A speed measuring circuit and device

Abstract

This utility model discloses a speed measuring circuit and an electronic device with such a circuit. The speed measuring circuit includes a power supply, a signal conversion chip, a control chip, a first capacitor, a relay, and a photoelectric module. The photoelectric module includes a light-emitting end and a light-receiving end. The output end of the signal conversion chip is connected to the detection end of the control chip. The input end of the signal conversion chip is connected to one end of the first capacitor. The other end of the first capacitor is connected to the common terminal of the relay. The normally closed terminal of the relay is connected to the calibration end of the control chip. The normally open terminal of the relay is connected to one end of the light-receiving end. The control end of the relay is connected to the output end of the control chip. The power supply is connected to the power supply terminals of the signal conversion chip, the other end of the light-receiving end, the light-emitting end, and the control chip. This utility model can measure the rotational speed of rotating machinery without obtaining the voltage output from the motor.

Description

Technical Field

[0001] This utility model relates to the field of speed measuring circuits, and in particular to a speed measuring circuit and device. Background Technology

[0002] In engineering testing technology, measuring the rotational speed of rotating machinery is a crucial task. Besides providing control and monitoring data for maintaining the machinery's operating speed, it is also used to assist in vibration detection and analysis of the causes of vibration. Because the amplitude of the motor's output voltage varies with the speed of the measured machinery, the amplitude range of its output electrical signal voltage varies considerably. Furthermore, the signal is analog, requiring an A / D conversion circuit when interfaced with computer equipment, and is susceptible to external interference. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a speed measuring circuit that can measure the rotational speed of rotating machinery without acquiring the voltage output from the motor.

[0004] This invention also proposes an electronic device having the aforementioned speed measuring circuit.

[0005] A speed measuring circuit according to a first aspect of the present invention includes: a power supply, a signal conversion chip, a control chip, a first capacitor, a relay, and a photoelectric module. The photoelectric module includes a light-emitting end and a light-receiving end. The output end of the signal conversion chip is connected to the detection end of the control chip. The input end of the signal conversion chip is connected to one end of the first capacitor. The other end of the first capacitor is connected to the common terminal of the relay. The normally closed terminal of the relay is connected to the calibration terminal of the control chip. The normally open terminal of the relay is connected to one end of the light-receiving end. The control terminal of the relay is connected to the output end of the control chip. The power supply is connected to the power supply terminal of the signal conversion chip, the other end of the light-receiving end, the light-emitting end, and the power supply terminal of the control chip.

[0006] The speed measuring circuit according to this embodiment of the present invention has at least the following beneficial effects: When the output terminal of the control chip sends a low-level signal to the control terminal of the relay, the normally closed terminal of the relay is connected to the common terminal of the relay, and the input terminal of the signal conversion chip is connected to the calibration terminal of the control chip through the first capacitor. At this time, both the input and output terminals of the signal conversion chip are connected to the control chip, and the calibration terminal of the control chip can send a frequency signal to the input terminal of the signal conversion chip, and calibrate the control chip according to the signal output from the output terminal of the signal conversion chip. When the output of the control chip sends a high-level signal to the control terminal of the relay, the normally open terminal of the relay is connected to the common terminal of the relay. The input terminal of the signal conversion chip is connected to the light-receiving terminal of the photoelectric module through the first capacitor. The light-receiving terminal and the light-emitting terminal of the photoelectric module are respectively set on both sides of the rotating end of the device under test. Since there is a gap between the fan blades of the device under test, when the fan blades rotate between the light-receiving terminal and the light-emitting terminal of the photoelectric module, the light of the light-emitting terminal is blocked by the fan blades, and the light-receiving terminal stops conducting. When the light of the light-emitting terminal is not blocked by the fan blades, the light-receiving terminal conducts, thereby forming a frequency signal that is sent to the signal conversion chip. The signal conversion chip converts the frequency signal into a voltage signal and outputs it to the detection terminal of the control chip, thereby enabling the measurement of the rotational speed of the rotating machinery without acquiring the voltage output of the motor.

