Temperature measurement circuit of relative gravimeter and relative gravimeter

Abstract

The present invention discloses a temperature measurement circuit for a relative gravimeter and a relative gravimeter. The temperature measurement circuit of the relative gravimeter includes: a reference voltage module, a binary commutation constant current module, a voltage follower module, and a voltage processing module; the binary commutation constant current module includes a binary commutation driving unit and a constant current unit; the reference voltage module is used to provide a reference voltage for the constant current unit and the voltage processing module, the constant current unit is used to generate a constant current according to the reference voltage; the voltage processing module is used to control the alternating change of the flow direction of the constant current flowing through the binary commutation driving unit, and the voltage follower module is used to collect the voltage data at the driving end of the binary commutation driving unit; the voltage processing module is used to eliminate the error of the voltage data and obtain the temperature data according to the voltage data after eliminating the error. The circuit structure of this case is simple, and the error generated in the process of collecting and transmitting the voltage data can be reduced under the collaborative temperature measurement of each module, thereby improving the temperature measurement accuracy and temperature measurement efficiency.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of temperature measurement, and in particular, to a temperature measurement circuit and a relative gravimeter for a relative gravimeter. Background Art

[0002] In the high-precision temperature control technology field of spring gravimeters, high-precision temperature measurement needs to be achieved. At present, the technical principles of temperature measurement for spring gravimeters mainly include the pointer ohmmeter principle, the Wheatstone bridge circuit principle, and the super resistance thermometer principle, etc. Among them, both the pointer ohmmeter principle and the Wheatstone bridge circuit principle can achieve temperature measurement with a certain accuracy, but there are problems such as the temperature measurement accuracy not meeting the standard, the influence of non-linear factors on temperature measurement, and the complexity of the temperature measurement circuit. The super resistance thermometer principle can achieve relatively ideal temperature measurement accuracy, but the circuit using the super resistance thermometer principle to achieve temperature measurement generally adopts a dual modulus conversion mode, which makes the circuit using the super resistance thermometer principle to achieve temperature measurement relatively complex, and thus the speed of temperature measurement is average, and the measurement efficiency cannot be effectively improved. Summary of the Invention

[0003] The embodiments of the present invention provide a temperature measurement circuit and a relative gravimeter for a relative gravimeter to improve the temperature measurement accuracy and temperature measurement efficiency.

[0004] In a first aspect, the embodiments of the present invention provide a temperature measurement circuit for a relative gravimeter, which includes: a reference voltage module, a binary commutation constant current module, a voltage follower module, and a voltage processing module;

[0005] The binary commutation constant current module includes a binary commutation driving unit and a constant current unit;

[0006] The reference voltage module is respectively connected to the constant current unit and the voltage processing module. The reference voltage module is used to provide a reference voltage for the constant current unit and the voltage processing module, and the constant current unit is used to generate a constant current according to the reference voltage;

[0007] The binary commutation driving unit is respectively connected to the constant current unit, the voltage follower module, and the voltage processing module. The voltage processing module is used to control the flow direction of the constant current flowing through the binary commutation driving unit to alternate, and the voltage follower module is used to collect the voltage data at the driving end of the binary commutation driving unit;

[0008] The voltage follower module is connected to the voltage processing module. The voltage processing module is used to eliminate the error of the voltage data and obtain temperature data according to the voltage data after eliminating the error.

[0009] Optionally, the binary commutation driving unit includes a first analog switch, a second analog switch, a third analog switch, a fourth analog switch, and a thermistor;

[0010] The binary commutation driving unit includes a first driving end, a second driving end, an input end, and an output end;

[0011] The constant current unit includes a first input end and an output end;

[0012] The first ends of the first analog switch and the second analog switch are connected and serve as the output end of the binary commutation driving unit to be connected to the first input end of the constant current unit; the first ends of the third analog switch and the fourth analog switch are connected and serve as the input end of the binary commutation driving unit to be connected to the output end of the constant current unit; the second ends of the first analog switch and the third analog switch are both connected to the first end of the thermistor and serve as the first driving end of the binary commutation driving unit; the second ends of the second analog switch and the fourth analog switch are both connected to the second end of the thermistor and serve as the second driving end of the binary commutation driving unit;

[0013] The first analog switch, the second analog switch, the third analog switch, and the fourth analog switch are all connected to the voltage processing module, and the voltage processing module is used to control the on / off of the first analog switch, the second analog switch, the third analog switch, and the fourth analog switch.

[0014] Optionally, the voltage follower module includes a first input end and a second input end;

[0015] The first input end of the voltage follower module is connected to the first driving end of the binary commutation driving unit, and the first input end of the voltage follower module is used to collect the voltage data of the first end of the thermistor;

[0016] The second input end of the voltage follower module is connected to the second driving end of the binary commutation driving unit, and the second input end of the voltage follower module is used to collect the voltage data of the second end of the thermistor.

[0017] Optionally, the constant current unit includes a first operational amplifier and a third resistor;

[0018] The first end of the first operational amplifier is connected to the reference voltage module, the second end of the first operational amplifier, the first end of the third resistor, and the output end of the binary commutation driving unit are connected, the second end of the third resistor is grounded, and the third end of the first operational amplifier is connected to the input end of the binary commutation driving unit.

[0019] Optionally, the reference voltage module includes a first voltage output terminal and a second voltage output terminal; the first voltage output terminal of the reference voltage module is used to output a first reference voltage, and the second voltage output terminal of the reference voltage module is used to output a second reference voltage;

[0020] The reference voltage module includes a reference voltage chip, a first resistor, a second resistor, and a capacitor;

[0021] The input terminal of the reference voltage chip is connected to an external power supply; the output terminal of the reference voltage chip, the first terminal of the capacitor, and the first terminal of the first resistor are connected and serve as the first voltage output terminal of the reference voltage module; the second terminal of the first resistor is connected to the second terminal of the second resistor and serves as the second voltage output terminal of the reference voltage module; the second terminal of the capacitor is grounded together with the second terminal of the second resistor.

