CN203224209U

CN203224209U - Low temperature-drift multi-range strain acquisition circuit

Info

Publication number: CN203224209U
Application number: CN 201320194828
Authority: CN
Inventors: 王云山; 田方正; 穆军友; 王立强; 魏浩
Original assignee: XI'AN ZHONGFEI AVIATION TEST TECHNOLOGY DEVELOPMENT Co Ltd
Current assignee: XI'AN ZHONGFEI AVIATION TEST TECHNOLOGY DEVELOPMENT Co Ltd
Priority date: 2013-04-17
Filing date: 2013-04-17
Publication date: 2013-10-02
Anticipated expiration: 2023-04-17

Abstract

The utility model relates to a low-temperature drift multi-range strain acquisition circuit. According to existing strain acquisition circuits, positive and negative bridge voltage is mainly adopted to supply power, and voltage difference of strain electric bridge power supply is larger, and as a result, the power supply loss of the existing strain acquisition circuits is large; and the existing strain acquisition circuits are affected by temperature drift of analog devices, and the acquisition accuracy of the existing strain acquisition circuits can be influenced to different degrees. The low temperature-drift multi-range strain acquisition circuit includes a first-stage amplifier circuit, an analog filter circuit, an analog-to-digital conversion circuit, a sensor bridge voltage excitation output circuit and a sensor type control circuit. The low-temperature drift multi-range strain acquisition circuit is characterized in that an integrated signal conditioning circuit is arranged between the first-stage amplifier circuit and the analog filter circuit; the sensor bridge voltage excitation output circuit is connected with the integrated signal conditioning circuit; the sensor type control circuit is provided with an analog switch; and the sensor bridge voltage excitation output circuit comprises a single power supply amplifier. With the low-temperature drift multi-range strain acquisition circuit of the utility model adopted, not only can strain measurement range be increased, but also the power consumption of the strain acquisition circuit can be greatly reduced.

Description

A kind of low temperature floats multiple range strain acquirement circuit

Technical field

The utility model relates to a kind of strain acquirement circuit, especially relates to a kind of low temperature and floats multiple range strain acquirement circuit.

Background technology

The application of strain acquirement circuit is more extensive, and it is mainly used in the human body weighing, large-scale weighing system, large bridge structure monitoring, occasions such as aerospacecraft, aircraft, the collection of boats and ships strain parameter.Existing strain acquirement circuit adopts positive and negative bridge to press power supply, though its common mode inhibition wider range, the pressure reduction of strain bridge power supply is bigger, and therefore, its current supply loss is bigger; In addition, limited by the difference of various application scenarios, most strain acquirement circuit range design is more single, and is subjected to the temperature drift effects of analog device, and its acquisition precision has been subjected to influence in various degree.

Summary of the invention

Technical problem to be solved in the utility model provides a kind of a kind of low temperature that reduces the power consumption of circuit own and raising circuit acquisition precision and floats multiple range strain acquirement circuit.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of low temperature floats multiple range strain acquirement circuit, comprise first order amplifier circuit, analog filter circuit, analog to digital conversion circuit, sensor bridge is pressed the excitation output circuit, the sensor type control circuit, first input end, second input end and the 3rd input end, described analog converter circuit comprises analog converter, analog-digital conversion circuit as described comprises analog to digital converter, its special feature is: be provided with the integrated signal modulate circuit between described first order amplifier circuit and the analog filter circuit, described sensor bridge presses the excitation output circuit to be connected with the comprehensively regulating circuit, described sensor type control circuit is provided with analog switch, and described sensor bridge presses the excitation output circuit to comprise the single supply amplifier.

Described comprehensively regulating circuit comprises signal conditioner, and the model of this signal conditioner is MAX1452, and the model of described single supply amplifier is AD8531, and the model of described analog switch is ADG742.

The model of described analog filter is MAX7420, and the model of analog to digital converter is AD7694.

Compared with prior art, the beneficial effects of the utility model are:

1. be provided with the integrated signal modulate circuit in the utility model and realize two gain per stages amplification, adopt the MAX1452 signal conditioner in the comprehensively regulating circuit, this signal conditioner has 16 grades of programmable-gains, gain margin is 39～234 times, make this circuit guarantee to have increased the strain measurement range under the constant prerequisite of acquisition precision;

2. because signal conditioner has programmable-gain, the strain bridge sensor is connected with signal conditioner, and by on-off circuit whole strain bridge sensing circuit is controlled, make to the utlity model has full-bridge/half-bridge selection function able to programme;

3. the utility model comprehensively regulating circuit can realize that single supply provides bridge to press excitation to bridge sensor, greatly reduces the power consumption of strain acquirement circuit;

4. the resolution of analog to digital converter AD7694 of the present utility model is 16, and high sampling rate reaches 250KHz, makes that the inhibiting effect to temperature drift improves greatly, thereby has improved the acquisition precision of this circuit.

Description of drawings

Describe the utility model in detail below in conjunction with drawings and embodiments:

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

Fig. 2 is circuit diagram of the present utility model.

Among the figure: 1. first order amplifier circuit, 2. integrated signal modulate circuit, 3. sensor bridge is pressed excitation output circuit, 4. analog filter circuit, 5. analog to digital conversion circuit, 6. first input end, 7. second input end, 8. the 3rd input end, 9, sensor type control circuit, 10. strain bridge sensor.

