Digital acquisition circuit of encoder sensor
By using dual operational amplifier circuits and resistance-capacitance low-pass filtering circuits in the digital acquisition circuit of the encoder sensor, the differential signal acquires the output signal of the encoder sensor, solving the problem of weak anti-interference ability in the prior art, and achieving higher signal accuracy and anti-interference performance.
Patent Information
- Application Number
- CN202421734571.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-22
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-07-22
AI Technical Summary
The digital acquisition circuit of existing encoder sensors has weak anti-interference ability, which can easily lead to counting errors.
The dual operational amplifier circuit and the resistive-capacitance low-pass filter circuit are used to acquire the output signal of the encoder sensor through differential signals to enhance the anti-interference performance of the signal.
It improves the signal transmission accuracy and anti-interference performance, and enhances the accuracy of signal acquisition.
Smart Images
Figure CN223024412U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of motor control, and particularly relates to a digital acquisition circuit for an encoder sensor.
Background Art
[0002] An encoder sensor is used to measure the rotational speed and rotation angle of a motor. After measurement, the encoder sensor outputs two digital signals, phase A and phase B. The rotation angle can be determined by pulse counting of phase A and phase B to judge the current position and speed of rotation, etc. The rotation direction can be judged by the phase difference between phase A and phase B. The outputs of phase A and phase B are similar, but there is a 90° phase difference between phase A and phase B. For example, when rotating forward, phase A leads phase B by 90° to output the phase first; when rotating backward, phase B leads phase A by 90° to output the phase first. The rotation direction can be judged by judging the phases of phase A and phase B. Therefore, the digital acquisition circuit of the encoder sensor requires a circuit with high precision and strong anti-interference ability to accurately judge the rotation angle and rotation direction of the motor by collecting the signals of the encoder sensor. In the prior art, the encoder acquisition factory uses single-ended pulse signal input and single-ended signal acquisition, with weak anti-interference ability and being easily interfered, resulting in counting errors.
[0003] Therefore, it is necessary to provide a digital acquisition circuit for an encoder sensor to solve the above technical problems.
Content of the Utility Model
[0004] The main purpose of the utility model is to provide a digital acquisition circuit for an encoder sensor, which improves the transmission accuracy, enhances the anti-interference performance of the signal, and improves the accuracy of signal acquisition.
[0005] The utility model realizes the above object through the following technical scheme: A digital acquisition circuit for an encoder sensor, which includes a dual operational amplifier circuit, a filtering circuit connected to the input end of the dual operational amplifier circuit, and a single-chip microcomputer processing circuit connected to the output end of the dual operational amplifier circuit;
[0006] The dual operational amplifier circuit includes a first operational amplifier for comparing and processing the phase A signal and a second operational amplifier for comparing and processing the phase B signal. The output ends of the first operational amplifier and the second operational amplifier are both connected to the single-chip microcomputer processing circuit. The single-chip microcomputer processing circuit collects the comparison results of the first operational amplifier and the second operational amplifier to determine the rotation angle and rotation direction of the motor;
[0007] The positive input end of the first operational amplifier is connected with a first filtering circuit, and the negative input end is connected with a second filtering circuit. The first filtering circuit and the second filtering circuit respectively receive the differential signals A+ and A- of phase A sent by the encoder sensor and filter out the noise in the differential signals;
[0008] The positive input terminal of the second operational amplifier is connected to a third filter circuit, and the negative input terminal is connected to a fourth filter circuit. The third filter circuit and the fourth filter circuit respectively receive the differential signals B+ and B- of the B phase emitted by the encoder sensor and filter out the noise in the differential signals.
[0009] Furthermore, the first filter circuit, the second filter circuit, the third filter circuit, and the fourth filter circuit are all resistor-capacitor low-pass filter circuits.
[0010] Furthermore, the first filter circuit, the second filter circuit, the third filter circuit, and the fourth filter circuit all include a resistor and a capacitor connected in series in sequence.
[0011] Furthermore, a first resistor is connected in parallel to the first filter circuit or the second filter circuit, and a second resistor is connected in parallel to the third filter circuit or the fourth filter circuit.
[0012] Furthermore, a first capacitor is connected to the power supply VCC terminal of the dual operational amplifier circuit.