[0022] Optionally, the voltage processing module includes a divider, a multiplier, an analog-to-digital conversion unit, and a data processing unit;

[0023] The divider is respectively connected to the voltage follower module and the second voltage output terminal of the reference voltage module, and the divider is used to perform a division operation on the voltage data according to the second reference voltage to obtain first voltage processing data;

[0024] The multiplier is respectively connected to the divider and the first voltage output terminal of the reference voltage module, and the multiplier is used to perform a multiplication operation on the first voltage processing data according to the first reference voltage to obtain second voltage processing data;

[0025] The analog-to-digital conversion unit is respectively connected to the multiplier and the first voltage output terminal of the reference voltage module, and the analog-to-digital conversion unit is used to perform analog-to-digital conversion on the second voltage processing data according to the first reference voltage to obtain third voltage processing data;

[0026] The data processing unit is connected to the analog-to-digital conversion unit. The data processing unit is used to eliminate the error of the third voltage processing data to obtain fourth voltage processing data, and fit the fourth voltage processing data with the temperature-voltage relationship curve to obtain the temperature data.

[0027] Optionally, the divider includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, a first output terminal, and a second output terminal;

[0028] The voltage follower module further includes a first output terminal and a second output terminal; a first input terminal of the divider is connected to the first output terminal of the voltage follower module, a second input terminal of the divider is connected to the second output terminal of the voltage follower module, a third input terminal of the divider is connected to a second voltage output terminal of the reference voltage module, and a fourth input terminal and a second output terminal of the divider are grounded;

[0029] The divider is configured to process data input through the first input terminal, the second input terminal, the third input terminal, the fourth input terminal, and the second output terminal thereof, and output first voltage processed data at a first output terminal.

[0030] Optionally, the multiplier includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, a first output terminal, and a second output terminal;

[0031] The first input terminal of the multiplier is connected to the divider, the second input terminal, the fourth input terminal, and the second output terminal of the multiplier are grounded, and the third input terminal of the multiplier is connected to a first voltage output terminal of the reference voltage module;

[0032] The multiplier is configured to process data input through the first input terminal, the second input terminal, the third input terminal, the fourth input terminal, and the second output terminal thereof, and output second voltage processed data at a first output terminal.

[0033] Optionally, the data processing unit includes an input terminal, a first output terminal, and a second output terminal;

[0034] The first output terminal of the data processing unit is connected to the analog-to-digital conversion unit, the second output terminal of the data processing unit is connected to the binary commutation driving unit, and the data processing unit is configured to simultaneously transmit a pulse signal generated thereby to the analog-to-digital conversion unit and the binary commutation driving unit through the first output terminal and the second output terminal thereof;

[0035] The input terminal of the data processing unit is connected to the analog-to-digital conversion unit, and the data processing unit is configured to receive the third voltage processed data.

[0036] In a second aspect, an embodiment of the present invention further provides a relative gravimeter, which includes the temperature measurement circuit of the relative gravimeter according to any embodiment of the present invention.

[0037] The advantages and positive effects of the present invention are:

[0038] The temperature measurement circuit of the relative gravimeter composed of a reference voltage module, a binary commutation constant current module, a voltage follower module, and a voltage processing module has a simple structure and can quickly achieve temperature measurement, thereby improving the efficiency of temperature measurement. In addition, the reference voltage module can provide a stable and accurate reference voltage for other modules according to the specific requirements of the temperature measurement circuit of the relative gravimeter. Thus, the constant current unit included in the binary commutation constant current module can generate a constant current with a stable magnitude, and the binary commutation driving unit included in the binary commutation constant current module can, under the control of the voltage processing module, make the direction of the constant current flowing through itself alternate, thereby eliminating the thermoelectric potential generated when the constant current flows through the binary commutation driving unit. The voltage processing module processes the voltage data collected by the voltage follower module according to the reference voltage, which can reduce the error generated by the circuit characteristics during the acquisition and transmission of the voltage data, and thus can determine accurate temperature data based on the voltage data after eliminating the error. It can be seen that the temperature measurement circuit of the relative gravimeter in this solution can improve the accuracy of temperature measurement by the coordinated cooperation of the reference voltage module, the binary commutation constant current module, the voltage follower module, and the voltage processing module. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0040] Figure 1 FIG. is a schematic structural diagram of a temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0041] Figure 2 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0042] Figure 3 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0043] Figure 4 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0044] Figure 5 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0045] Figure 6 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention;

[0046] Figure 7Schematic diagram of the temperature measurement circuit of another relative gravimeter provided by an embodiment of the present invention;

[0047] Figure 8 Schematic diagram of the temperature measurement circuit of another relative gravimeter provided by an embodiment of the present invention;

[0048] Figure 9 Ideal constant current diagram output by a constant current unit provided by an embodiment of the present invention;

[0049] Figure 10 Actual constant current diagram output by a constant current unit provided by an embodiment of the present invention;

[0050] Figure 11 Schematic diagram of the structure of a relative gravimeter provided by an embodiment of the present invention. Detailed implementation manners

[0051] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 1 Schematic diagram of the temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention, as Figure 1 shown, the temperature measurement circuit of the relative gravimeter includes: a reference voltage module 110, a binary commutation constant current module 120, a voltage follower module 130, and a voltage processing module 140; the binary commutation constant current module 120 includes a binary commutation driving unit 121 and a constant current unit 122;

[0054] The reference voltage module 110 is respectively connected to the constant current unit 122 and the voltage processing module 140. The reference voltage module 110 is used to provide a reference voltage for the constant current unit 122 and the voltage processing module 140. The constant current unit 122 is used to generate a constant current according to the reference voltage. The binary commutation driving unit 121 is respectively connected to the constant current unit 122, the voltage follower module 130, and the voltage processing module 140. The voltage processing module 140 is used to control the flow direction of the constant current flowing through the binary commutation driving unit 121 to alternately change. The voltage follower module 130 is used to collect the voltage data at the driving end of the binary commutation driving unit 121. The voltage follower module 130 is connected to the voltage processing module 140. The voltage processing module 140 is used to eliminate the error of the voltage data and obtain the temperature data according to the voltage data after eliminating the error.

