Integrated circuit module for LVDT measurement
By designing integrated circuit modules, combining analog and digital circuits, and incorporating internal temperature calibration, the problems of large space occupation, high cost, and low accuracy of LVDT measurement circuits were solved, achieving improved integration and anti-interference capabilities.
Patent Information
- Application Number
- CN202520370686.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2035-03-05
AI Technical Summary
Existing LVDT measurement circuits suffer from problems such as large space occupation, high cost, poor integration and weak anti-interference ability, and the measurement accuracy is greatly affected by temperature.
Design an integrated circuit module comprising a main control unit, a push-pull circuit, a peak detection circuit, a temperature detection circuit, a drive signal output circuit, and a communication module. By integrating analog and digital circuits, the module enables the driving and signal measurement of an LVDT (Low Temperature Detector), and improves measurement accuracy by calibrating temperature drift using an internal temperature sensor.
It achieves high integration of circuit modules, reduces external components, improves anti-interference ability, reduces space occupation, and improves measurement accuracy through temperature drift calibration.
Smart Images
Figure CN223727162U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to LVDT measurement circuit technical field more specifically, relate to a kind of integrated circuit module of LVDT measurement. BACKGROUND
[0002] LVDT sensor is widely used in linear displacement detection in position servo mechanism.LVDT is the abbreviation of Linear Variable Differential Transformer, and its working principle can be simply described as movable transformer.The LVDT sensor usually includes four signal lines, including two primary side signal lines and two secondary side signal lines.The displacement detection principle is that sinusoidal voltage signal is input on the primary side signal line, and then the amplitude of the secondary output sinusoidal voltage signal is extracted, which is proportional to the linear displacement.
[0003] However, the LVDT measurement circuit currently used is either an analog circuit composed of operational amplifier, resistance and capacitance, etc., which occupies a large space on the circuit board and affects the miniaturization design of the sensor, or a CPU such as DSP or PFGA, which is combined with an external signal conditioning circuit to realize, and has high cost, poor integration, poor anti-interference ability, poor measurement accuracy affected by temperature, and the present utility model provides a new solution to the above problems. SUMMARY
[0004] In view of the problems existing in the prior art, the purpose of the present utility model is to provide an integrated circuit module for LVDT measurement to solve the technical problems mentioned in the background art.
[0005] To solve the above problems, the utility model adopts the following technical scheme.
[0006] An integrated circuit module for LVDT measurement includes an LVDT, one end of the primary side of the LVDT is grounded through a capacitor, and further includes a main control unit, a push-pull circuit, a peak detection circuit, a temperature detection circuit, a drive signal output circuit, a communication module and a memory. The input end of the push-pull circuit is electrically connected to the other end of the primary side of the LVDT, and the output end of the push-pull circuit is electrically connected to the PWM port of the main control unit. The other end of the primary side of the LVDT is connected to the peak detection circuit, which is provided with two groups. The two groups of peak detection circuits are respectively arranged at one end of the two groups of secondary sides of the LVDT, and the other end of the two groups of secondary sides of the LVDT is grounded. The analog signal connection end of the peak detection circuit is connected to the ADC port of the main control unit, and the digital signal connection end of the peak detection circuit is connected to the DO port of the main control unit.
[0007] Preferably, one end of the secondary side of the LVDT is electrically connected to the input end of the peak detection circuit, the master control unit is provided with an ADC1 port, an ADC2 port, an ADC3 port, an ADC4 port, a DO1 port, a DO2 port, a DAC port, the analog signal connection end of one group of the peak detection circuits is connected to the ADC2 port of the master control unit, the digital signal connection end of one group of the peak detection circuits is connected to the DO1 port of the master control unit, the analog signal connection end of another group of the peak detection circuits is connected to the ADC3 port of the master control unit, and the digital signal connection end of another group of the peak detection circuits is connected to the DO2 port of the master control unit.
[0008] Preferably in any of the above schemes, the other end of the primary side of the LVDT is electrically connected to the ADC1 port of the master control unit.
[0009] Preferably in any of the above schemes, the temperature detection circuit is connected to the ADC4 port of the master control unit.
[0010] Preferably in any of the above schemes, the signal input end of the driving signal output circuit is connected to the DAC port of the master control unit.
[0011] Preferably in any of the above schemes, the master control unit is further provided with a TTL port, and the communication module is connected to the TTL port.
[0012] Preferably in any of the above schemes, the master control unit preferably uses an MCU chip.
