Control circuit of eddy current displacement sensor

Abstract

The utility model relates to the technical field of eddy current displacement sensors, in particular to a control circuit of an eddy current displacement sensor, which comprises an oscillating circuit, a pulse width detection circuit, a voltage detection circuit, an amplifying circuit and an MCU (Microprogrammed Control Unit) main control circuit, and is characterized in that the oscillating circuit comprises a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors; the first capacitor and the coil probe form LC oscillation, and the analog electronic switch is controlled by the MCU main control circuit to select the corresponding channel to increase or decrease the second capacitor, so that different LC resonant frequencies can be generated, and the MCU main control circuit can identify different oscillation frequencies, thereby being capable of automatically identifying different ranges. And therefore, various coil probes with different lengths can be compatible.

Description

Technical Field

[0001] The utility model relates to the technical field of eddy current displacement sensors, in particular to a control circuit of an eddy current displacement sensor. Background Art

[0002] Eddy current displacement sensors have been widely used in the detection field due to their many advantages such as non-contact, large measuring range, high sensitivity, simple structure, and no influence from non-metallic materials. Eddy current displacement sensors on the market generally include three parts: coil probe, high-frequency connecting cable and front-end circuit. The front-end circuit includes oscillation circuit, detection circuit and signal conversion circuit, etc. However, since the existing oscillation circuit can only generate one oscillation frequency, it can only be adapted to one displacement sensor probe, which in turn makes it incompatible with multiple coil probes of different lengths. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a control circuit of an eddy current displacement sensor, which can be compatible with multiple coil probes of different lengths.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0005] A control circuit of an eddy current displacement sensor comprises an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplification circuit and an MCU main control circuit, wherein the MCU main control circuit is electrically connected to the oscillation circuit, the pulse width detection circuit, the voltage detection circuit and the amplification circuit respectively, the oscillation circuit is electrically connected to a coil probe, a pulse width detection circuit and a voltage detection circuit of the eddy current displacement sensor respectively, the oscillation circuit comprises a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors, the first capacitor is connected in parallel with the coil probe of the eddy current displacement sensor, a plurality of the second capacitors are connected in parallel with each other, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, the other end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to one end of the analog electronic switch U1, the pulse width detection circuit, the voltage detection circuit and a plurality of the second capacitors connected in parallel respectively, and the analog electronic switch U1 is electrically connected to the MCU main control circuit and the plurality of the second capacitors respectively.

[0006] Furthermore, the model of the analog electronic switch U1 is TS5A23166DCUR, the number of the second capacitors is two, the two second capacitors are capacitor C1 and capacitor C2 respectively, the second pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C1, the sixth pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C2, the other end of the capacitor C1 is electrically connected to the other end of the capacitor C2, the other end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor, the pulse width detection circuit and the voltage detection circuit respectively, and the analog electronic switch The first pin of U1 is electrically connected to the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, respectively, and the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1 are all connected to a 5V power supply, the third pin and the seventh pin of the analog electronic switch U1 are both electrically connected to the MCU main control circuit, and the fourth pin of the analog electronic switch U1 is grounded.

[0007] Furthermore, it also includes a capacitor C6, one end of which is electrically connected to the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, and one end of the capacitor C6 is connected to a 5V power supply, and the other end of the capacitor C6 is grounded.

[0008] Furthermore, it also includes a magnetically controlled switch, which is electrically connected to the MCU main control circuit.

[0009] Furthermore, it also includes an Internet of Things module, which is electrically connected to the MCU main control circuit.