[0013] Furthermore, a third resistor is connected in series to the output terminal of the first operational amplifier, and a fourth resistor is connected in series to the output terminal of the second operational amplifier.
[0014] Furthermore, a fifth resistor is connected in series to the output terminal of the first operational amplifier, and a sixth resistor is connected in series to the output terminal of the second operational amplifier. The fifth resistor is connected to the output terminal of the third resistor, and the sixth resistor is connected to the output terminal of the fourth resistor.
[0015] Furthermore, the single-chip microcomputer processing circuit includes an MCU chip processing unit connected to the output terminal of the dual operational amplifier circuit and a communication circuit connected to the MCU chip processing unit.
[0016] Compared with the prior art, the beneficial effects of the digital acquisition circuit of the encoder sensor of the present utility model are as follows: The digital acquisition circuit of the encoder sensor adopts a differential signal acquisition method. Since the amplitude of the differential signal is smaller than that of the single-ended signal, the signal sampling speed will be increased, thereby achieving higher data transmission accuracy; moreover, the differential signal can eliminate signal interference, enhance the anti-interference performance of the signal, and improve the accuracy of signal acquisition.
Description of the Drawings
[0017] Figure 1 It is a schematic structural diagram of the digital acquisition circuit of the encoder sensor according to the embodiment of the present utility model;
Detailed Embodiment
[0018] Due to the weak anti-interference ability of conventional single-ended signal acquisition, it is easily interfered, resulting in counting errors. Therefore, in this embodiment, differential signal acquisition is used to acquire the digital signal output by the encoder sensor. Accordingly, both the A-phase signal or the B-phase signal output by the encoder sensor is transmitted through two signal lines. The two signal lines of the A-phase signal are called the A+ signal and the A- signal, and the two signal lines of the B-phase signal are called the B+ signal and the B- signal. The comparator circuit determines whether the A-phase sent by the sending end is logic 0 or logic 1 by comparing the voltage difference between the A+ signal and the A- signal. At the same time, the comparator circuit also determines whether the B-phase sent by the sending end is logic 0 or logic 1 by comparing the voltage difference between the B+ and B-. After the comparison is completed, the signal receiving end acquires the phase and pulse number of the A-phase and the B-phase to determine the rotation direction and the rotation angle.
[0019] Please refer to Figure 1 , this embodiment is the digital acquisition circuit 100 of the encoder sensor. The digital acquisition circuit 100 of the encoder sensor includes a dual operational amplifier circuit 1, a filtering circuit 2 connected to the input end of the dual operational amplifier circuit 1, and a single-chip microcomputer processing circuit 3 connected to the output end of the dual operational amplifier circuit 1;
[0020] The dual operational amplifier circuit 1 includes a first operational amplifier 11 for comparing and processing the A-phase signal and a second operational amplifier 12 for comparing and processing the B-phase signal. The output ends of the first operational amplifier 11 and the second operational amplifier 12 are both connected to the single-chip microcomputer processing circuit 3. The single-chip microcomputer processing circuit 3 acquires the comparison results of the first operational amplifier 11 and the second operational amplifier 12 to determine the rotation angle and the rotation direction of the motor;
[0021] The positive input end of the first operational amplifier 11 is connected with a first filtering circuit 21, and the negative input end is connected with a second filtering circuit 22. The first filtering circuit 21 and the second filtering circuit 22 respectively receive the differential signals A+ and A- of the A-phase sent by the encoder sensor and filter out the noise in the differential signals;
[0022] The positive input end of the second operational amplifier 12 is connected with a third filtering circuit 23, and the negative input end is connected with a fourth filtering circuit 24. The third filtering circuit 23 and the fourth filtering circuit 24 respectively receive the differential signals B+ and B- of the B-phase sent by the encoder sensor and filter out the noise in the differential signals.
[0023] The first filtering circuit 21, the second filtering circuit 22, the third filtering circuit 23, and the fourth filtering circuit 24 are all resistor-capacitor low-pass filtering circuits.
