CN2419605Y - Automatic range switching and zero resetting magnet measuring instrument - Google Patents

Abstract

The utility model relates to an automatic range limit and digital zero setting magnetism measuring instrument which is connected and assembled by a machine shell, an LCD display, a zero setting button, a magnetism measuring probe and a socket thereof and a circuit board. The utility model has the relationship that the circuit board is arranged in the machine shell; the LCD display, the zero setting button and the magnetism measuring probe socket are respectively arranged at the upper part, the middle upper part and the lower part of a machine shell panel and are respectively electrically connected with corresponding parts of the circuit board. A circuit of the magnetism measuring instrument is formed by the mutually electric connection of a magnetism measuring sensor composed of a current source and a magnetic-sensing source, a program control amplifier, a digital zeroing circuit, a memory circuit, a comparison circuit, an automatic latch range limit converting circuit, an A/D converter and an LCD display through respective signal lines and output lines. The magnetism measuring instrument takes the digital zero point zeroing circuit, and has the advantages of small volume, convenient carrying, stable performance, reliability, low cost, low power consumption, clear reading number and accuracy.

Description

The magnetometer of auto-range and digital zero setting

The utility model is the magnetometer of a kind of auto-range and digital zero setting, belongs to magnetosensitive sensing instrument.

Magnetometer is an instrument of measuring magnetic field intensity.The existing amount of the changing mode of surveying magnetic class instrument mainly contains manually two kinds of the amount of changing limits and auto-range: manually the amount of changing limit is to utilize the key switch of being with self-locking to wait the amplification coefficient of switch operation amplifier circuit; Auto-range, a kind of is to utilize one-chip computer to control lifting amount limit automatically, a kind of be output pulse signal with A/D converter as the quiescent voltage signal, realize auto-range by comparator circuit.Manually the shortcoming of the amount of changing limit is when the magnetic field intensity of Measuring Object, and each lifting amount limit all will make measuring operation loaded down with trivial details by the amount of the changing limit switch of an instrument; Advantage from the amount of moving is that adjustment amount is limit scope automatically, is convenient for measuring.The problem of surveying the existence of magnetic class instrument at present is: 1. utilize one-chip computer zeroising and auto-range, need to increase CPU and relevant interface circuit, both increased cost, strengthened the power consumption of circuit again, be unfavorable for portable (powered battery) magnetometer table especially, when being lower than the CMOS level as supply voltage, the magnetometer table phenomenon that can cause confusion; 2. the pulse signal with A/D converter output compares as the quiescent voltage signal, make its comparator circuit output level have labile factor, pulse is handled to have to disturb as quiescent voltage and is occurred, make that also arrive amount is not prescribed a time limit, therefore the phenomenon that the amount of changing limit occurs exists problem unstable, poor reliability; 3. present, all instrument and meters of measuring magnetic field all are to have adopted manually the directly method of regulator potentiometer, also the potentiometer of control enlargement factor will be installed on the instrument face plate.

The purpose of this utility model be exactly for overcome and solves existing magnetometer table exist utilize the single-chip microcomputer amount of changing limit and the zeroing circuit power consumption big, unfavorable portable, the cost height, and supply voltage is when being lower than the CMOS level, the magnetometer phenomenon that can cause confusion, the pulse signal of A/D converter output compared as the quiescent voltage signal can cause interference, exist unstable, the shortcoming and the problem of poor reliability or need hand reset etc., providing a kind of carries out digital processing to the pulse signal of A/D converter, adopt simulation to convert the zeroing circuit at digital zero point zero point to, make instrument function stable, reliably, cost is low, low in energy consumption, clear reading, accurately, volume is little, be beneficial to the magnetometer of portable auto-range and digital zero setting.