[0010] The beneficial effects of the utility model are:

[0011] The control circuit of the present scheme includes an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplification circuit and an MCU main control circuit. The oscillation circuit includes a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors. The first capacitor is connected in parallel with the coil probe of the eddy current displacement sensor, and the plurality of second capacitors are connected in parallel with each other. One end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, and the other end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is respectively electrically connected to one end of the analog electronic switch U1 and the plurality of second capacitors connected in parallel. The analog electronic switch U1 is respectively electrically connected to the MCU main control circuit and the plurality of second capacitors. The first capacitor and the coil probe form an LC oscillation. The MCU main control circuit controls the analog electronic switch to select the corresponding channel to increase or decrease the second capacitor, so that different LC resonant frequencies can be generated. The MCU main control circuit can identify different oscillation frequencies, thereby automatically identifying different measuring ranges, and thus being compatible with a variety of coil probes of different lengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a circuit schematic diagram of the control circuit of the eddy current displacement sensor of the utility model;

[0013] Description of labels:

[0014] 1. Oscillation circuit; 2. Pulse width detection circuit; 3. Voltage detection circuit; 4. Amplification circuit; 5. MCU main control circuit; 6. Internet of Things module; 7. LED display circuit; 8. Output circuit; 9. Magnetic control switch; 10. Coil probe. DETAILED DESCRIPTION

[0015] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0016] Please refer to Figure 1 , the technical solution adopted by the utility model is:

[0017] A control circuit of an eddy current displacement sensor comprises an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplification circuit and an MCU main control circuit, wherein the MCU main control circuit is electrically connected to the pulse width detection circuit, the voltage detection circuit and the amplification circuit respectively, the oscillation circuit comprises a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors, the first capacitor is connected in parallel with a coil probe of the eddy current displacement sensor, a plurality of the second capacitors are connected in parallel with each other, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, the other end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to one end of the analog electronic switch U1, the pulse width detection circuit, the voltage detection circuit and a plurality of second capacitors connected in parallel respectively, and the analog electronic switch U1 is electrically connected to the MCU main control circuit and the plurality of second capacitors respectively.

[0018] From the above description, it can be seen that the beneficial effects of the utility model are:

[0019] The control circuit of the present scheme includes an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplification circuit and an MCU main control circuit. The oscillation circuit includes a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors. The first capacitor is connected in parallel with the coil probe of the eddy current displacement sensor, and the plurality of second capacitors are connected in parallel with each other. One end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, and the other end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor is respectively electrically connected to one end of the analog electronic switch U1 and the plurality of second capacitors connected in parallel. The analog electronic switch U1 is respectively electrically connected to the MCU main control circuit and the plurality of second capacitors. The first capacitor and the coil probe form an LC oscillation. The MCU main control circuit controls the analog electronic switch to select the corresponding channel to increase or decrease the second capacitor, so that different LC resonant frequencies can be generated. The MCU main control circuit can identify different oscillation frequencies, thereby automatically identifying different measuring ranges, and thus being compatible with a variety of coil probes of different lengths.

[0020] Furthermore, the model of the analog electronic switch U1 is TS5A23166DCUR, the number of the second capacitors is two, the two second capacitors are capacitor C1 and capacitor C2 respectively, the second pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C1, the sixth pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C2, the other end of the capacitor C1 is electrically connected to the other end of the capacitor C2, the other end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor, the pulse width detection circuit and the voltage detection circuit respectively, and the analog electronic switch The first pin of U1 is electrically connected to the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, respectively, and the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1 are all connected to a 5V power supply, the third pin and the seventh pin of the analog electronic switch U1 are both electrically connected to the MCU main control circuit, and the fourth pin of the analog electronic switch U1 is grounded.

[0021] Furthermore, it also includes a capacitor C6, one end of which is electrically connected to the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, and one end of the capacitor C6 is connected to a 5V power supply, and the other end of the capacitor C6 is grounded.

[0022] It can be seen from the above description that capacitor C6 plays a filtering role and can filter the power supply.

[0023] Furthermore, it also includes a magnetically controlled switch, which is electrically connected to the MCU main control circuit.

[0024] From the above description, it can be seen that the magnetic control switch is used to replace the traditional button. During the installation and debugging of the equipment, there is no need to open the back cover. The magnetic control switch facilitates calibration and setting.

[0025] Furthermore, it also includes an Internet of Things module, which is electrically connected to the MCU main control circuit.

[0026] From the above description, it can be seen that the Internet of Things module can realize long-distance data transmission and update data in real time, avoiding manual on-site program upgrades and data downloads, greatly improving work efficiency.