[0055] Specifically, the reference voltage module 110 has the characteristics of high precision, good stability, and small temperature drift. The reference voltage module 110 can provide a stable and accurate reference voltage for other modules according to the specific requirements of the temperature measurement circuit of the relative gravimeter, which can improve the temperature measurement accuracy of the temperature measurement circuit of the relative gravimeter to a certain extent.

[0056] The binary commutation constant current module 120 can continuously generate a constant current with an alternating flow direction under the control of the voltage processing module 140, thereby eliminating the thermoelectric potential generated by the binary commutation constant current module 120, that is, eliminating the influence of the thermoelectric potential in the temperature measurement circuit of the relative gravimeter on the temperature measurement, so as to improve the temperature measurement accuracy of the temperature measurement circuit of the relative gravimeter to a certain extent. Among them, the constant current unit 122 included in the binary commutation constant current module 120 can generate a constant current with a stable magnitude, and the binary commutation driving unit 121 included in the binary commutation constant current module 120 can, under the control of the voltage processing module 140, make the flow direction of the constant current flowing through itself alternate, thereby eliminating the thermoelectric potential generated by the constant current flowing through the binary commutation driving unit 121.

[0057] The voltage follower module 130 has the characteristics of small data transmission error and small input bias current. Therefore, the voltage follower module 130 can accurately collect the voltage data at the driving end of the binary commutation driving unit 121 and accurately output the collected voltage data to the voltage processing module 140.

[0058] The voltage processing module 140 mainly includes three functions: 1) Process the voltage data collected by the voltage follower module 130 according to the reference voltage to reduce the error generated by the influence of the circuit characteristics during the acquisition and transmission of the voltage data. 2) Control the flow direction of the constant current flowing through the binary commutation driving unit 121 to alternately change, so as to further reduce the influence of the thermoelectric potential generated by the binary commutation driving unit 121 itself on the voltage data during the acquisition process. 3) Accurately determine the temperature data according to the processed voltage data.

[0059] The specific working process of the temperature measurement circuit of the relative gravimeter is as follows: The reference voltage generated by the reference voltage module 110 is output to the constant current unit 122. The constant current unit 122 generates a constant current according to the reference voltage. At the same time, the voltage processing module 140 controls the flow direction of the constant current flowing through the binary commutation constant current module 120 to alternate. The voltage follower module 130 collects the voltage data at the driving end of the binary commutation driving unit 121 during the process of the constant current flowing through the binary commutation constant current module 120, and accurately outputs the collected voltage data to the voltage processing module 140. After receiving the voltage data collected by the voltage follower module 130, the voltage processing module 140 processes the voltage data to reduce the error generated by the circuit characteristics during the acquisition and transmission of the voltage data, and determines the temperature data according to the voltage data after eliminating the error.

[0060] In the embodiment of the present invention, the temperature measurement circuit of the relative gravimeter composed of the reference voltage module 110, the binary commutation constant current module 120, the voltage follower module 130, and the voltage processing module 140 has a simple structure and can quickly realize temperature measurement, thereby improving the efficiency of temperature measurement. In addition, the reference voltage module 110 can provide a stable and accurate reference voltage for other modules according to the specific requirements of the temperature measurement circuit of the relative gravimeter. Thus, the constant current unit 122 included in the binary commutation constant current module 120 can generate a constant current with a stable magnitude, and the binary commutation driving unit 121 included in the binary commutation constant current module 120 can, under the control of the voltage processing module 140, make the flow direction of the constant current flowing through itself alternate, thereby eliminating the thermoelectric potential generated when the constant current flows through the binary commutation driving unit 121. The voltage processing module 140 processes the voltage data collected by the voltage follower module 130 according to the reference voltage, which can reduce the error generated by the circuit characteristics during the acquisition and transmission of the voltage data, and thus can determine the temperature data according to the voltage data after eliminating the error. It can be seen that the temperature measurement circuit of the relative gravimeter in this solution can improve the accuracy of temperature measurement by the collaborative operation of the reference voltage module 110, the binary commutation constant current module 120, the voltage follower module 130, and the voltage processing module 140.

[0061] Figure 2 As shown in the structural schematic diagram of another temperature measurement circuit of the relative gravimeter provided by the embodiment of the present invention, as Figure 2 shown, the binary commutation driving unit 121 includes a first analog switch S1, a second analog switch S2, a third analog switch S3, a fourth analog switch S4, and a thermistor Rt; the binary commutation driving unit 121 includes a first driving end A1, a second driving end A2, an input end A3, and an output end A4; the constant current unit 122 includes a first input end B1 and an output end B2;

[0062] The first terminal of the first analog switch S1 and the first terminal of the second analog switch S2 are connected and serve as the output terminal A4 of the binary commutation driving unit 121 to be connected to the first input terminal B1 of the constant current unit 122; the first terminal of the third analog switch S3 and the first terminal of the fourth analog switch S4 are connected and serve as the input terminal A3 of the binary commutation driving unit 121 to be connected to the output terminal B2 of the constant current unit 122; the second terminal of the first analog switch S1 and the second terminal of the third analog switch S3 are both connected to the first terminal of the thermistor Rt and serve as the first driving terminal A1 of the binary commutation driving unit 121; the second terminal of the second analog switch S2 and the second terminal of the fourth analog switch S4 are both connected to the second terminal of the thermistor Rt and serve as the second driving terminal A2 of the binary commutation driving unit 121;

[0063] The first analog switch S1, the second analog switch S2, the third analog switch S3, and the fourth analog switch S4 are all connected to the voltage processing module 140, and the voltage processing module 140 is used to control the on and off of the first analog switch S1, the second analog switch S2, the third analog switch S3, and the fourth analog switch S4.