[0007] According to some embodiments of the present invention, the speed measuring circuit further includes a first resistor, a first transistor, and a second resistor. The collector of the first transistor is connected to the power supply, the base of the first transistor is connected to the output terminal of the control chip through the first resistor, and the emitter of the first transistor is connected to the control terminal of the relay through the second resistor.

[0008] According to some embodiments of the present invention, the speed measuring circuit further includes a third resistor and a second capacitor. The detection terminal of the control chip is connected to the first terminal of the third resistor and the first terminal of the second capacitor, respectively. The output terminal of the signal conversion chip is connected to the second terminal of the third resistor, the second terminal of the second capacitor, and the ground terminal, respectively.

[0009] According to some embodiments of the present invention, the speed measuring circuit further includes a fourth resistor and an adjustable resistor, the fourth resistor and the adjustable resistor being connected in series to form a first branch, one end of the first branch being connected to the reference terminal of the signal conversion chip.

[0010] According to some embodiments of the present invention, the speed measuring circuit further includes a fifth resistor and a sixth resistor. The comparison terminal of the signal conversion chip is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor, respectively. The second terminal of the fifth resistor is connected to the power supply, and the second terminal of the sixth resistor is grounded.

[0011] According to some embodiments of the present invention, the speed measuring circuit further includes a seventh resistor, the first end of which is connected to the power supply, and the second end of which is connected to the connection point between the input terminal of the signal conversion chip and the first capacitor.

[0012] According to some embodiments of the present invention, the speed measuring circuit further includes an eighth resistor and a third capacitor. The first end of the eighth resistor is connected to the power supply, the second end of the eighth resistor is connected to the filter input terminal of the signal conversion chip and the first end of the third capacitor, and the second end of the third capacitor is grounded.

[0013] According to some embodiments of the present invention, the speed measuring circuit further includes a ninth resistor, which is connected between the positive terminal of the light-emitting end and the power supply, and the negative terminal of the light-emitting end is grounded.

[0014] According to some embodiments of the present invention, the speed measuring circuit further includes a tenth resistor, one end of the light-receiving end is connected to the power supply, the other end of the light-receiving end is connected to the first end of the tenth resistor and the normally open end of the relay respectively, and the second end of the tenth resistor is grounded.

[0015] An electronic device according to a second aspect of the present invention includes the speed measuring circuit described in the first aspect embodiment.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 This is a circuit diagram of the speed measuring circuit according to an embodiment of the present invention. Detailed Implementation

[0019] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0020] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0021] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0023] Reference Figure 1 , Figure 1 The present invention provides a circuit diagram of a speed measuring circuit, which includes a power supply VCC, a signal conversion chip U1, a control chip, a first capacitor C1, a relay RLY1, and a photoelectric module U2. The photoelectric module U2 includes a light-emitting end and a light-receiving end. The output terminal IOUT of the signal conversion chip U1 is connected to the detection terminal ADC of the control chip. The input terminal THRESH of the signal conversion chip U1 is connected to the first terminal of the first capacitor C1. The second terminal of the first capacitor C1 is connected to the common terminal of the relay RLY1. The normally closed terminal of the relay RLY1 is connected to the calibration terminal PN1 of the control chip. The normally open terminal of the relay RLY1 is connected to one end of the light-receiving end. The control terminal of the relay RLY1 is connected to the output terminal PN2 of the control chip. The power supply VCC is connected to the power supply terminal VS of the signal conversion chip U1, the other end of the light-receiving end, the light-emitting end, and the power supply terminal of the control chip.