The utility model is realized by following technical proposals: the contour structures synoptic diagram of the magnetometer of auto-range and digital zero setting as shown in Figure 1; The survey magnetic probe of this magnetometer as shown in Figure 2; The circuit block diagram of this magnetometer as shown in Figure 3; Its circuit theory diagrams as shown in Figure 4.It is by casing 1,31/2 LCD LCD 2, zero-setting button 3, survey magnetic probe socket 4, survey magnetic probe, the common binding of circuit board assembles, its mutual alignment and annexation are: circuit board is fixedly installed in the casing 1, survey the magnetic probe cover and insert in survey magnetic probe socket 4,31/2 LCD LCD 2 is installed on the panel top of casing and is electrically connected mutually with corresponding A/D converter on the circuit board, zero-setting button 3 is installed on the middle and upper part of machine shell panel and is electrically connected mutually with circuit board respective digital zeroing circuit, survey magnetic probe socket 4 be installed on the machine shell panel bottom and with circuit board on corresponding programmable amplifier circuit be electrically connected mutually; Wherein: the survey Magnetic Sensor that the magnetometer circuit is made up of current source and magneto sensor, programmable amplifier, digital zero setting circuit, memory, comparison and latch auto-range circuit, A/D converter, LCD display and be electrically connected jointly and constitute, it is connected to each other to close and is: current source is electrically connected mutually by current source output line and magneto sensor and constitutes the survey Magnetic Sensor; Programmable amplifier respectively by survey Magnetic Sensor output signal line, digital zero setting circuit output signal line, memory, comparison and latch auto-range circuit control signal output line, program control signal output line respectively with survey Magnetic Sensor, digital zero setting circuit, memory, comparison and latch the auto-range circuit, A/D converter is electrically connected mutually, A/D converter respectively by the A/D converter output signal line respectively with LCD display and memory, comparison with latch the auto-range circuit and be electrically connected mutually; Wherein: survey Magnetic Sensor and be electrically connected jointly and constitute by operational amplifier U1A, triode N1, resistance R 1, current regulating resistance device W2, magneto sensor Hall; Programmable amplifier is by operational amplifier integration member U1C, U1D, multiway analog switch U8, adjustable resistor W _2T, W _200mT, resistance R 2, R4, R8～R10 be electrically connected formation jointly; The digital zero setting circuit is electrically connected jointly and is constituted by trigger flip-flop integration member U11A, simulation memory circuit integration member U5, resistance R 3, resistance R 18, pushbutton switch S1, capacitor C 5; Memory, relatively and latch the auto-range circuit and be electrically connected jointly than integrated circuit U3, U6, U7 and ungated integrated circuit U4D by rejection gate integration member U12A, U12B, U12C, U12D, numeric ratio and constitute; A/D converter is electrically connected jointly by double integral A/D converter integration member U10, adjustable resistor W1, resistance R 11～R13, capacitor C 1～C4, electrochemical capacitor C6 and constitutes; LCD display is made of LCD MODULE; Surveying magnetic probe is connected and composed jointly by magneto sensor (being Hall element) 5, copper pipe 6, handle 7, shielded cable 8, its interconnected relationship is: magneto sensor 5 connects with copper pipe 6, copper pipe 6 and handle 7 Joints, shielded cable 8 are electrically connected mutually with copper pipe 6 and survey magnetic probe socket 4 respectively.

The style of work principle and the circuit working principle thereof of this magnetometer are as follows: the circuit block diagram of magnetometer as shown in Figure 3, current source provides about 1～2mA stable current supply magneto sensor, its hall output voltage is input to programmable amplifier, the zero adjustment voltage of digital zero setting circuit also is input to programmable amplifier, programmable amplifier is with hall output voltage and adjust voltage zero point and carry out after difference amplifies, and is input to A/D converter and carries out outputing to LCD LCD after the A/D conversion and show.A/D converter is directly controlled " memory, relatively and latch the auto-range circuit " part in the meantime, and this part is controlled programmable amplifier again.Wherein: the magneto sensor of surveying Magnetic Sensor is selected the gallium arsenide Hall element for use, and as Hall among the figure, PIN1 and PIN2 are its current input terminals, working current≤2mA; PIN3 and PIN4 are its output voltage terminals; The digital zero setting circuit is made up of pulse producer U11A, simulation memory circuit (digital regulation resistance) U5 and resistance R 3.Need regulation meter during zero point, only need to press from reversion switch S1, pulsing circuit U11A will produce pulse output signals f at the PIN6 pin, enter circuit U 5, by the stable voltage of resistance R 3 outputs, the polarity of U5 output voltage is controlled by the polarity output terminal PIN20 of A/D converter U10, realizes regulating zero point by amplifier U1C at last; Memory, relatively and latch the start of auto-range circuit by the time original state be the minimum flow limit, i.e. 0～200mT amount limit.When the displayed value that outputs to LCD when the position of circuit U 8 was 1---, promptly instrument was in overload, just needed a liter amount limit, this moment comparator circuit U12D PIN11=1, triggering is by the rest-set flip-flop that U12B and U12C form, and makes the output pin PIN4=1 of U12B, control U8 gating W _2TDrive the PIN4 of U2 simultaneously, make the kilobit radix point of LCD display light.After circuit is raised to a large amount limit,, make U12B output PIN4=0 by U6, U7 and U12A through PIN3 control rest-set flip-flop, control U8 gating W if U10 outputs to the LCD displayed value when being 01xx _200mT, and ten radix point of control LCD display are lighted.Because rest-set flip-flop, after the R trigger end triggered, the R end triggered invalid again next time, had only the S end to trigger and just worked, and after promptly an end triggered, it was just effective to have only the other end to trigger.Kept state after the amount of the changing limit according to this characteristic; Multiway analog switch U8 and high performance amplifier U1D have formed programmable amplifier, adjustable resistor W _2TAnd W _200mTBe calibrated meter output, wherein W _200mTBe calibration 0～200mT amount limit scope, W _2TIt is calibration 0～2T amount limit scope.The A pin (PIN11) of U8 equals zero and chooses W _200mT, equal 1 and choose W _2TU10 is a double integral A/D converter, is the main product that the industrial automation instrument industry is adopted.Output directly drives three and half LCD display, and promptly kilobit numerical value is 0 and 1, hundred, picks up and the units value is 0～9, also has a sign bit PM, working current≤2mA.Input voltage has two scope: Vx=0～200mV, Vx=0～2V.