[0024] The first filter circuit 21 includes a resistor R201 and a capacitor C200 connected in series with the resistor; the second filter circuit 22 includes a resistor R206 and a capacitor C201 connected in series with the resistor; the third filter circuit 23 includes a resistor R216 and a capacitor C205 connected in series with the resistor; the fourth filter circuit 24 includes a resistor R217 and a capacitor C206 connected in series with the resistor; one end of the capacitor C200 and one end of the capacitor C201 are grounded together, and one end of the capacitor C205 and one end of the capacitor C206 are grounded together.
[0025] Further, in order to filter out high-frequency noise in the circuit and make the signal output by the circuit purer and more stable, a first resistor R214 is connected in parallel to the first filter circuit 21 or the second filter circuit 22, and at the same time, a second resistor R226 is connected in parallel to the third filter circuit 23 or the fourth filter circuit 24; the output ends of the first resistor R214 and the second resistor R226 are both grounded to prevent the accumulation of static electricity and the generation of surge current.
[0026] In this embodiment:
[0027] The resistance values of the resistor R201, the resistor R206, the resistor R216, and the resistor R217 are the same and are 4K7Ω;
[0028] The capacitance values of the capacitor C200, the capacitor C201, the capacitor C205, and the capacitor C206 are the same and are 20pF;
[0029] The resistance value of the first resistor R214 is 10KΩ, and the resistance value of the second resistor R226 is 4K7Ω.
[0030] In other embodiments, the resistance values of the above resistors and the capacitance values of the capacitors can be determined according to the actual situation.
[0031] When the dual operational amplifier circuit 1 performs signal comparison processing, in order to suppress interference signals, a first capacitor C207 is connected to the power supply VCC terminal of the dual operational amplifier circuit 1. The first operational amplifier 11 and the second operational amplifier 12 are independent of each other. The first operational amplifier 11 determines whether the A phase sent by the sending end is logic 0 or logic 1 by the voltage difference between the differential signals A+ and A-. The second operational amplifier 12 determines whether the B phase sent by the sending end is logic 0 or logic 1 by the voltage difference between the differential signals B+ and B-. In order to prevent the oscillation phenomenon caused by the too-fast change of the signals at the output terminals of the first operational amplifier 11 and the second operational amplifier 12, therefore, a third resistor R228 is connected in series at the output terminal of the first operational amplifier 11, and a fourth resistor R227 is connected in series at the output terminal of the second operational amplifier 12; in order to prevent the current input to the circuit from being too large and damaging the first operational amplifier 11 and the second operational amplifier 12, a fifth resistor R261 is connected in series at the output terminal of the first operational amplifier 11, and a sixth resistor R260 is connected in series at the output terminal of the second operational amplifier 12; the fifth resistor R261 is connected to the output terminal of the third resistor R228, and the sixth resistor R260 is connected to the output terminal of the fourth resistor R227.
[0032] After the first operational amplifier 11 finishes the comparison, the A-phase comparison result MCIA_IN is sent out at the output terminal. After the second operational amplifier 12 finishes the comparison, the B-phase comparison result MCIB_IN is sent out at the output terminal. The comparison result MCIA_IN includes the phase and the number of pulses of the A phase. The comparison result MCIB_IN includes the phase and the number of pulses of the B phase. The single-chip microcomputer processing circuit 3 respectively collects the output comparison results MCIA_IN and MCIB_IN. The rotation angle of the motor can be determined by the number of pulses of the A phase and the B phase. The rotation direction of the motor is determined by comparing the phase of the A phase and the phase of the B phase. When the A phase leads the B phase by 90° and the phase output is performed first, it is a forward rotation. When the B phase leads the A phase by 90° and the phase output is performed first, it is a reverse rotation.
[0033] The single-chip microcomputer processing circuit 3 includes an MCU chip processing unit connected to the output terminal of the dual operational amplifier circuit 1 and a communication circuit connected to the MCU chip processing unit. The communication circuit is an RS232 interface.
