CN2566281Y - Three-dimensional digital Hall magnetic field measuring device - Google Patents

Abstract

The utility model relates to a three-dimensional digital Hall magnetic field measuring device, which belongs to the technical field of the measurement of a three-dimensional constant magnetic field. The utility model is characterized in that the three-dimensional digital Hall magnetic field measuring device comprises two high-accuracy module conversion chips connected with the output terminal of a three-dimensional Hall chip, a single chip computer connected with the two high-accuracy module conversion chips, a setup signal chip selection logic circuit with an input terminal connected with the single chip computer and output terminals respectively connected with the two high-accuracy module conversion chips, a signal gating logic circuit with input terminals respectively connected with the two high-accuracy module conversion chips and an output terminal connected with the single chip computer, and an interruption signal gating logic circuit with input terminals respectively connected with the two high-accuracy module conversion chips and an output terminal connected with the single chip computer. The measuring instrument has the advantages of high accuracy, high resolution capacity, electricity saving and high efficiency. The utility model fills the blank of high-accuracy measuring products for the three-dimensional magnetic field in China.

Description

3-dimensional digital formula Hall magnetic field measuring instrument

Technical field:

A kind of 3-dimensional digital formula Hall magnetic field measuring instrument relates to three-dimensional stationary magnetic field field of measuring technique.

Background technology:

Compare with the traditional analog meter, the digital magnetic field measuring instrument can both reach unexistent measuring accuracy of analogy method and accuracy aspect Weak magentic-field measurement and the high frequency magnetic field measurement.Abroad, developed three-dimensional Hall chip of new generation, and be widely used in the occasion such as the detection of homogeneity not damaged, disk running speed measurement of superconduction, and the accuracy that is beyond one's reach of one dimension magnetic field measuring apparatus has been arranged.

At document " Title:Method for offset-compensated magnetic field measurement using Hall sensor; Involves obtaining measuring signals at two sensitivities and using equation to determine offsetInventor Name (s): FISCHER R, MAECKEL R, SCHULZ T Patent Assignee Name (s) andCode (s): DAIMLERCHRYSLER AG (DAIM) Derwent Primary Accession Number:2000-664789[49] " (" method of adopting Hall element to carry out the bias compensation magnetic-field measurement: adopt dual sensitivity to obtain measuring-signal; Adopt formula to determine amount of bias " inventor's name: FISCHER R; MAECKEL R; SCHULZ T; patent is accepted name and code: AIMLERCHRYSLER AG (DAIM); Derwent general data: 2000-664789[49] in "), adopt amplifier (error) behind the hall device, can cause the analog signal conditioner deficiency like this, thereby can not get higher resolution.

In the literature search, do not retrieve the document of relevant three-dimensional Hall magnetic field measuring instrument circuit aspect outside, at home, also do not have high accuracy three-dimensional numeral Hall magnetic field measuring instrument product at present.

The utility model content:

3-dimensional digital formula Hall magnetic field measuring instrument provided by the utility model, adopted three-dimensional Hall chip that magnetic field is detected, and introduced a kind of high precision digital-to-analog converter (ADC), utilize its compensating analog signal condition deficiency, make measuring instrument resolution improve, the signal after the digital conversion is sent in the single-chip microcomputer and is handled, thereby records the magnetic field of X, Y, Z three directions, also adopted simultaneously and a kind ofly can improve power supplying efficiency, the power supply of lengthening working hours.