The utility model compared with prior art has following advantage and beneficial effect: 1. this magnetometer carries out digital processing to the field output pulse signal of 31/2 A/D converter, by memory, relatively and latch the auto-range circuit, automatically the control multi-channel analog switch circuit reaches the purpose that changes the amplifying circuit enlargement factor; 2. the zeroising circuit of " simulation zero point convert to numeral zero point " of this magnetometer, have stable and reliable for performance, avoided analog/digital (A/D) change-over circuit again, cost is low, also is distinctive feature of the present utility model.Digital regulation resistance U5 is direct and interface microcontroller, can not manually control, and the present invention is with trigger flip-flop U11A and A/D converter and U5 composition manual control circuit; 3. the utility model has all been selected cmos circuit for use, has particularly designed the reduction power digital circuit, makes low in energy consumptionly, and the maximum current≤1.6mA of amplification circuits adds the static current of lcd≤2mA of biproduct somatotype A/D converter, Overall Power Consumption electric current≤4mA again; 4. the utility model has adopted 1 inch LCD display, clear reading, accurate; Reading is SI units mT and T, and wherein mT is a milli tesla, and T is a tesla, 1T=1000mT=10000Gs; 5. the volume of this magnetometer is little, stable performance, reliable, and working current has reached the requirement of portable apparatus, the similar multimeter of profile.

Below Figure of description is further specified as follows: Fig. 1 is the contour structures synoptic diagram of the magnetometer of auto-range and digital zero setting; Fig. 2 is the survey magnetic probe structural representation of magnetometer shown in Figure 1; Fig. 3 is the circuit block diagram of magnetometer shown in Figure 1; Fig. 4 is the circuit theory diagrams of magnetometer shown in Figure 1.Among each figure: 1 is casing, and 2 is 31/2 LCD LCD, and 3 is zero-setting button, and 4 for surveying the magnetic probe socket, and 5 is magneto sensor Hall (Hall element), and 6 is copper pipe, and 7 for surveying the magnetic probe handle, and 8 is shielded cable.

