is looking for Shanghai electronic products co. , LTD.