[0013] Compared with the prior art, the application has the following advantages:
[0014] In the application, the master control unit, the push-pull circuit, the peak detection circuit, the temperature detection circuit, the driving signal output circuit, the communication module and the memory are designed, the entire circuit module has high integration, the use of peripheral devices is reduced, the anti-interference capability is improved, the occupied space of the measurement circuit and the auxiliary circuit can be greatly reduced, the internal temperature sensor is used for calibrating temperature drift, reducing the influence of temperature drift and improving the measurement precision. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a typical application circuit diagram of the integrated circuit module for LVDT measurement of the application;
[0016] Figure 2 It is an internal circuit diagram of the integrated circuit module for LVDT measurement of the application;
[0017] Figure 3 It is an output signal waveform and time point description diagram;
[0018] Figure 4 Fig. 3 is a signal diagram of the peak detection circuit;
[0019] Figure 5 Fig. 4 is a flow chart of the measurement process;
[0020] Figure 6 Fig. 5 is a flow chart of the linear calibration process;
[0021] Figure 7 Fig. 6 is a flow chart of the temperature drift calibration process.
[0022] Explanation of reference numerals in the drawings:
[0023] 1, master unit; 2, push-pull circuit; 3, peak detection circuit; 6, temperature detection circuit. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0025] Embodiment:
[0026] Please refer to Figures 1 to 2 An integrated circuit module for LVDT measurement, comprising an LVDT, one end of the primary side of the LVDT is grounded through a set capacitor, characterized in that: further comprising a master unit, a push-pull circuit, a peak detection circuit, a temperature detection circuit, a driving signal output circuit, a communication module, a memory, one end of the primary side of the LVDT is electrically connected to the input end of the push-pull circuit, the other end of the primary side of the LVDT is electrically connected to one of the ADC ports of the master unit, the output end of the push-pull circuit is electrically connected to the PWM end of the master unit, and the other end of the primary side of the LVDT is connected to the peak detection circuit, which is provided with two groups, the two groups of peak detection circuits are respectively arranged at one end of the two groups of secondary sides of the LVDT, the other end of the two groups of secondary sides of the LVDT is grounded, the analog signal connection end of the peak detection circuit is connected to the ADC port of the master unit, and the digital signal connection end of the peak detection circuit is connected to the DO port of the master unit.
[0027] In the embodiment, the master control unit is provided with an ADC1 port, an ADC2 port, an ADC3 port, an ADC4 port, a DO1 port, a DO2 port and a DAC port, the analog signal connection end of one group of the peak detection circuits is connected to the ADC2 port of the master control unit, the digital signal connection end of one group of the peak detection circuits is connected to the DO1 port of the master control unit, the analog signal connection end of another group of the peak detection circuits is connected to the ADC3 port of the master control unit, and the digital signal connection end of another group of the peak detection circuits is connected to the DO2 port of the master control unit.
[0028] In the embodiment, the other end of the primary side of the LVDT is electrically connected to the ADC1 port of the master control unit.
[0029] In the embodiment, the temperature detection circuit is connected to the ADC4 port of the master control unit.
[0030] In the embodiment, the signal input end of the driving signal output circuit is connected to the DAC port of the master control unit.
[0031] In the embodiment, the master control unit is provided with a TTL port, and the communication module is connected to the TTL port.
[0032] In the embodiment, the master control unit preferably uses an MCU chip.
[0033] The working process of the utility model is as follows:
[0034] The master control block diagram is shown in Figure 2 By integrating analog circuits and digital circuits, LVDT driving and single module measurement of signals are realized, specifically:
[0035] Step one: the LVDT driving is driven through the PWM driving push-pull circuit 2, the P1 of the external LVDT primary side is connected in series with the C0 capacitor to form an LC resonance network, each parameter is adjusted according to formula 1, and the driving signal shown in Figure 3 is realized.
[0036]
[0037] Through the feedback of the ADC1, whether the driving signal meets the test requirements is detected, the fuzzy control mode is compared with the rule library analysis of the MCU, if the requirements are met, the measurement is started, if the driving signal is unqualified, the fault information is uploaded through the communication module 8 and the measurement is stopped and re-detected, so as to avoid affecting the measurement accuracy.
