CN202126492U - Digital fluxgraph - Google Patents

Abstract

The utility model discloses a digital fluxgraph which comprises an excitation coil and a measuring coil, wherein the excitation coil is connected to an excitation circuit; the measuring coil is connected to a signal processing circuit; the excitation circuit comprises a digital oscillating circuit and a frequency-selection amplifying circuit which are connected to the excitation coil after being sequentially and mutually connected in series; the signal processing circuit comprises a signal processing frequency-selection amplifying circuit, a phase sensitive detection circuit, a singlechip and an output interface which are sequentially connected in series; the input end of the signal processing frequency-selection amplifying circuit is connected with the measuring coil; and the phase sensitive detection circuit is also connected to the digital oscillating circuit. The utility model has the technical effects that the digital circuit is adopted to replace the analog circuit of the original sensor, so as to effectively improve the temperature performance and the linearity of the sensor; the digital fluxgraph is high in reliability and detection accuracy, compact in structure, small in volume, light in weight, good in vibration strength and high in detection stability, and has little power consumption.

Description

A kind of digital fluxgraph

Technical field

The utility model relates to a kind of fluxgraph, particularly a kind of digital fluxgraph.

Background technology

The magnetic measurement sensor can be applicable to geological exploration, industrial flaw detection, vehicle control, searches weapon and many fields such as aircraft, satellite, ships and automobile navigation.And reluctance type (AMR) Magnetic Measurement Technology can construction magnetic measurement sensor technology, but is characterized in its insufficient sensitivity, poor linearity and the weak magnetic sensor that can not form premium properties is measured technology of preparing.

Fluxgate sensor is a kind of sensor that is used to measure Weak magentic-field.Its measurement range is 0～10-12T, and the energy measurement magnetic-field component.Be specially adapted to the measurement in the system of high-speed motion, in the magnetic field measuring device of many types, fluxgate sensor is best a kind of of combination property.The output of fluxgate magnetic core mainly be the excitation second harmonic, need carry out signal condition, it be transformed into by the linear d. c. voltage signal of measuring magnetic field.

The conventional fluxgate sensor mainly adopts mimic channel to handle, and is that circuit receives Influence of Temperature bigger but adopt the outstanding problem of mimic channel.Under open loop approach, very big with variation of temperature by the magnetic permeability unshakable in one's determination of fluxgate coil, the change of sensitivity of fluxgate sensor is also very big.Fluxgate coil body and signal condition temperature drift, zero drift partly all has obvious defects.And preparation technology is numerous and diverse, and consistance is poor, and the quality of production is difficult to guarantee that maintainability is also relatively poor.

Along with computing machine and fast development of information technology, digitizing is its development trend.The ratio of precision that the digitizing flux-gate magnetometer has the range ability broad, survey magnetic is higher, compact conformation, volume is little, in light weight, power consumption is little, vibration strength is good, stability is high, be suitable for high-speed motion use and ability continuous automatic measurement.

The utility model content

Existing mimic channel fluxgate sensor stability is not enough, preparation technology is numerous and diverse, consistance is poor in order to solve, the quality of production is difficult to guarantee, the technical matters of maintainable difference, and the utility model provides that a kind of reliability is high, accuracy of detection is high, compact conformation, volume is little, in light weight, power consumption is little, vibration strength is good, detect the high digital fluxgraph of stability.

In order to reach above-mentioned technical purpose; The technical scheme of the utility model is that a kind of digital fluxgraph comprises fluxgate coil, exciting circuit and signal processing circuit; Described fluxgate coil comprises drive coil and measures coil; Described drive coil is connected to exciting circuit, and described measurement coil is connected to signal processing circuit, it is characterized in that; Described exciting circuit comprises digital oscillatory circuit and excitatory selective frequency amplifier circuit; Be connected to magnetizing coil after described digital oscillatory circuit and selective frequency amplifier circuit are connected successively, described signal processing circuit comprises signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface, and described signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface are connected successively; The input end of signal Processing selective frequency amplifier circuit connects the measurement coil and is connected to the measurement coil, and described phase-sensitive detection circuit also is connected to digital oscillatory circuit.