[0064] Among them, the thermistor Rt is a sensor resistor whose resistance value changes with the change of temperature. The thermistor Rt has the characteristics of high sensitivity, wide operating temperature range, small volume, and good stability. Preferably, the thermistor Rt can adopt a 44008 type thermistor.

[0065] Specifically, the constant current generated by the constant current unit 122 can drive the thermistor Rt to work. The voltage processing module 140 can control the on and off of the first analog switch S1, the second analog switch S2, the third analog switch S3, and the fourth analog switch S4 to control the flow direction of the constant current flowing through the binary commutation constant current module 120 to alternate. For example, when the voltage processing module 140 controls the first analog switch S1 and the fourth analog switch S4 to be closed and the second analog switch S2 and the third analog switch S3 to be open, the constant current flows from the second driving terminal A2 of the binary commutation driving unit 121 to the first driving terminal A1 of the binary commutation driving unit 121, that is, from the second terminal of the thermistor Rt to the first terminal of the thermistor Rt. When the voltage processing module 140 controls the first analog switch S1 and the fourth analog switch S4 to be open and the second analog switch S2 and the third analog switch S3 to be closed, the constant current flows from the first driving terminal A1 of the binary commutation driving unit 121 to the second driving terminal A2 of the binary commutation driving unit 121, that is, from the first terminal of the thermistor Rt to the second terminal of the thermistor Rt.

[0066] It should be noted that: the voltage processing module 140 controls the on / off of the first analog switch S1, the second analog switch S2, the third analog switch S3, and the fourth analog switch S4, and the signal change speed is fast, which can make the constant current error offset of different flowing directions through the thermistor Rt basically equal.

[0067] In this solution, the temperature data is finally confirmed by collecting the voltage data at both ends of the thermistor Rt. Since the flowing direction of the constant current through the thermistor Rt alternates during the process of collecting the voltage data at both ends of the thermistor Rt, the influence of the thermoelectric potential generated when the constant current flows through the thermistor Rt on the voltage data at both ends of the thermistor Rt can be eliminated, thereby improving the temperature measurement accuracy of the temperature measurement circuit of the relative gravimeter to a certain extent.

[0068] Based on the above embodiments, optionally, continue to refer to Figure 2 , the voltage follower module 130 includes a first input terminal C1 and a second input terminal C2; the first input terminal C1 of the voltage follower module 130 is connected to the first driving terminal A1 of the binary commutation driving unit 121, and the first input terminal C1 of the voltage follower module 130 is used to collect the voltage data at the first end of the thermistor Rt; the second input terminal C2 of the voltage follower module 130 is connected to the second driving terminal A2 of the binary commutation driving unit 121, and the second input terminal C2 of the voltage follower module 130 is used to collect the voltage data at the second end of the thermistor Rt.

[0069] Among them, the voltage follower module 130 has the characteristics of small data transmission error and small input bias current. Therefore, the voltage follower module 130 can accurately collect the voltage data at the first end of the thermistor Rt through the first input terminal C1, and the voltage follower module 130 can accurately collect the voltage data at the second end of the thermistor Rt through the second input terminal C2.

[0070] Exemplarily, the voltage follower module 130 includes a precision operational amplifier of model ADA4528-2. Figure 3 This is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention. Figure 3 In , the first end of the precision operational amplifier 131 of model ADA4528-2 is used as the first input terminal C1 of the voltage follower module 130, and the second end of the precision operational amplifier 131 of model ADA4528-2 is used as the second input terminal C2 of the voltage follower module 130. The extremely low offset voltage of the precision operational amplifier 131 of model ADA4528-2 is less than or equal to 2.5 μV, and the input bias current is less than or equal to 400 pA. It can be seen that the current flowing into the precision operational amplifier 131 through the thermistor Rt is extremely small, and the voltage error transmitted by the precision operational amplifier 131 is extremely low, thereby improving the temperature measurement accuracy of the temperature measurement circuit of the relative gravimeter to a certain extent.

[0071] Based on the above embodiments, optionally, Figure 4 FIG. 4 is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention. As Figure 4 shown, the reference voltage module 110 includes a first voltage output terminal D1 and a second voltage output terminal D2; the first voltage output terminal D1 of the reference voltage module 110 is used to output a first reference voltage, and the second voltage output terminal D2 of the reference voltage module 110 is used to output a second reference voltage;

[0072] The reference voltage module 110 includes a reference voltage chip 111, a first resistor R1, a second resistor R2, and a capacitor C; the input terminal of the reference voltage chip 111 is connected to an external power supply 200; the output terminal of the reference voltage chip 111, the first terminal of the capacitor C, and the first terminal of the first resistor R1 are connected and serve as the first voltage output terminal D1 of the reference voltage module 110; the second terminal of the first resistor R1 is connected to the second terminal of the second resistor R2 and serves as the second voltage output terminal D2 of the reference voltage module 110; the second terminal of the capacitor C is grounded together with the second terminal of the second resistor R2.

[0073] Wherein, the constant current unit 122 further includes a second input terminal B3, and the second voltage output terminal D2 of the reference voltage module 110 is connected to the second input terminal B3 of the constant current unit 122. The output terminal of the reference voltage chip 111, the first terminal of the capacitor C, the first terminal of the first resistor R1, and the voltage processing module 140 are connected, and the second terminal of the first resistor R1, the second terminal of the second resistor R2, and the second input terminal of the constant current unit 122 are connected.