[0024] It should be noted that when the output terminal PN2 of the control chip sends a low-level signal to the control terminal of the relay RLY1, the normally closed terminal of the relay RLY1 is connected to the common terminal of the relay RLY1, and the input terminal THRESH of the signal conversion chip U1 is connected to the calibration terminal PN1 of the control chip through the first capacitor C1. At this time, both the input terminal THRESH and the output terminal IOUT of the signal conversion chip U1 are connected to the control chip. The calibration terminal PN1 of the control chip can send a frequency signal to the input terminal THRESH of the signal conversion chip U1, and calibrate the control chip according to the signal output from the output terminal IOUT of the signal conversion chip U1. When the output terminal PN2 of the control chip sends a high-level signal to the control terminal of the relay RLY1, the normally open terminal of the relay RLY1 is connected to the common terminal of the relay RLY1, and the input terminal THRESH of the signal conversion chip U1 is connected to the light-receiving terminal of the photoelectric module U2 through the first capacitor C1. The light-receiving end and the light-emitting end of the photoelectric module U2 are respectively located on both sides of the rotating end of the device under test. Because there is a gap between the fan blades of the device under test, when the fan blades rotate between the light-receiving end and the light-emitting end of the photoelectric module U2, the light from the light-emitting end is blocked by the fan blades, and the light-receiving end stops conducting; when the light from the light-emitting end is not blocked by the fan blades, the light-receiving end conducts. The conduction and cutoff of the light-receiving end causes the first capacitor C1 to switch between charging and discharging states, thereby generating a frequency signal that is sent to the input terminal THRESH of the signal conversion chip U1. The signal conversion chip U1 converts the frequency signal into a voltage signal and outputs it to the detection terminal ADC of the control chip, thus enabling the measurement of the rotational speed of the rotating machinery without acquiring the voltage output from the motor.

[0025] Specifically, when the control chip's calibration terminal PN1 sends a 1kHz signal to the input terminal THRESH of the signal conversion chip U1, the output terminal IOUT of the signal conversion chip U1 outputs a first voltage value. The frequency signal corresponding to this first voltage value is 1kHz. During speed detection, if the second voltage value output by the output terminal IOUT of the signal conversion chip U1 is twice the first voltage value, the control chip can calculate that the frequency signal received by the input terminal THRESH of the signal conversion chip U1 is 2kHz.

[0026] Specifically, the signal conversion chip U1 can be an LM331 chip.

[0027] It should be noted that the speed measuring circuit also includes a first resistor R1, a first transistor Q1, and a second resistor R2. The collector of the first transistor Q1 is connected to the power supply VCC, the base of the first transistor Q1 is connected to the output terminal PN2 of the control chip through the first resistor R1, and the emitter of the first transistor Q1 is connected to the control terminal of the relay RLY1 through the second resistor R2.

[0028] Specifically, when the output terminal PN2 of the control chip outputs a low level, the first transistor Q1 is cut off, the control terminal of relay RLY1 is de-energized, and the common terminal of relay RLY1 is connected to the normally closed terminal; when the output terminal PN2 of the control chip outputs a high level, the first transistor Q1 is turned on, the control terminal of relay RLY1 is energized, and the common terminal of relay RLY1 is connected to the normally open terminal.

[0029] It should be noted that the speed measuring circuit also includes a third resistor R3 and a second capacitor C2. The detection terminal ADC of the control chip is connected to the first terminal of the third resistor R3 and the first terminal of the second capacitor C2, respectively. The output terminal IOUT of the signal conversion chip U1 is connected to the second terminal of the third resistor R3, the second terminal of the second capacitor C2, and the ground terminal, respectively.

[0030] It should be noted that the speed measuring circuit also includes a fourth resistor R4 and an adjustable resistor R11. The fourth resistor R4 and the adjustable resistor R11 are connected in series to form the first branch. One end of the first branch is connected to the reference terminal IREF of the signal conversion chip U1.

[0031] It should be noted that the speed measuring circuit also includes a fifth resistor R5 and a sixth resistor R6. The comparator terminal COMPIN of the signal conversion chip U1 is connected to the first terminal of the fifth resistor R5 and the first terminal of the sixth resistor R6, respectively. The second terminal of the fifth resistor R5 is connected to the power supply VCC, and the second terminal of the sixth resistor R6 is grounded.