3-dimensional digital formula Hall magnetic field measuring instrument provided by the utility model, contain metering circuit, power supply and LCD MODULE based on three-dimensional Hall chip, it is characterized in that described metering circuit contains: two high precision analogue conversion chip U2A and U2B that its input end links to each other with the output terminal of above-mentioned three-dimensional Hall chip respectively; Its gating signal input end respectively with the x direction magnetic field B x of above-mentioned two high precision analogue conversion chip U2A, the y direction magnetic field B y of z direction magnetic-field component Bz1 and U2, the single-chip microcomputer that two groups of signal output parts of z direction magnetic-field component Bz2 link to each other; Its input end selects output terminal to link to each other with the signalization sheet of above-mentioned single-chip microcomputer, and the signalization chip select logic circuit (1) that output terminal links to each other with the signalization input end of above-mentioned two high precision analogue conversion chips respectively; Its input end links to each other with the gating signal output terminal of above-mentioned two high precision analogue conversion chips respectively, and the signal gating logical circuit (2) that output terminal links to each other with the gating signal input end of above-mentioned single-chip microcomputer respectively; Its input end links to each other with the request look-at-me output terminal of above-mentioned two high precision analogue conversion chips respectively, and the look-at-me gate logic circuit (3) that output terminal links to each other with the look-at-me input end of above-mentioned single-chip microcomputer.

Above-mentioned signalization chip select logic circuit (1) is formed with door U3A and U3B by two, the common signalization output terminal that connects above-mentioned single-chip microcomputer of its input end separately, another input end connects two chip selection signal output terminals of above-mentioned single-chip microcomputer respectively, and its output terminal connects described two high precision analogue conversion chips signalization input end separately respectively.

Above-mentioned signal gating logical circuit (2) is made up of three rejection gate U4A, U4B and U4C, wherein U4A and a U4B input end separately are connected By, the Bz2 signal output part of Bx, Bz1 signal output part and the U2B of described high precision analogue conversion chip U2A respectively, its another input end connects two chip selection signal output terminals of described single-chip microcomputer respectively, and two output terminals link to each other with the input end of U4C, and the output terminal of U4C links to each other with the gating signal input end of described single-chip microcomputer.

Above-mentioned look-at-me gate logic circuit (3) is made up of three Sheffer stroke gate U5A, U5B and U5C, wherein U5A links to each other with the request look-at-me output terminal of described two high precision analogue conversion chips respectively with a U5B input end separately, another input end links to each other with two interruption gating signal output terminals of described single-chip microcomputer respectively, and two output terminals link to each other with the input end of U3C, and the output terminal of U3C links to each other with the look-at-me input end of described single-chip microcomputer.

Above-mentioned power supply contains: the chopper circuit of being made up of a CMOS step down switching voltage regulator chip P1 and typical peripheral circuit thereof (4) that its input end links to each other with battery; The filtering circuit (5) that its input end links to each other with the output terminal of described chopper circuit (4); Its input end links to each other with the output terminal of described filtering circuit (5), and the pi-network (6) that output terminal links to each other with the aanalogvoltage or the digital voltage input end of relevant chip; The voltage reversal chip P2 that its input end links to each other with the voltage output end of described filtering circuit (5); Its input end links to each other with battery, and output terminal links to each other with the current input terminal of described three-dimensional Hall chip, with the chip P3 of output steady current.

The model of above-mentioned three-dimensional Hall chip is 3D-H-30, and the model of two high precision analogue conversion chips is Max1400, and the model of single-chip microcomputer is AT90S8515.

The model of step down switching voltage regulator chip P1 in the above-mentioned power supply is MAX638, and the model of voltage reversal chip P2 is MAX660, and the model that produces the chip P3 of steady current is REF02.

Experimental results show that, 3-dimensional digital formula Hall magnetic field measuring instrument provided by the utility model can record the magnetic field of X, Y, Z three directions, shortcoming that simultaneously can compensating analog signal condition deficiency, make measuring instrument resolution improve, the power supply of its use can also improve power supplying efficiency, lengthen working hours, reached its intended purposes.

Description of drawings:

Fig. 1 is the measuring instrument schematic block circuit diagram;

Fig. 2 is the measuring instrument circuit theory diagrams, divides to be drawn on two pages of paper, and its circuit connecting relation and signal circulating direction are by arrow and corresponding

Character indicate;

Fig. 3 is power circuit principle figure.