[0074] Based on the above embodiments, optionally, the reference voltage chip 111 includes a precision voltage reference chip of model LTC6657BRZ-4.096V, the first resistor R1 includes a first precision metal thin film resistor, and the second resistor R2 includes a second precision metal thin film resistor. Wherein, the precision error of both the first precision metal thin film resistor and the second precision metal thin film resistor is less than or equal to 0.1%, and the resistance values of the first precision metal thin film resistor and the second precision metal thin film resistor are equal and the resistance value range is 1KΩ - 10KΩ.

[0075] Wherein, the precision voltage reference chip of model LTC6657BRZ-4.096V can generate a high-precision 4.096V reference voltage (the first reference voltage), and the first precision metal thin film resistor and the second precision metal thin film resistor in series can perform equal voltage division processing on the high-precision 4.096V reference voltage, that is, a high-precision 2.048V voltage (the second reference voltage) is obtained. Wherein, the capacitor C can be set to 0.1 μF to filter the first reference voltage and the second reference voltage.

[0076] Based on the above embodiments, optionally, Figure 5 is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention. As Figure 5 shown, the constant current unit 122 includes a first operational amplifier 1221 and a third resistor R3; a first end of the first operational amplifier 1221 is connected to the reference voltage module 110, a second end of the first operational amplifier 1221, a first end of the third resistor R3, and an output end A4 of the binary commutation driving unit 121 are connected, a second end of the third resistor R3 is grounded, and a third end of the first operational amplifier 1221 is connected to an input end A3 of the binary commutation driving unit 121.

[0077] Exemplarily and optionally, the first operational amplifier 1221 includes a precision operational amplifier of model ADA4528-1, and the third resistor R3 includes a first precision metal film resistor (with a precision error less than or equal to 0.05%). Among them, the constant current unit 122 composed of the precision operational amplifier of model ADA4528-1 and the first precision metal film resistor can generate a constant current required for the operation of the thermistor Rt. If the second reference voltage is 2.048V and the resistance value of the third resistor R3 is set to 160KΩ, a high-precision constant current of 12.8 μA can be obtained.

[0078] Based on the above embodiments, optionally, Figure 6 is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention. As Figure 6 shown, the voltage processing module 140 includes a divider 141, a multiplier 142, an analog-to-digital conversion unit 143, and a data processing unit 144;

[0079] The divider 141 is respectively connected to the voltage follower module 130 and the second voltage output end D2 of the reference voltage module 110. The divider 141 is used to perform a division operation on the voltage data according to the second reference voltage to obtain first voltage processing data;

[0080] The multiplier 142 is respectively connected to the divider 141 and the first voltage output end D1 of the reference voltage module 110. The multiplier 142 is used to perform a multiplication operation on the first voltage processing data according to the first reference voltage to obtain second voltage processing data;

[0081] The analog-to-digital conversion unit 143 is respectively connected to the multiplier 142 and the first voltage output end D1 of the reference voltage module 110. The analog-to-digital conversion unit 143 is used to perform analog-to-digital conversion on the second voltage processing data according to the first reference voltage to obtain third voltage processing data;

[0082] The data processing unit 144 is connected to the analog-to-digital conversion unit 143. The data processing unit 144 is used to eliminate the error of the third voltage processed data to obtain the fourth voltage processed data, and fit the fourth voltage processed data with the temperature-voltage relationship curve to obtain the temperature data.

[0083] Specifically, the voltage follower module 130 outputs the collected voltage data to the divider 141. The divider 141 performs a division operation on the voltage data and the second reference voltage and outputs the first voltage processed data. The divider 141 outputs the first voltage processed data to the multiplier 142. The multiplier 142 performs a multiplication operation on the first reference voltage and the first voltage processed data and outputs the second voltage processed data.

[0084] Among them, the processing of the voltage data by the divider 141 and the multiplier 142 can obtain the linear relationship of the voltage data. Therefore, according to the linear relationship of the voltage data, the accuracy of the device characteristics linearly related to the voltage data can be enhanced specifically, the linearity of the temperature measurement of the temperature measurement circuit of the relative gravimeter can be improved, and thus the accuracy of the temperature measurement of the temperature measurement circuit of the relative gravimeter can be improved.

[0085] The analog-to-digital conversion unit 143 can perform analog-to-digital conversion on the second voltage processed data output by the multiplier 142 and output the digital third voltage processed data. Among them, the first reference voltage is used as the reference voltage, which can improve the accuracy of the analog-to-digital conversion unit 143 to convert the second voltage processed data into the third voltage processed data, and thus improve the accuracy of the temperature measurement of the temperature measurement circuit of the relative gravimeter to a certain extent. Among them, the third voltage processed data P is:

[0086]

[0087] Among them, n is the number of bits of the analog-to-digital conversion unit 143 (for example, the analog-to-digital conversion unit 143 includes an analog-to-digital converter of model ADS1281, and the number of bits of the analog-to-digital converter of model ADS1281 is 32 bits, so n = 32), W2 is the second voltage processed data output by the fifth output terminal F5 of the multiplier 142, Rt’ represents the resistance value of the thermistor Rt, R3’ represents the resistance value of the third resistor R3, and U represents the first reference voltage.

[0088] It can be seen from Equation (1) that the accuracy of the third voltage processed data P is related to the accuracy of the resistance values of the thermistor Rt and the third resistor R3. Therefore, ensuring the accuracy of the resistance value of the third resistor R3 and the high sensitivity of the thermistor Rt can ensure the high-precision temperature measurement of the temperature measurement circuit of the relative gravimeter.

[0089] In addition, the data processing unit 144 may collect the third voltage processing data at a fixed frequency, and process the third voltage processing data based on the three-point measurement method to eliminate the error caused by the constant current source offset included in the third voltage processing data, so as to obtain high-precision fourth voltage processing data. In addition, after the data processing unit 144 obtains the fourth voltage processing data, the fourth voltage processing data may be fitted with the temperature-voltage relationship curve to obtain accurate temperature data.