[0027] Please refer to Figure 1 , Embodiment 1 of the present utility model is:

[0028] A control circuit of an eddy current displacement sensor, comprising an oscillation circuit 1, a pulse width detection circuit 2, a voltage detection circuit 3, an amplifier circuit 4 and an MCU main control circuit 5, wherein the MCU main control circuit 5 is electrically connected to the pulse width detection circuit 2, the voltage detection circuit 3 and the amplifier circuit 4 respectively, and the oscillation circuit 1 comprises a first capacitor, at least one analog electronic switch U1 (in this embodiment, there are two analog electronic switches, please refer to Figure 1 , and an analog electronic switch U2, the number of analog electronic switches can be reasonably set according to actual conditions) and several second capacitors, the first capacitor is connected in parallel with the coil probe 10 of the eddy current displacement sensor, and several second capacitors are connected in parallel with each other, one end of the first capacitor after being connected in parallel with the coil probe 10 of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, and the other end of the first capacitor after being connected in parallel with the coil probe 10 of the eddy current displacement sensor is respectively electrically connected to the analog electronic switch U1, the pulse width detection circuit 2, the voltage detection circuit 3 and one end of the several second capacitors after being connected in parallel, and the analog electronic switch U1 is respectively electrically connected to the MCU main control circuit 5 and the several second capacitors.

[0029] The model of the analog electronic switch U1 is TS5A23166DCUR, the number of the second capacitors is two, the two second capacitors are capacitor C1 (capacitance value is 47nF) and capacitor C2 (capacitance value is 10nF), the second pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C1, the sixth pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C2, the other end of the capacitor C1 is electrically connected to the other end of the capacitor C2, the other end of the first capacitor connected in parallel with the coil probe 10 of the eddy current displacement sensor, the pulse width detection circuit 2 and the voltage detection circuit 3, respectively. The first pin of the analog electronic switch U1 is electrically connected to the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe 10 of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, respectively, and the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe 10 of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1 are all connected to a 5V power supply, the third pin and the seventh pin of the analog electronic switch U1 are both electrically connected to the MCU main control circuit 5, and the fourth pin of the analog electronic switch U1 is grounded.

[0030] It also includes a capacitor C6 (capacitance value is 4.7μF), one end of which is electrically connected to the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe 10 of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, and one end of the capacitor C6 is connected to a 5V power supply, and the other end of the capacitor C6 is grounded.

[0031] It also includes a magnetically controlled switch 9 (model SLSS49E), which is electrically connected to the MCU main control circuit 5.

[0032] It also includes an Internet of Things module 6, which is electrically connected to the MCU main control circuit 5.

[0033] It also includes an LED display circuit 7 and a 4-20mA output circuit 8 , and both the LED display circuit 7 and the 4-20mA output circuit 8 are electrically connected to the MCU main control circuit 5 .

[0034] The pulse width detection circuit 2, voltage detection circuit 3, amplifier circuit 4, MCU main control circuit 5, Internet of Things module 6, LED display circuit 7 and 4-20mA output circuit 8 all adopt circuits that can realize corresponding functions in the prior art.

[0035] The working principle of the above control circuit is:

[0036] The oscillation circuit 1 generates a high-frequency oscillating current, which enters the coil probe 10 through the connecting cable. The coil probe 10 generates a high-frequency changing induced magnetic field. When the object to be measured is close to the probe, eddy current is generated on the object to be measured, and the eddy current regenerates the eddy current magnetic field. The direction of the magnetic lines of force is opposite to the direction of the magnetic field of the coil probe 10, which changes the coil impedance, causing the oscillation voltage of the oscillation circuit 1 to change. The oscillation voltage after oscillation passes through the voltage detection circuit 3 and is filtered, and then passes through the amplifier circuit 4 to form an output voltage that is sent to the MCU main control circuit 5 for voltage AD sampling; at the same time, the oscillation voltage after oscillation passes through the pulse width detection circuit 2, is converted into a square wave, and is sent to the PWM input port of the MCU main control circuit 5 for pulse width sampling; after the collected data is calculated by the MCU main control circuit 5, the data is output to the LED display circuit 7 through the IO for display, and at the same time, it is output in the form of current through the 4-20mA output circuit 8, and the data can also be remotely transmitted through the Internet of Things module 6 for real-time monitoring.