Embodiment:

As shown in Figure 1:

Three-dimensional hall probe detects field signal in magnetic field after, signal is sent into high-precision adc ADC1 and ADC2, with the gating of the digital quantity after the conversion by logical circuit, send in the single-chip microcomputer (MCU) and handle, the data after handling are shown on LCDs by LCD MODULE; Also contain the power supply that supplies each chip operation in the measuring instrument and can realize the supervisory keyboard that various functions are switched.

The model of each chip and annexation are seen Fig. 2 and Fig. 3.

What 1) three-dimensional Hall chip adopted is the 3D-H-30 type Hall chip that Sentron company produces, and its key technical indexes is as follows:

Nominal Control current: 3mA

Sensitivity (Control current 3mA): x, y direction 275mV/T

Z direction 100mV/T is under the effect of Control current, chip produces 4 road voltage signal SX1, SX2, SY1, SY2, can obtain the magnetic field of x, y, z direction by computing, i.e. four tunnel differential voltage Bx=Sx1-Sx2, By=SY1-SY2, Bz1=SX1-SY1, Bz2=SX2-SY2, and Bz=Bz1+Bz2.Wherein the calculating of Bx and Bz1 is carried out in high precision analogue conversion chip ADC1, and the calculating of By and Bz2 is carried out in high precision analogue conversion chip ADC2, and the calculating of Bz=Bz1+Bz2 is carried out in single-chip microcomputer.

2) the MAX1400 cake core that the high precision analogue conversion chip that the utility model adopted is, integrated multiway analog switch in the MAX1400 chip.By analog switch, the MAX1400 chip can be realized the conversion to 3 tunnel differential voltages, thereby provides convenience for further simplifying outside mimic channel.The MAX1400 chip has been realized the digital filter in the sheet, by the trap frequency of wave filter suitably is set, can effectively suppress power frequency and high frequency interference, is particularly suited for the measurement of low frequency and DC voltage.The interface of MAX1400 chip and single-chip microcomputer is SPI (Serial Peripheral Interface (SPI)) structure.By the read-write to each register of chip internal, the user can be provided with the PGA gain respectively to each differential voltage passage, and parameters such as wave filter trap frequency are provided with, and have very high dirigibility.The PGA gain of MAX1400 chip and the method to set up of wave filter trap frequency clearly demonstrate in MAX1400 chip operation instructions.

The major function of MAX1400 chip is that the input simulating signal is carried out the AD conversion, and with four drive test amount signal SX1, SX2, SY1, SY2 is converted into X, Y, the magnetic field amount of Z direction.Because a slice MAX1400 chip can only be imported three tunnel differential voltages (AIN1 of Fig. 2 chips～AIN6 end is the input end of three tunnel differential voltages), if only just need add analog switch handover measurement passage with a slice MAX1400 chip, can introduce more imbalance and noise like this, and the speed that reading refreshes also can be slack-off owing to the reduction of each channel measurement frequency.The utility model adopts two MAX1400 chips, only imports the two-way differential voltage signal for every, need not external analog switch, can solve this problem.The AIN1 of MAX1400 chip～AIN4 pin is respectively to be two groups of difference analogue data input pins on reference ground with AIN6 among Fig. 2, and the DOUT output terminal of chip is exported the AIN1-AIN2 after the AD conversion, AIN3-AIN4 signal successively.The DOUT of ADC1 end output digital quantity Bx=SX1-SX2 in the utility model, Bz1=SX1-SY1; The DOUT end output digital quantity By=SY1-SY2 of ADC2, Bz2=SX2-SY2.The computing of Bz=Bz1+Bz2 realizes in single-chip microcomputer.

The peripheral resistance of MAX1400 chip and electric capacity R1, the circuit that C1 constitutes is the input auxiliary circuit, the C1 voltage stabilizing, R1 limits input current; Other analog structure effects roughly the same; Resistance R 9, R10 is typical connection, no datat external treatment between expression MUXOUT end and the ADCIN end.