[0038] Step two: the LVDT core is at different positions, and the two-way secondary side Q3, Q4 signals are as shown in Figure 3As shown, the peak value of the two signals is different with different core position, the peak value of the signal is measured by peak detection circuit 3, and the core position is calculated by ADC2, ADC3 measurement;
[0039] To improve the measurement accuracy and response speed, the capacitance C1, C2 of the peak detection circuit is increased by discharging switch Q3, Q4, as shown in Figure 3 The PWM time point, T1, opens Q3, Q4 switch, and the capacitor starts charging, and the ADC sampling starts when the output signal reaches the peak value at T3, and Q3, Q4 is closed at T4, and the capacitor is discharged quickly, and the peak detection output voltage is as shown in Figure 4 The capacitor is completely discharged before it starts charging again at T4 to avoid affecting the next measurement, and the measurement process is as shown in Figure 5
[0040] Step three: to improve the measurement accuracy and eliminate the linear difference of LVDT, linear calibration function is added, and the calibration process is as shown in Figure 6
[0041] The core position is calculated first according to the current measured AD value (AD = ADC2-ADC3), and the position of AD in the calibration parameter table is determined by table lookup, for example: AD n-1 <AD<AD n The core position is calculated according to formula 2:
[0042]
[0043] Step four: through the temperature detection circuit 6 inside the module, the sensor temperature drift is compensated, and the calibration process is as shown in Figure 7
[0044] When calculating the core position, the current measurement temperature T is first combined to calculate the temperature drift coefficient at the current temperature according to formula 3, and then the core position is calculated according to formula 4:
[0045]
[0046] P = P T0 *K T ……………………………(formula 4).
[0047] Temperature compensation parameters and linear calibration parameters are stored in EEPROM 4;
[0048] Through the drive signal output circuit 7, 0-5V signal output can be realized, and the output signal is corresponding to the core position through the DAC output of MCU;
[0049] Through the communication module 8 and the MCU communication interface, RS485, CAN communication is realized;
[0050] Sensor debugging, calibration, diagnostic information output, etc. communicate with external devices (including but not limited to PC software) through RS485 or CAN.
[0051] The above merely provides the preferred embodiments of the present application; however, the protection scope of the present application is not limited thereto. Any skilled person in the art, according to the technical scheme and the improvement concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. An integrated circuit module for LVDT measurement comprising an LVDT, one end of the primary winding of the LVDT is grounded through a set capacitor, characterized in that: The application also comprises a master control unit, a push-pull circuit, a peak detection circuit, a temperature detection circuit, a driving signal output circuit, a communication module, and a memory; one end of the primary side of the LVDT is electrically connected to the other end of the input end of the push-pull circuit, and the other end of the primary side of the LVDT is electrically connected to one of the ADC ports of the master control unit; the output end of the push-pull circuit is electrically connected to the PWM port of the master control unit; two groups of the peak detection circuit are arranged on the other end of the primary side of the LVDT; the two groups of the peak detection circuit are arranged on one end of the two groups of the secondary side of the LVDT; the other end of the two groups of the secondary side of the LVDT is grounded; the analog signal connection end of the peak detection circuit is connected to the ADC port of the master control unit; and the digital signal connection end of the peak detection circuit is connected to the DO port of the master control unit.
2. An LVDT measuring integrated circuit module according to claim 1, characterized in that: One end of the secondary side of the LVDT is electrically connected to the input end of the peak detection circuit; the master control unit is provided with an ADC1 port, an ADC2 port, an ADC3 port, an ADC4 port, a DO1 port, a DO2 port, and a DAC port; the analog signal connection end of one group of the peak detection circuit is connected to the ADC2 port of the master control unit; the digital signal connection end of one group of the peak detection circuit is connected to the DO1 port of the master control unit; the analog signal connection end of the other group of the peak detection circuit is connected to the ADC3 port of the master control unit; and the digital signal connection end of the other group of the peak detection circuit is connected to the DO2 port of the master control unit.
3. An LVDT measuring integrated circuit module according to claim 2, characterized in that: The other end of the primary side of the LVDT is electrically connected to the ADC1 port of the master control unit.
4. An LVDT measuring integrated circuit module according to claim 2, characterized in that: The temperature detection circuit is connected to the ADC4 port of the master control unit.
5. An LVDT measuring integrated circuit module according to claim 2, characterized in that: The signal input end of the driving signal output circuit is connected to the DAC port of the master control unit.
6. An LVDT measuring integrated circuit module according to claim 1, characterized in that: The master control unit is provided with a TTL port, and the communication module is connected to the TTL port.
7. An LVDT measuring integrated circuit module according to claim 1, characterized in that: The master control unit preferably uses an MCU chip.