[0037] In the oscillation circuit 1, the first capacitor and the coil probe 10 form an LC oscillation, and the MCU main control circuit 5 controls the analog electronic switch to select the corresponding channel to increase or decrease the second capacitor, so that different LC resonant frequencies can be generated, thereby being compatible with a variety of signal output capabilities, facilitating the selection of signal types, and thus being compatible with a variety of coil probes with different lengths.

[0038] In summary, the utility model provides a control circuit of an eddy current displacement sensor, including an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplification circuit and an MCU main control circuit. The oscillation circuit includes a first capacitor, at least one analog electronic switch U1 and a plurality of second capacitors. The first capacitor is connected in parallel with the coil probe of the eddy current displacement sensor, and the plurality of second capacitors are connected in parallel with each other. One end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, and the other end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor is respectively electrically connected to one end after the analog electronic switch U1 and the plurality of second capacitors are connected in parallel. The analog electronic switch U1 is respectively electrically connected to the MCU main control circuit and the plurality of second capacitors. The first capacitor and the coil probe form an LC oscillation. The MCU main control circuit controls the analog electronic switch to select the corresponding channel to increase or decrease the second capacitor, so that different LC resonant frequencies can be generated. The MCU main control circuit can identify different oscillation frequencies, thereby automatically identifying different measuring ranges, and thus being compatible with a variety of coil probes of different lengths.

[0039] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A control circuit of an eddy current displacement sensor, comprising an oscillation circuit, a pulse width detection circuit, a voltage detection circuit, an amplifier circuit and an MCU main control circuit, wherein the MCU main control circuit is electrically connected to the pulse width detection circuit, the voltage detection circuit and the amplifier circuit respectively, and characterized in that: The oscillation circuit includes a first capacitor, at least one analog electronic switch U1 and several second capacitors. The first capacitor is connected in parallel with the coil probe of the eddy current displacement sensor, and several second capacitors are connected in parallel with each other. One end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor is electrically connected to the analog electronic switch U1, and the other end of the first capacitor after being connected in parallel with the coil probe of the eddy current displacement sensor is respectively electrically connected to one end of the analog electronic switch U1, the pulse width detection circuit, the voltage detection circuit and several second capacitors connected in parallel. The analog electronic switch U1 is respectively electrically connected to the MCU main control circuit and the several second capacitors.

2. The control circuit of the eddy current displacement sensor according to claim 1, characterized in that: The model of the analog electronic switch U1 is TS5A23166DCUR, the number of the second capacitors is two, the two second capacitors are capacitor C1 and capacitor C2, the second pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C1, the sixth pin of the analog electronic switch U1 is electrically connected to one end of the capacitor C2, the other end of the capacitor C1 is electrically connected to the other end of the capacitor C2, the other end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, the pulse width detection circuit and the voltage detection circuit, respectively, the analog electronic switch U1 The first pin is electrically connected to the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, respectively, and the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1 are all connected to a 5V power supply, the third pin and the seventh pin of the analog electronic switch U1 are both electrically connected to the MCU main control circuit, and the fourth pin of the analog electronic switch U1 is grounded.

3. The control circuit of the eddy current displacement sensor according to claim 2, characterized in that: It also includes a capacitor C6, one end of which is electrically connected to the first pin of the analog electronic switch U1, the eighth pin of the analog electronic switch U1, one end of the first capacitor connected in parallel with the coil probe of the eddy current displacement sensor, and the fifth pin of the analog electronic switch U1, and one end of the capacitor C6 is connected to a 5V power supply, and the other end of the capacitor C6 is grounded.

4. The control circuit of the eddy current displacement sensor according to claim 1, characterized in that: It also includes a magnetically controlled switch, which is electrically connected to the MCU main control circuit.

5. The control circuit of the eddy current displacement sensor according to claim 1, characterized in that: It also includes an Internet of Things module, which is electrically connected to the MCU main control circuit.

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