3) single-chip microcomputer (MCU) adopts 8 single-chip microcomputers of AT90S8515 type of Atmel company.Because adopt Harvard structure and reduced instruction set computer (RISC), this single-chip microcomputer can be finished an instruction in a clock period, improve more than 5 times than traditional 8 motor speed of 51 series.Have 48 I/O mouths, can pull-up resistor in input, output and the sheet be set respectively each I/O pin, powerful to the control function of peripherals.The high speed SPI interface that it had can be connected with the MAX1400 chip easily.It has two kinds of sleep patterns, can enter sleep state to reduce power consumption and to the interference of ADC when high precision analogue conversion chip ADC changes.

4) in being connected of two MAX1400 chips and single-chip microcomputer, need to consider that single-chip microcomputer carries out the gating setting to the mode of operation of ADC chip, its data output signal and look-at-me are carried out the problem of gating.Because every kind of signal has only two-way to need gating, in order to keep dirigibility, native system is without data selector but adopt two common inputs to carry out gating with door, Sheffer stroke gate and rejection gate.(1) ADC is received single-chip microcomputer MOSI port and export " signalization chip select logic circuit (1) " shown in gating employing Fig. 2 of signalization, this circuit is formed with door by two, its model is 7408, its annexation as shown in the figure, logical expression is:

DIN1＝ CS1·MOSI

DIN2＝ CS2·MOSI

The result is as shown in table 1 for its gating:

CS1	CS2	MOSI->DIN
			1	0	ADC1 work, MOSI-〉DIN1
0	1	ADC2 work, MOSI-〉DIN2

(2) gating of adc data output signal is adopted " signal gating logical circuit (2) " shown in Fig. 2, this circuit is made up of three rejection gates, and its model is 7428, its annexation as shown in the figure, logical expression is: $\mathrm{ADOUT}=\stackrel{﹠OverBar;}{\stackrel{﹠OverBar;}{\stackrel{﹠OverBar;}{\mathrm{<figure-callout\; id="1"\; label="ADCS"\; filenames="Y0223753700111.png"\; state="\{\{state\}\}">ADCS</figure-callout>}1}+\mathrm{ADOUT}1}+\stackrel{﹠OverBar;}{\stackrel{﹠OverBar;}{\mathrm{ADCS}2}+\mathrm{<figure-callout\; id="2"\; label="ADOUT"\; filenames="Y0223753700111.png"\; state="\{\{state\}\}">ADOUT</figure-callout>}2}}$

ADCS1 wherein, ADCS2 are the gating signal of single-chip microcomputer output, ADOUT1, ADOUT2 be ADC1 and

The data output signal of ADC2.The result is as shown in table 2 for its gating:

ADCS1	ADCS2	ADOUTV
			0	1	ADOUT1
1	0	ADOUT2

Table 2 (3) adopts " the look-at-me gate logic circuit (3) " shown in Fig. 2 to the gating of ADC look-at-me, and this circuit is by three

Individual Sheffer stroke gate is formed, and its model is 74LS00, and logical expression is: $\stackrel{\&OverBar;}{\mathrm{ADINT}}=\stackrel{\&OverBar;}{\stackrel{\&OverBar;}{\stackrel{\&OverBar;}{\mathrm{ADINT}1}\&CenterDot;\mathrm{INTMASK}1\&CenterDot;\stackrel{\&OverBar;}{\mathrm{ADINT}2}\&CenterDot;\mathrm{INTMASK}2}}$

INTMASK1 wherein, INTMASK2 are the gating signal of single-chip microcomputer output.ADINT1, ADINT2 are ADC

Look-at-me, the result is as shown in table 3 for its gating:

INTMASK1	INTMASK2	ADINT
			1	0	ADINT1
0	1	ADINT2
			1	1	ADINT1+ ADINT2
0	0	Trigger and interrupt

Table 3

5) LCD MODULE adopts the MDLS-81809 chip, is used to show the information of reading and operation, and its 4 bit parallel data transmission mouth links to each other with the PC4～PC7 of singlechip chip, receives the data of single-chip microcomputer transmission.