[0090] Based on the above embodiments, optionally, Figure 7 FIG. is a schematic structural diagram of another temperature measurement circuit of a relative gravimeter provided by an embodiment of the present invention. As Figure 7 shown, the divider 141 includes a first input terminal E1, a second input terminal E2, a third input terminal E3, a fourth input terminal E4, a first output terminal E5, and a second output terminal E6;

[0091] The voltage follower module 130 further includes a first output terminal C3 and a second output terminal C4; the first input terminal E1 of the divider 141 is connected to the first output terminal C3 of the voltage follower module 130, the second input terminal E2 of the divider 141 is connected to the second output terminal C4 of the voltage follower module 130, the third input terminal E3 of the divider 141 is connected to the second voltage output terminal D2 of the reference voltage module 110, and the fourth input terminal E4 and the second output terminal E6 of the divider 114 are grounded;

[0092] The divider 114 is configured to process the data input from its first input terminal E1, second input terminal E2, third input terminal E3, fourth input terminal E4, and second output terminal E6, and the first output terminal E5 outputs the first voltage processing data.

[0093] Exemplarily, optionally, the divider 141 may be constructed using a chip of model AD734. The accuracy of the divider 141 constructed using a chip of model AD734 can reach as high as 0.1%, and the time for constructing the divider 141 using a chip of model AD734 is 200 ns. The voltage across the thermistor Rt is output to the first input terminal E1 and the second input terminal E2 of the divider 141 via the voltage follower module 130 composed of the precision operational amplifier ADA4528-2. The difference between the voltage data received by the first input terminal E1 and the voltage data received by the second input terminal E2 serves as the numerator of the divider 141. The second reference voltage output by the precision voltage reference chip LTC6657BRZ-4.096V is input to the third input terminal E3 of the divider 141. The fourth input terminal E4 of the divider 141 is connected to the signal ground, and the difference between the voltage data received by the third input terminal E3 and the voltage data received by the fourth input terminal E4 serves as the denominator of the divider 141. The second output terminal E6 of the divider 141 is connected to the signal ground, and the first output terminal E5 outputs the first voltage processing data. Among them, the first voltage processing data W1 is:

[0094]

[0095] Among them, Z1 is the voltage data input to the first input terminal E1 of the divider 141, Z2 is the voltage data input to the second input terminal E2 of the divider 141, X1 is the voltage data input to the third input terminal E3 of the divider 141, X2 is the voltage data input to the fourth input terminal E4 of the divider 141, Y1 is the voltage data of the sixth input terminal E6 of the divider 141, W1 is the first voltage processing data output by the fifth output terminal E5 of the divider 141, Rt' represents the resistance value of the thermistor Rt, and R3' represents the resistance value of the third resistor R3.

[0096] It can be seen from formula (2) that the accuracy of the first voltage processing data is related to the accuracy of the resistance values of the thermistor Rt and the third resistor R3.

[0097] Based on the above embodiments, optionally, continue to refer to Figure 7 , the multiplier 142 includes a first input terminal F1, a second input terminal F2, a third input terminal F3, a fourth input terminal F4, a first output terminal F5, and a second output terminal F6;

[0098] The first input terminal F1 of the multiplier 142 is connected to the divider 141. The second input terminal F2, the fourth input terminal F4, and the second output terminal F6 of the multiplier 142 are grounded. The third input terminal F3 of the multiplier 142 is connected to the first voltage output terminal D1 of the reference voltage module 110;

[0099] The multiplier 142 is used to process the data input through its first input terminal F1, second input terminal F2, third input terminal F3, fourth input terminal F4, and second output terminal F6, and output the second voltage processed data through the first output terminal F5.

[0100] Exemplarily and optionally, the multiplier 142 can also be constructed using a chip of model AD734. The accuracy of the multiplier 142 constructed using the chip of model AD734 can reach up to 0.1%, and the time taken to construct the multiplier 142 using the chip of model AD734 is 200 ns. The divider 141 outputs the first voltage processed data to the first input terminal F1 of the multiplier 142, and the first reference voltage output by the precision voltage reference chip LTC6657BRZ-4.096V is input to the third input terminal F3 of the multiplier 142. The second input terminal F2, fourth input terminal F4, and second output terminal F6 of the multiplier 142 are grounded. Among them, the second voltage processed data W2 is:

[0101]

[0102] Wherein, Z3 is the voltage data input to the first input terminal F1 of the multiplier 142, Z4 is the voltage data input to the second input terminal F2 of the multiplier 142, X3 is the voltage data input to the third input terminal F3 of the multiplier 142, X4 is the voltage data input to the fourth input terminal F4 of the multiplier 142, Y2 is the voltage of the sixth input terminal F6 of the multiplier 142, W2 is the second voltage processed data output by the fifth output terminal F5 of the multiplier 142, Rt’ represents the resistance value of the thermistor Rt, R3’ represents the resistance value of the third resistor R3, and U represents the first reference voltage.

[0103] It can be seen from formula (3) that the accuracy of the second voltage processed data is related to the resistance value of the thermistor Rt, the resistance value of the third resistor R3, and the accuracy of the first reference voltage.

[0104] Based on the above embodiments, optionally, Figure 8 FIG. is a schematic structural diagram of another temperature measurement circuit of the relative gravimeter provided by an embodiment of the present invention. As Figure 8 shown, the data processing unit 144 includes an input terminal N1, a first output terminal N2, and a second output terminal N3;

[0105] The first output terminal N2 of the data processing unit 144 is connected to the analog-to-digital conversion unit 143, and the second output terminal N3 of the data processing unit 144 is connected to the binary commutation driving unit 121. The data processing unit 144 is used to simultaneously transmit the pulse signal generated by it to the analog-to-digital conversion unit 143 and the binary commutation driving unit 121 through its first output terminal N2 and second output terminal N3;

[0106] The input terminal N1 of the data processing unit 144 is connected to the analog-to-digital conversion unit 143, and the data processing unit 144 is used to receive the third voltage processing data.