Embodiment

A kind of low temperature floats multiple range strain acquirement circuit, comprise first order amplifier circuit 1, analog filter circuit 4, analog to digital conversion circuit 5, sensor bridge is pressed excitation output circuit 3, sensor type control circuit 9, strain bridge sensor 10, first amplifier circuit 1 is connected 6 with first input end, sensor bridge presses excitation output circuit 3 to be connected with second input end 7, sensor type control circuit 9 is connected with the 3rd input end 8, first input end 6, second input end 7 is connected with strain bridge sensor 10 respectively with the 3rd input end 8, be provided with integrated signal modulate circuit 2 between first order amplifier circuit 1 and analog filter circuit 4, sensor bridge presses excitation output circuit 3 to be connected with integrated signal modulate circuit 2.

Analog filter circuit 4 comprises analog converter, its model is MAX7420, analog to digital conversion circuit 5 comprises analog to digital converter, its model is AD7694, sensor bridge presses excitation output circuit 3 to comprise the single supply amplifier, its model is AD8531, and described sensor type control circuit 9 comprises analog switch, and its model is ADG742.

As shown in Figure 2, sensor bridge presses the excitation output circuit to be made up of U2 and C2; First order amplifier circuit is made up of U3, R3, C3 and C4; U4, R4, R5, R6 and C5 form the integrated signal modulate circuit jointly, and this circuit has been realized constant current source excitation and two kinds of functions of second level gain amplification, and analog filter circuit is made up of U5 and C6; Analog to digital conversion circuit is made up of U6; The sensor type control circuit is made up of U1, C1, R1 and R2; This circuit work power employing+5V.

Principle of work of the present utility model is: integrated signal modulate circuit 2 is pressed excitation output circuit 3 for sensor bridge programmable single supply excitation is provided, programmed range is 1.2V～4.5V, sensor bridge is pressed the single supply amplifier AD8531 in the excitation output circuit 3 to increase the one-level bridge and is pressed, and press excitation to be delivered to strain bridge sensor 10 by the 3rd input end 8 bridge, strain bridge sensor 10 switches strain bridge sensor 10 by the analog switch ADG742 of sensor type control circuit 9, realize strain bridge sensor 10 full-bridges/half-bridge function, when selecting full-bridge, analog switch ADG742 is in off-state, at this moment, the strain bridge connection adopts four-wire system, it is the bridge positive pressure, bridge is pressed negative, signal just, signal is negative; When selecting half-bridge, analog switch ADG742 is in on-state, and at this moment, the strain bridge connection adopts three-wire system, i.e. bridge positive pressure, and bridge is pressed negative, and signal is just; Strain bridge sensor 10 is transported to first order amplifier circuit 1 with simulating signal by first input end 6, the amplifier MAX4194 that adopts in the first order amplifier circuit 1 provides 11 times first order fixed gain to amplify, simulating signal is again by integrated signal modulate circuit 2, realized second level gain amplification, the amplifier MAX4194 that adopts in the first order amplifier circuit 1 provides 11 times first order fixed gain to amplify, MAX1452 signal conditioner in the comprehensively regulating circuit 2 has 16 grades of programmable-gains, gain margin is 39～234, the strain acquirement signal carries out filtering by analog filter MAX7420 after amplifying through two-stage again, analog filter MAX7420 is 5 rank low pass Butterworth switching capacity frequency overlapped-resistable filters, be 0.001Hz～30KHz by frequency, the resolution of analog to digital converter AD7694 is 16, high sampling rate reaches 250KHz, the work that analog to digital converter goes round and begins again according to the sampling rate of configuration.

The bridge of signal conditioner presses output consistent with the temperature drift of 5V supply voltage, therefore, the voltage reference of A/D is provided by the 5V supply voltage, greatly reduces the temperature drift of bridge pressure to the influence of acquisition precision, thereby has abandoned the way of traditional comparatively loaded down with trivial details temperature compensation.

The above only is preferred embodiments of the present utility model; protection domain of the present utility model is not limited with above-mentioned embodiment; as long as the equivalence that those of ordinary skills do according to the utility model institute disclosure is modified or changed, all should include in the protection domain of putting down in writing in claims.

Claims

1. a low temperature floats multiple range strain acquirement circuit, comprise first order amplifier circuit (1), analog filter circuit (4), analog to digital conversion circuit (5), sensor bridge is pressed excitation output circuit (3), sensor type control circuit (9), first input end (6), second input end (7) and the 3rd input end (8), described analog filter circuit (4) comprises analog converter, analog-digital conversion circuit as described (5) comprises analog to digital converter, it is characterized in that: be provided with integrated signal modulate circuit (2) between described first order amplifier circuit (1) and the analog filter circuit (4), described sensor bridge presses excitation output circuit (3) to be connected with comprehensively regulating circuit (2), described sensor type control circuit (9) is provided with analog switch, and described sensor bridge presses excitation output circuit (3) to comprise the single supply amplifier.

2. a kind of low temperature according to claim 1 floats multiple range strain acquirement circuit, it is characterized in that: described comprehensively regulating circuit (2) comprises signal conditioner, the model of this signal conditioner is MAX1452, the model of described single supply amplifier is AD8531, and the model of described analog switch is ADG742.

3. a kind of low temperature according to claim 1 floats multiple range strain acquirement circuit, it is characterized in that: the model of described analog filter is MAX7420, and the model of analog to digital converter is AD7694.