U7 accuses the system keyboard among Fig. 2, each keyswitch on S1～S5 keyboard, an output terminal of switch connects the PA0～PA4 end of singlechip chip respectively, another output terminal connects the keyboard interrupt signal input end INT1 of singlechip chip jointly, each keyswitch is carried out following function respectively, and the realization of its function is to realize by programming in single-chip microcomputer.The S1:HOLD button, reading keeps function: the reading of magnetic field instrument is in the state of continual renovation during power connection.Press HOLD

Button, the reading demonstration of magnetic field instrument stops to upgrade; Discharge the HOLD button, the reading of magnetic field instrument restarts to upgrade.The S2:RANGE button, switching range; Range is at 1999mT, 199.9mT, circulation change between the 19.99mT.The S3:BY button switches three peacekeeping one-dimensional measurement functions; During power connection, what the magnetic field instrument showed is closing of space three-dimensional magnetic field

Vector size B is next whenever by a button, according to the sequential loop demonstration of By, Bx, Bz, B.The S4:ZERO button, user school zero power energy; If the user needs again school zero, then should place zero magnetic to the magnetic field instrument probe

In the box, press the ZERO button, then press the HOLD button again, the magnetic field instrument automatically to each channel correcting zero point (User ' s

Offset), zero data is stored among the EEPROM simultaneously, uses next time and still can recover the zero point that last user is proofreaied and correct.The S5:RESET button, recovery system function at zero point; If want to recover (the System at zero point that process metrological service calibrated

Offset), then press the RESET button, then press the HOLD button again, the magnetic field instrument was calibrated with regard to the recovery use like this

Zero point.

6) as shown in Figure 3, because traditional linear voltage stabilization module (as 7805) is operated in+efficient too low (near 50%) of 9V under the operating mode of+5V, battery working time is very unfavorable for prolonging, and is difficult to reach the requirement of system's ease for use.The power supply mode that this measuring instrument adopts mainly is the 9V laminated cell, utilizes the MAX638 type CMOS step down switching voltage regulator chip realizations+9V (cell voltage) of Maxim company to arrive+conversion of 5V, to each chip power supply in the system.

MAX638 type CMOS step down switching voltage regulator chip has that conversion efficiency height (more than 90%), outward element are few, the advantage of Adjustable Output Voltage, can significantly reduce electric energy loss, realize the high request of magnetic field measuring apparatus to power saving, cell voltage detected automatically when simultaneously, its low-voltage measuring ability can be realized starting shooting.Its shortcoming is that mainly output voltage has big ripple, for high-precision measuring system certain influence is arranged, thus need to adopt rational component parameters and suitable filtering link, to obtain good power quality.The utility model adopts chopper circuit to realize filtering, stablizes output waveform.

Among the illustrated power circuit principle figure, + 9V voltage is reduced to+5V voltage through the chopper circuit (4) that MAX638 chip and peripheral electric capacity, inductance and diode constitute ,+5V voltage after filtration wave circuit (5) and pi-network (6) output aanalogvoltage and digital voltage for each element use.Voltage output end at chopper circuit is connected with voltage reversal chip MAX660, and general+5V voltage transitions is-5V.Simultaneously the LBO of MAX638 chip end is also drawn signal wire LOBAT, and when cell voltage drops to 8V when following, LOBAT can become low level by high level, and system detects the cell voltage situation automatically when can be used for starting shooting, and LOBAT links to each other with the PA5 end of singlechip chip.The REF02 chip that is adopted in the power supply can produce+and the steady current of 5A, use for Hall chip.