Described a kind of digital fluxgraph, described output interface are RS-232 interface and 485 serial line interfaces.

Described a kind of digital fluxgraph, described single-chip microcomputer is the C8051F020 single-chip microcomputer.

Described a kind of digital fluxgraph, described digital oscillatory circuit adopts CD4060 as oscillator.

Described a kind of digital fluxgraph, described phase-sensitive detection circuit adopt CD4052 as the detection chip.

The technique effect of the utility model is; Adopt digital circuit to replace the mimic channel of original sensor; Improved the temperature performance and the linearity of sensor effectively, and reliability is high, accuracy of detection is high, compact conformation, volume is little, in light weight, power consumption is little, vibration strength is good, it is high to detect stability.

Below in conjunction with accompanying drawing the utility model is described further.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the process flow diagram of the utility model processing signals.

Embodiment

Referring to Fig. 1, Fig. 2; The utility model comprises fluxgate coil, exciting circuit and signal processing circuit; The fluxgate coil comprises drive coil and measures coil that drive coil is connected to exciting circuit, measures coil and is connected to signal processing circuit; Exciting circuit comprises digital oscillator and excitatory selective frequency amplifier circuit; Be connected to magnetizing coil after numeral oscillatory circuit and selective frequency amplifier circuit are connected successively, signal processing circuit comprises signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface, and signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface are connected successively; The input end of signal Processing selective frequency amplifier circuit connects the measurement coil and is connected to the measurement coil, and phase-sensitive detection circuit also is connected to digital oscillatory circuit.

Two fluxgates unshakable in one's determination are by 2 identical singlecore fluxgates of parameter the primary coil reversal connection to be formed.Feed for the primary coil of two fluxgates unshakable in one's determination to be enough to when making saturated ac-excited electric current unshakable in one's determination, because by the influence of measuring magnetic field, the magnetic field in 2 coils is unequal.According to the characteristic of iron core, the magnetic induction density that they produce in corresponding secondary coil is also different.2 secondary coils along connecing, can be obtained the output voltage of two fluxgates unshakable in one's determination.After this signal carried out phase depending on rectification and filtering, just can obtain with by the relevant VD of measuring magnetic field.

Exciting circuit adopts the inner oscillator of CD4060, and external high-accuracy capacitor and resistance constitute.Basic frequency is 40KHz, carries out small-sized frequency synthesis by CD4060 simultaneously and handles, and produces base step 8 frequency division 5KHz and 16 frequency division 2.5KHz frequently and supplies phase-sensitive detection circuit to use.Wherein phase-sensitive detection circuit adopts CD4052 as the detection chip.

Influence zero point and sensitivity that conventional fluxgate sensor measurement accuracy factors is a sensor.Generally speaking, zero point and sensitivity meeting change along with variation of temperature, when changing greatly, must carry out temperature compensation.If fluxgate output signal is sampled with A/D, then, adopt algorithm that sampled signal is carried out phase depending on rectification, just can address this problem.

The utility model also can be ordered to host computer request parameter by single-chip microcomputer after can sending order to single-chip microcomputer through serial ports.Single-chip microcomputer begins the signal and the scene temperature signal of fluxgate magnetic core output are sampled according to the autonomous A/D that starts of order.Data after the sampling are kept in the RAM of single-chip microcomputer; Can carry out algorithm process one time; This time handle and have independence; Be the distributed signal Processing that autonomous sensor signal conditioning partly carries out, and be to float and the Nonlinear Processing technology, be uploaded to upper PC through serial ports again with the identical a kind of temperature in signal condition part scene temperature field.These data can be passed through secondary treating in PC, obtain reflecting by the digital quantity of measuring magnetic field size supplying to show or control.Single-chip microcomputer adopts and mixes the main control chip of SOC(system on a chip) C8051F020 as Acquisition Circuit.This single-chip microcomputer has 2 high-precision high-speed A/D that are integrated on the sheet.The control able to programme of the switching rate of A/D, maximum can reach 1M/s.Single-chip microcomputer has internal reference.Except the internal data memory of 256 bytes, also have external data storage space (XRAM) on the sheet of 4k.Support non-intrusion type, on-line system debugging at full speed.Have built-in temperature sensor, its precision can be measured fluxgraph work on the spot temperature.