Embodiment of the present utility model can be as follows: (1) presses shown in Figure 1, design, processing and manufacturing casing 1 and panel thereof.Can adopt aluminium alloy or other metal to make material, with general machine-tooled method processing and manufacturing casing and panel thereof; (2) make and press the described interconnected relationship assembling of top instructions by Design and Machining system shown in Figure 2 and survey magnetic probe; Maybe can arrive market and choose SH type series survey magnetic probe; (3) by shown in Figure 1, can choose DV-16100 type multidigit LCD 2; Can select for use can with survey the matching used survey magnetic probe of magnetic probe socket 4, and be installed on the machine shell panel by described mutual alignment of top instructions and annexation; (4) by draw PCB shown in Figure 4, and the screening components and parts carry out Installation and Debugging.Wherein: the optional LM324 type of U1 four-operational amplifier; The optional MC4070 type of U2 XOR gate; U3, U6, the optional MC14585 type 4 bit value comparers of U7; The optional MC4069 type of U4, U9 not gate integration member; U5 can select X9C104 type digital regulation resistance module for use; U8 can select AD7501 type multiway analog switch module for use; The optional ICL7106 type of U10 double integral A/D converter integration member; The optional MC4098 type of U11 trigger flip-flop integration member; The optional MC4001 type of U12 rejection gate integration member; (5) be loaded in the casing by the good circuit board of Installation and Debugging, and its appropriate section is installed and is connected with LCD LCD 2, zero-setting button 3, survey magnetic probe socket 4 respectively, and peg graft to go up and survey magnetic probe, just can finish the utility model preferably.

Claims (3)

1, a kind of by casing, zero-setting button, the auto-range that survey magnetic probe etc. constitutes and the magnetometer of digital zero setting, it is characterized in that: it is by casing (1), 31/2 LCD LCD (2), zero-setting button (3), survey magnetic probe socket (4), survey magnetic probe, the common binding of circuit board assembles, its mutual alignment and annexation are: circuit board is fixedly installed in the casing (1), survey the magnetic probe cover and insert in survey magnetic probe socket (4), 31/2 LCD LCD (2) is installed on the panel top of casing and is electrically connected mutually with corresponding A/D converter on the circuit board, zero-setting button (3) is installed on the middle and upper part of machine shell panel and is electrically connected mutually with circuit board respective digital zeroing circuit, survey magnetic probe socket (4) be installed on the machine shell panel bottom and with circuit board on corresponding programmable amplifier circuit be electrically connected mutually; Wherein: the survey Magnetic Sensor that the magnetometer circuit is made up of current source and magneto sensor, programmable amplifier, digital zero setting circuit, memory, comparison and latch auto-range circuit, A/D converter, LCD display and be electrically connected jointly and constitute, it is connected to each other to close and is: current source is electrically connected mutually by current source output line and magneto sensor and constitutes the survey Magnetic Sensor; Programmable amplifier respectively by survey Magnetic Sensor output signal line, digital zero setting circuit output signal line, memory, comparison and latch auto-range circuit control signal output line, program control signal output line respectively with survey Magnetic Sensor, digital zero setting circuit, memory, comparison and latch the auto-range circuit, A/D converter is electrically connected mutually, A/D converter respectively by the A/D converter output signal line respectively with LCD display and memory, comparison with latch the auto-range circuit and be electrically connected mutually.

2, by the described auto-range that constitutes by casing, zero-setting button, survey magnetic probe etc. of claim 1 and the magnetometer of digital zero setting, it is characterized in that described survey Magnetic Sensor is electrically connected jointly and is constituted by operational amplifier U1A, triode N1, resistance R 1, current regulating resistance device W2, magneto sensor Hall; Programmable amplifier is by operational amplifier integration member U1C, U1D, multiway analog switch U8, adjustable resistor W _2T, W _200mT, resistance R 2, R4, R8～R10 be electrically connected formation jointly; The digital zero setting circuit is electrically connected jointly and is constituted by trigger flip-flop integration member U11A, simulation memory circuit integration member U5, resistance R 3, resistance R 18, pushbutton switch S1, capacitor C 5; Memory, relatively and latch the auto-range circuit and be electrically connected jointly than integrated circuit U3, U6, U7 and ungated integrated circuit U4D by rejection gate integration member U12A, U12B, U12C, U12D, numeric ratio and constitute; A/D converter is connected and composed jointly by double integral A/D converter integration member U10, adjustable resistor W1, resistance R 11～R13, capacitor C 1～C4, electrochemical capacitor C6; LCD display is made of LCD MODULE.

3, by the described auto-range that constitutes by casing, zero-setting button, survey magnetic probe etc. of claim 1 and the magnetometer of digital zero setting, it is characterized in that described survey magnetic probe is by magneto sensor, be that Hall element (5), copper pipe (6), handle (7), shielded cable (8) connect and compose jointly, its interconnected relationship is: magneto sensor (5) connects with copper pipe (6), copper pipe (6) and handle (7) Joint, shielded cable (8) are electrically connected mutually with copper pipe (6) and survey magnetic probe socket respectively.

Images