Claims (11)

1,3-dimensional digital formula Hall magnetic field measuring instrument, contain magnetic-field measurement circuit, power supply and LCD MODULE based on three-dimensional Hall chip, it is characterized in that described magnetic-field measurement circuit contains: two high precision analogue conversion chip U2A and U2B that its input end links to each other with the output terminal of above-mentioned three-dimensional Hall chip respectively; Its gating signal input end respectively with the x direction magnetic field B x of above-mentioned two high precision analogue conversion chip U2A, the y direction magnetic field B y of z direction magnetic-field component Bz1 and U2, the single-chip microcomputer that two groups of signal output parts of z direction magnetic-field component Bz2 link to each other; Its input end selects output terminal to link to each other with the signalization sheet of above-mentioned single-chip microcomputer, and the signalization chip select logic circuit (1) that output terminal links to each other with the signalization input end of above-mentioned two high precision analogue conversion chips respectively; Its input end links to each other with the gating signal output terminal of above-mentioned two high precision analogue conversion chips respectively, and the signal gating logical circuit (2) that output terminal links to each other with the gating signal input end of above-mentioned single-chip microcomputer respectively; Its input end links to each other with the request look-at-me output terminal of above-mentioned two high precision analogue conversion chips respectively, and the look-at-me gate logic circuit (3) that output terminal links to each other with the look-at-me input end of above-mentioned single-chip microcomputer.

2,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: described signalization chip select logic circuit (1) is formed with door U3A and U3B by two, the common signalization output terminal that connects above-mentioned single-chip microcomputer of its input end separately, another input end connects two chip selection signal output terminals of above-mentioned single-chip microcomputer respectively, and its output terminal connects described two high precision analogue conversion chips signalization input end separately respectively.

3,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: described signal gating logical circuit (2) is made up of three rejection gate U4A, U4B and U4C, wherein U4A and a U4B input end separately are connected By, the Bz2 signal output part of Bx, Bz1 signal output part and the U2B of described high precision analogue conversion chip U2A respectively, its another input end connects two chip selection signal output terminals of described single-chip microcomputer respectively, and two output terminals link to each other with the input end of U4C, and the output terminal of U4C links to each other with the gating signal input end of described single-chip microcomputer.

4,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: described look-at-me gate logic circuit (3) is made up of three Sheffer stroke gate U5A, U5B and U5C, wherein U5A links to each other with the request look-at-me output terminal of described two high precision analogue conversion chips respectively with a U5B input end separately, another input end links to each other with two interruption gating signal output terminals of described single-chip microcomputer respectively, and two output terminals link to each other with the input end of U3C, and the output terminal of U3C links to each other with the look-at-me input end of described single-chip microcomputer.

5,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that described power supply contains: the chopper circuit of forming by a CMOS step down switching voltage regulator chip P1 and typical peripheral circuit thereof (4) that its input end links to each other with battery; The filtering circuit (5) that its input end links to each other with the output terminal of described chopper circuit (4); Its input end links to each other with the output terminal of described filtering circuit (5), and the pi-network (6) that output terminal links to each other with the aanalogvoltage or the digital voltage input end of relevant chip; The voltage reversal chip P2 that its input end links to each other with the voltage output end of described filtering circuit (5); Its input end links to each other with battery, and output terminal links to each other with the current input terminal of described three-dimensional Hall chip, with the chip P3 of output steady current.

6,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: the model of described three-dimensional Hall chip is 3D-H-30.

7,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: the model of described two high precision analogue conversion chips is Max1400.

8,3-dimensional digital formula Hall magnetic field measuring instrument as claimed in claim 1, it is characterized in that: the model of described single-chip microcomputer is AT90S8515.

9, as claim 1 or 5 described 3-dimensional digital formula Hall magnetic field measuring instruments, it is characterized in that: the model of the CMOS step down switching voltage regulator chip P1 in the described power supply is MAX638.

10, as claim 1 or 5 described 3-dimensional digital formula Hall magnetic field measuring instruments, it is characterized in that: the model of the voltage reversal chip P2 in the described power supply is MAX660.

11, as claim 1 or 5 described 3-dimensional digital formula Hall magnetic field measuring instruments, it is characterized in that: the model that produces the chip P3 of steady current in the described power supply is REF02.

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