[0032] It should be noted that the speed measuring circuit also includes a seventh resistor R7. The first end of the seventh resistor R7 is connected to the power supply VCC, and the second end of the seventh resistor R7 is connected to the connection point between the input terminal THRESH of the signal conversion chip U1 and the first capacitor C1.

[0033] It should be noted that the speed measuring circuit also includes an eighth resistor R8 and a third capacitor C3. The first end of the eighth resistor R8 is connected to the power supply VCC, and the second end of the eighth resistor R8 is connected to the filter input terminal RC of the signal conversion chip U1 and the first end of the third capacitor C3, respectively. The second end of the third capacitor C3 is grounded.

[0034] It should be noted that the speed measuring circuit also includes a ninth resistor R9, which is connected between the positive terminal of the light-emitting end and the power supply VCC, while the negative terminal of the light-emitting end is grounded.

[0035] It should be noted that the speed measuring circuit also includes a tenth resistor R10. One end of the light receiving end is connected to the power supply VCC, and the other end of the light receiving end is connected to the first end of the tenth resistor R10 and the normally open terminal of the relay RLY1. The second end of the tenth resistor R10 is grounded.

[0036] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A speed measurement circuit, characterized by include: The system comprises a power supply, a signal conversion chip, a control chip, a first capacitor, a relay, and a photoelectric module. The photoelectric module includes a light-emitting end and a light-receiving end. The output end of the signal conversion chip is connected to the detection end of the control chip. The input end of the signal conversion chip is connected to one end of the first capacitor. The other end of the first capacitor is connected to the common terminal of the relay. The normally closed terminal of the relay is connected to the calibration terminal of the control chip. The normally open terminal of the relay is connected to one end of the light-receiving end. The control terminal of the relay is connected to the output end of the control chip. The power supply is connected to the power supply terminal of the signal conversion chip, the other end of the light-receiving end, the light-emitting end, and the power supply terminal of the control chip.

2. The speed measurement circuit of claim 1, wherein The speed measuring circuit also includes a first resistor, a first transistor, and a second resistor. The collector of the first transistor is connected to the power supply, the base of the first transistor is connected to the output terminal of the control chip through the first resistor, and the emitter of the first transistor is connected to the control terminal of the relay through the second resistor.

3. The speed measurement circuit of claim 1, wherein The speed measuring circuit also includes a third resistor and a second capacitor. The detection terminal of the control chip is connected to the first terminal of the third resistor and the first terminal of the second capacitor, respectively. The output terminal of the signal conversion chip is connected to the second terminal of the third resistor, the second terminal of the second capacitor, and the ground terminal, respectively.

4. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes a fourth resistor and an adjustable resistor. The fourth resistor and the adjustable resistor are connected in series to form a first branch. One end of the first branch is connected to the reference terminal of the signal conversion chip.

5. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes a fifth resistor and a sixth resistor. The comparison terminal of the signal conversion chip is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor, respectively. The second terminal of the fifth resistor is connected to the power supply, and the second terminal of the sixth resistor is grounded.

6. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes a seventh resistor, the first end of which is connected to the power supply, and the second end of which is connected to the connection point between the input terminal of the signal conversion chip and the first capacitor.

7. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes an eighth resistor and a third capacitor. The first end of the eighth resistor is connected to the power supply, the second end of the eighth resistor is connected to the filter input terminal of the signal conversion chip and the first end of the third capacitor, and the second end of the third capacitor is grounded.

8. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes a ninth resistor, which is connected between the positive terminal of the light-emitting end and the power supply, and the negative terminal of the light-emitting end is grounded.

9. The speed measuring circuit according to claim 1, characterized in that, The speed measuring circuit also includes a tenth resistor. One end of the light-receiving end is connected to the power supply, and the other end of the light-receiving end is connected to the first end of the tenth resistor and the normally open terminal of the relay, respectively. The second end of the tenth resistor is grounded.

10. An electronic device, characterized in that, Includes the speed measuring circuit as described in any one of claims 1 to 9.

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