[0107] Optionally, the data processing unit 144 includes a TM4C123X processor.

[0108] Among them, data transmission can be carried out between the analog-to-digital conversion unit 143, the data processing unit 144, and the binary commutation drive unit 121 through the SSI bus.

[0109] Specifically, the first output terminal N2 of the data processing unit 144 can send control instructions to the analog-to-digital conversion unit 143 through the SSI bus. For example, send an instruction to start the digital filtering function built in the analog-to-digital conversion unit 143, so that the analog-to-digital conversion unit 143 performs appropriate filtering processing on the converted third voltage processing data. Send a pulse signal to control the rate of sampling and conversion of the third voltage processing data obtained by the analog-to-digital conversion unit 143. The second output terminal N2 of the data processing unit 144 can send a pulse signal to the binary commutation drive unit 121 through the SSI bus to control the alternating change of the constant current flowing through the thermistor Rt.

[0110] It should be noted that: the data processing unit 144 transmits the pulse signal to both the analog-to-digital conversion unit 143 and the binary commutation drive unit 121 at the same time, thereby ensuring the real-time synchronization of the drive of the thermistor Rt in the binary commutation drive unit 121 and the sampling conversion of the analog-to-digital conversion unit 143, and then realizing high-precision temperature information acquisition and processing.

[0111] The analog-to-digital conversion unit 143 can transmit the third voltage processing data to the input terminal N1 of the data processing unit 144 through the SSI bus. The data processing unit 144 can collect the third voltage processing data at a fixed frequency and process the third voltage processing data based on the three-point measurement method to eliminate the error caused by the constant current source offset included in the third voltage processing data, so as to obtain high-precision fourth voltage processing data. After the data processing unit 144 obtains the fourth voltage processing data, it performs data fitting on the collected fourth voltage processing data according to the temperature-voltage relationship curve to obtain accurate temperature data.

[0112] Figure 9 It is an ideal constant current schematic diagram output by a constant current unit provided by an embodiment of the present invention. Figure 10 It is an actual constant current schematic diagram output by a constant current unit provided by an embodiment of the present invention. Compare Figure 9 and Figure 10It can be known that the constant current output by the constant current unit in actual work has a drift phenomenon. Among them, the constant current drift within a short period of time is regarded as linear drift, so the constant current drift amount within a short period of time is a constantly increasing constant current drift amount. At this time, the three-point measurement method can be used to process the data of the third voltage processing to obtain high-precision data of the fourth voltage processing.

[0113] Based on the above embodiments, optionally, the specific process of the data processing unit processing the third voltage processing data based on the three-point temperature measurement method is as follows:

[0114] Exemplarily, continuing to refer to Figure 8 , the pulse signal generated by the data processing unit 144 is a PWM square wave (50% high and low levels) to control the driving of the thermistor Rt in the binary commutation driving unit 121. When the square wave signal is at a low level, the first analog switch S1 and the fourth analog switch S4 are disconnected, and the second analog switch S2 and the third analog switch S3 are closed. The driving direction of the constant current is from the first end of the thermistor Rt to the second end of the thermistor Rt. At this time, the analog-to-digital conversion unit 143 performs data sampling, and multiple third voltage processing data need to be continuously sampled (the sampling frequency of the analog-to-digital conversion unit 143 is appropriately greater than the control frequency of the square wave signal), and after the analog-to-digital conversion unit 143 filters the third voltage processing data, a third voltage processing data is output to the data processing unit 144. When the square wave signal is at a high level, the first analog switch S1 and the fourth analog switch S4 are closed, and the second analog switch S2 and the third analog switch S3 are disconnected. The driving direction of the constant current is from the second end of the thermistor Rt to the first end of the thermistor Rt. At this time, the analog-to-digital conversion unit 143 performs data sampling, and multiple third voltage processing data need to be continuously sampled (the sampling frequency of the analog-to-digital conversion unit 143 is appropriately greater than the control frequency of the square wave signal), and after the analog-to-digital conversion unit 143 filters the third voltage processing data, a third voltage processing data is output to the data processing unit 144. The above high and low level cycle control is regarded as a driving cycle, and the processing unit 144 can obtain 3 filtered data in each half driving cycle. Among them, the fourth voltage processing data W3 is:

[0115]

[0116] Among them, Q1, Q2, and Q3 are respectively the three filtered third voltage processing data received by the data processing unit 144 in sequence within a half driving cycle, n is the number of bits of the analog-to-digital conversion unit 143 (for example, the analog-to-digital conversion unit 143 includes an analog-to-digital converter of model ADS1281, and the number of bits of the analog-to-digital converter of model ADS1281 is 32 bits, so n = 32), Rt' represents the resistance value of the thermistor Rt, and R3' represents the resistance value of the third resistor R3.

[0117] As can be seen from formula (4), the three-point measurement method can eliminate the influence of the constant current source offset, and the temperature measurement accuracy depends on the accuracy of the thermistor Rt and the third resistor R3.

[0118] Figure 11 FIG. 4 is a schematic structural diagram of a relative gravimeter provided by an embodiment of the present invention. The relative gravimeter 01 includes a temperature measurement circuit 02 of the relative gravimeter provided by any embodiment of the present invention, and thus has the beneficial effects of the temperature measurement circuit 02 of the relative gravimeter provided by the embodiment of the present invention, which will not be elaborated herein.

[0119] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, which is not limited herein.