The fundamental frequency of signal is 3kHz, and SF is 150kHz.To input signal amplify in right amount with centered level adjustment after, just can directly insert the input end of one road A/D and sample.RS-232 bus standard interface is adopted in the serial communication of single-chip microcomputer and PC, possesses 485 serial ports teletransmission abilities simultaneously.

To input signal amplify in right amount with centered level adjustment maybe be to the signal DC component that superposes.In order to address this problem, the formula of stating after the employing (3) is handled sampled data.If the sequence that sampling obtains is x (n) (n is a sampled point, and p counts for what sample altogether), try to achieve the average of being had a few, deduct average to x (n), obtain x (n), shown in (1).

$X\left(n\right)=x\left(n\right)-\underset{i=1}{\overset{p}{\mathrm{\Σ}}}x\left(i\right)/p---\left(1\right)$

Then, carry out phase depending on rectification.The effect of the fluxgate treatment circuit of the effect before introduction of this part is basic identical.All be in the preceding half period of reference signal signal to be carried out homophase to amplify, in the back half period of reference signal signal carried out anti-phase and amplify.Difference is: the signal that the front will be handled is a simulating signal, and the signal that will handle now is a digital signal.Phase reference signal R (n) that phase depending on rectification is used and excitation are from same oscillator.Signal after the phase depending on rectification is H (n), shown in (2).

H(n)＝X(n)·R(n) (2)

Data after the phase depending on rectification must the elimination high fdrequency component, just can obtain reflecting the DC quantity of tested magnitude of field intensity.Here, adopt the way of P some sum-average arithmetic.This method not only can realize the filtering to signal, can also eliminate the error in the data acquisition.In order to guarantee to export any time the unanimity of digital quantity, p should be chosen as the integral multiple that periodic sampling is counted.Shown in (3), the d. c. voltage signal of Y (n) for finally obtaining

$Y\left(n\right)=\underset{n=1}{\overset{p}{\mathrm{\Σ}}}H\left(n\right)/p---\left(3\right)$ 。

Claims (5)

1. digital fluxgraph; Comprise fluxgate coil, exciting circuit and signal processing circuit; Described fluxgate coil comprises drive coil and measures coil; Described drive coil is connected to exciting circuit, and described measurement coil is connected to signal processing circuit, it is characterized in that; Described exciting circuit comprises digital oscillatory circuit and excitatory selective frequency amplifier circuit; Be connected to magnetizing coil after described digital oscillatory circuit and selective frequency amplifier circuit are connected successively, described signal processing circuit comprises signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface, and described signal Processing selective frequency amplifier circuit, phase-sensitive detection circuit, single-chip microcomputer, output interface are connected successively; The input end of signal Processing selective frequency amplifier circuit connects the measurement coil and is connected to the measurement coil, and described phase-sensitive detection circuit also is connected to digital oscillatory circuit.

2. a kind of digital fluxgraph according to claim 1 is characterized in that, described output interface is RS-232 interface and 485 serial line interfaces.

3. a kind of digital fluxgraph according to claim 1 is characterized in that described single-chip microcomputer is the C8051F020 single-chip microcomputer.

4. a kind of digital fluxgraph according to claim 1 is characterized in that, described digital oscillatory circuit adopts CD4060 as oscillator.

5. a kind of digital fluxgraph according to claim 1 is characterized in that, described phase-sensitive detection circuit adopts CD4052 as the detection chip.

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