[0034] When applying the digital acquisition circuit 100 of the encoder sensor provided by this solution, the input ends of the first filtering circuit 21 and the second filtering circuit 22 respectively receive the differential signals A+ and A- emitted by the encoder sensor, and the input ends of the third filtering circuit 23 and the fourth filtering circuit 24 respectively receive the differential signals B+ and B-. After filtering to eliminate interference, the differential signals A+ and A- are input to the input end of the first operational amplifier 11 to form a comparator circuit. The first operational amplifier 11 determines whether the A phase sent by the sending end is logic 0 or logic 1 by the voltage difference between the differential signals A+ and A-. At the same time, the differential signals B+ and B- are input to the input end of the second operational amplifier 12 to form a comparator circuit. The second operational amplifier 12 determines whether the B phase sent by the sending end is logic 0 or logic 1 by the voltage difference between the differential signals B+ and B-. After the judgment is completed, the output end of the first operational amplifier 11 emits the A-phase comparison result MCIA_IN after the comparison is completed, and the output end of the second operational amplifier 12 emits the B-phase comparison result MCIB_IN after the comparison is completed. The single-chip microcomputer processing circuit 3 respectively collects the output comparison results MCIA_IN and MCIB_IN, and can determine the rotation angle of the motor through the number of pulses of the A phase and the B phase, and determine the rotation direction of the motor by comparing the phase of the A phase and the phase of the B phase. When the A phase leads the B phase by 90° and the phase output is carried out first, it is a forward rotation, and when the B phase leads the A phase by 90° and the phase output is carried out first, it is a reverse rotation.
[0035] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.
Claims
1. The digital acquisition circuit of the encoder sensor is characterized by: It comprises a dual operational amplifier circuit (1), a filter circuit (2) connected to the input end of the dual operational amplifier circuit (1), and a single-chip processing circuit (3) connected to the output end of the dual operational amplifier circuit (1); The dual operational amplifier circuit (1) comprises a first operational amplifier (11) for comparing and processing an A-phase signal and a second operational amplifier (12) for comparing and processing a B-phase signal, the output ends of the first operational amplifier (11) and the second operational amplifier (12) are both connected to the single-chip processing circuit (3), and the single-chip processing circuit (3) collects a comparison result between the first operational amplifier (11) and the second operational amplifier (12) to determine a rotation angle and a rotation direction of the motor; The positive input end of the first operational amplifier (11) is connected to a first filter circuit (21), and the negative input end is connected to a second filter circuit (22), the first filter circuit (21) and the second filter circuit (22) respectively receive the differential signals A+ and A- of the A phase emitted by the encoder sensor and filter out noise in the differential signals; The positive input terminal of the second operational amplifier (12) is connected to a third filter circuit (23), and the negative input terminal is connected to a fourth filter circuit (24). The third filter circuit (23) and the fourth filter circuit (24) respectively receive the B-phase differential signals B+ and B- emitted by the encoder sensor and filter out noise in the differential signals.
2. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: The first filter circuit (21), the second filter circuit (22), the third filter circuit (23) and the fourth filter circuit (24) are all resistance-capacitance low-pass filter circuits.
3. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: The first filter circuit (21), the second filter circuit (22), the third filter circuit (23) and the fourth filter circuit (24) all include resistors (R201, R206, R216, R217) and capacitors (C200, C201, C205, C206) connected in series in sequence.
4. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: A first resistor (R214) is connected in parallel to the first filter circuit (21) or the second filter circuit (22), and a second resistor (R226) is connected in parallel to the third filter circuit (23) or the fourth filter circuit (24).
5. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: The power supply VCC terminal of the dual operational amplifier circuit (1) is connected to a first capacitor (C207).
6. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: A third resistor (R228) is connected in series to the output end of the first operational amplifier (11), and a fourth resistor (R227) is connected in series to the output end of the second operational amplifier (12).
7. The digital acquisition circuit of the encoder sensor according to claim 6, characterized in that: A fifth resistor (R261) is connected in series to the output end of the first operational amplifier (11), a sixth resistor (R260) is connected in series to the output end of the second operational amplifier (12), the fifth resistor (R261) is connected to the output end of the third resistor (R228), and the sixth resistor (R260) is connected to the output end of the fourth resistor (R227).
8. The digital acquisition circuit of the encoder sensor according to claim 1, characterized in that: The single chip microcomputer processing circuit (3) comprises an MCU chip processing unit connected to the output end of the dual operational amplifier circuit (1) and a communication circuit connected to the MCU chip processing unit.