[0120] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A temperature measurement circuit for a relative gravimeter, characterized in that: Comprising: A reference voltage module, a binary commutation constant current module, a voltage follower module, and a voltage processing module; The binary commutation constant current module includes a binary commutation driving unit and a constant current unit; The reference voltage module is respectively connected to the constant current unit and the voltage processing module. The reference voltage module is used to provide a reference voltage to the constant current unit and the voltage processing module. The constant current unit is used to generate a constant current according to the reference voltage; The reference voltage module includes a first voltage output terminal and a second voltage output terminal; The first voltage output terminal of the reference voltage module is used to output a first reference voltage, and the second voltage output terminal of the reference voltage module is used to output a second reference voltage; The binary commutation driving unit is respectively connected to the constant current unit, the voltage follower module, and the voltage processing module. The voltage processing module is used to control the flow direction of the constant current flowing through the binary commutation driving unit to alternate. The voltage follower module is used to collect voltage data at the driving end of the binary commutation driving unit; The voltage follower module is connected to the voltage processing module. The voltage processing module is used to eliminate the error of the voltage data and obtain temperature data according to the voltage data after eliminating the error; The voltage processing module includes a divider, a multiplier, an analog-to-digital conversion unit, and a data processing unit; The divider is respectively connected to the voltage follower module and the second voltage output terminal of the reference voltage module. The divider is used to perform a division operation on the voltage data according to the second reference voltage to obtain first voltage processing data; The multiplier is respectively connected to the divider and the first voltage output terminal of the reference voltage module. The multiplier is used to perform a multiplication operation on the first voltage processing data according to the first reference voltage to obtain second voltage processing data; The analog-to-digital conversion unit is respectively connected to the multiplier and the first voltage output terminal of the reference voltage module. The analog-to-digital conversion unit is used to perform analog-to-digital conversion on the second voltage processing data according to the first reference voltage to obtain third voltage processing data; The data processing unit is connected to the analog-to-digital conversion unit. The data processing unit is used to eliminate the error of the third voltage processing data to obtain fourth voltage processing data, and fit the fourth voltage processing data with the temperature-voltage relationship curve to obtain the temperature data.

2. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The binary commutation driving unit includes a first analog switch, a second analog switch, a third analog switch, a fourth analog switch, and a thermistor; The binary commutation driving unit includes a first driving end, a second driving end, an input end, and an output end; The constant current unit includes a first input end and an output end; The first ends of the first analog switch and the second analog switch are connected and serve as the output end of the binary commutation driving unit to be connected to the first input end of the constant current unit; the first ends of the third analog switch and the fourth analog switch are connected and serve as the input end of the binary commutation driving unit to be connected to the output end of the constant current unit; the second ends of the first analog switch and the third analog switch are both connected to the first end of the thermistor and serve as the first driving end of the binary commutation driving unit; the second ends of the second analog switch and the fourth analog switch are both connected to the second end of the thermistor and serve as the second driving end of the binary commutation driving unit; The first analog switch, the second analog switch, the third analog switch, and the fourth analog switch are all connected to the voltage processing module, and the voltage processing module is used to control the on / off states of the first analog switch, the second analog switch, the third analog switch, and the fourth analog switch.

3. The temperature measurement circuit of the relative gravimeter according to claim 2, characterized in that: The voltage follower module includes a first input end and a second input end; The first input end of the voltage follower module is connected to the first driving end of the binary commutation driving unit, and the first input end of the voltage follower module is used to collect the voltage data of the first end of the thermistor; The second input end of the voltage follower module is connected to the second driving end of the binary commutation driving unit, and the second input end of the voltage follower module is used to collect the voltage data of the second end of the thermistor.

4. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The constant current unit includes a first operational amplifier and a third resistor; The first end of the first operational amplifier is connected to the reference voltage module, the second end of the first operational amplifier, the first end of the third resistor, and the output end of the binary commutation driving unit are connected, the second end of the third resistor is grounded, and the third end of the first operational amplifier is connected to the input end of the binary commutation driving unit.

5. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The reference voltage module further includes a reference voltage chip, a first resistor, a second resistor, and a capacitor; The input end of the reference voltage chip is connected to an external power supply; The output end of the reference voltage chip, the first end of the capacitor, and the first end of the first resistor are connected and serve as the first voltage output end of the reference voltage module; the second end of the first resistor is connected to the second end of the second resistor and serves as the second voltage output end of the reference voltage module; the second end of the capacitor and the second end of the second resistor are grounded together.

6. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The divider includes a first input end, a second input end, a third input end, a fourth input end, a first output end, and a second output end; The voltage follower module further includes a first output end and a second output end; the first input end of the divider is connected to the first output end of the voltage follower module, the second input end of the divider is connected to the second output end of the voltage follower module, the third input end of the divider is connected to the second voltage output end of the reference voltage module, and the fourth input end and the second output end of the divider are grounded; The divider is used to process data input through its first input terminal, second input terminal, third input terminal, fourth input terminal and second output terminal, and the first output terminal outputs first voltage processed data.

7. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The multiplier includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, a first output terminal and a second output terminal; The first input terminal of the multiplier is connected to the divider, the second input terminal, the fourth input terminal and the second output terminal of the multiplier are grounded, and the third input terminal of the multiplier is connected to the first voltage output terminal of the reference voltage module; The multiplier is used to process data input through its first input terminal, second input terminal, third input terminal, fourth input terminal and second output terminal, and the first output terminal outputs second voltage processed data.

8. The temperature measurement circuit of the relative gravimeter according to claim 1, characterized in that: The data processing unit includes an input terminal, a first output terminal and a second output terminal; The first output terminal of the data processing unit is connected to the analog-to-digital conversion unit, the second output terminal of the data processing unit is connected to the binary commutation drive unit, and the data processing unit is used to simultaneously transmit the pulse signal generated by it to the analog-to-digital conversion unit and the binary commutation drive unit through its first output terminal and second output terminal; The input terminal of the data processing unit is connected to the analog-to-digital conversion unit, and the data processing unit is used to receive the third voltage processed data.

9. A relative gravimeter, characterized in that, A temperature measurement circuit of the relative gravimeter according to any one of claims 1-8 is included.

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