A new analog code disc testing system

Abstract

The utility model discloses a novel simulation code disc test system relates to test field, and this novel simulation code disc test system includes: power supply circuit is used for supplying working voltage, RS485 communication circuit is used for building the communication of host computer MCU circuit and host computer, infrared signal input circuit is used for receiving external IR input signal PWM IN, and after the comparator processing, compared with prior art, the beneficial effects of the utility model are: the utility model through host computer flexible setting speed, signal frequency ratio and multiple output voltage (including positive and negative voltage), realize a piece of general simulation board adapts the quick test of multiple motor control board, not only avoid the human consumption and hardware loss of frequent dismounting motor, more with the full electronization signal generation ensures the high accuracy, high repeatability and safety of testing process, fundamentally solves the low efficiency, the operation of traditional test method is complicated, and the pain point of poor adaptability.

Description

Technical Field

[0001] This utility model relates to the field of testing, specifically a novel analog encoder testing system. Background Technology

[0002] Currently, the traditional testing method for motor products is one control board per motor. In the mass production FCT (Functional Circuit Test) process, the traditional testing method is not only cumbersome to operate, requiring repeated disassembly and assembly of the motor, but also requires each test board to wait for the motor to start and stop and read encoder or Hall feedback data, which greatly increases the testing time and leads to low production efficiency, and needs to be improved. Utility Model Content

[0003] The purpose of this invention is to provide a novel analog encoder testing system to solve the problems mentioned in the background section.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A novel analog encoder testing system includes:

[0006] Power supply circuit, used to supply operating voltage;

[0007] The RS485 communication circuit is used to establish communication between the main control MCU circuit and the host computer.

[0008] The infrared signal input circuit is used to receive the external IR input signal PWM_IN. After being processed by the comparator, it outputs a 3.3V IR output signal PWM_OUT to the main control MCU circuit (the main control MCU circuit performs frequency multiplication on PWM_OUT and outputs an R signal with an amplitude of 3.3V, and then outputs an R signal with an amplitude of 5V to the board under test through the output level conversion circuit).

[0009] The main control MCU circuit is used to generate A, B, Z, U, V, W, R signals with an amplitude of 3.3V to the output level conversion circuit;

[0010] The output level conversion circuit converts the 3.3V A, B, Z, U, V, W, R signals into 5V A1, B1, Z1, U1, V1, W1, R1 signals. The 5V Z1, U1, V1, W1, R1 signals are then output to the board under test. The 5V A1 and B1 signals are output to the board under test via the AB positive and negative voltage output circuit or the AB output voltage selection circuit.

[0011] The AB positive and negative voltage output circuit is used to convert the A1 and B1 signals into positive and negative PWM waves and output them to the board under test.

[0012] The AB output voltage selection circuit is used to adjust the amplitude of the 5V A1 and B1 signals before outputting them to the board under test.

[0013] The power supply circuit is connected to the RS485 communication circuit, the infrared signal input circuit, the main control MCU circuit, the output level conversion circuit, and the AB positive and negative voltage output circuit. The main control MCU circuit is connected to the RS485 communication circuit, the infrared signal input circuit, and the output level conversion circuit. The output level conversion circuit is connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit.

[0014] As a further improvement of this utility model, the power supply circuit includes:

[0015] The power supply reverse connection protection filter circuit is used to receive external power input, output filtered VIN voltage, and provide reverse connection protection.

[0016] A switching power supply sub-circuit is used to obtain 5V and -2.5V / -1.65V / -0.55V voltages based on VIN voltage;

[0017] The MCU power supply circuit is used to output a 3.3V voltage based on a 5V voltage to power the main control MCU circuit.

[0018] The output of the reverse polarity protection filter sub-circuit is connected to the input of the switching power supply sub-circuit, and the output of the switching power supply sub-circuit is connected to the input of the MCU power supply circuit.

[0019] As a further embodiment of this utility model: the RS485 communication circuit includes chip IC1, model ST3485EBDR. Pin 1 of chip IC1 is connected to one end of resistor R71 and one end of resistor R66. The other end of resistor R71 is connected to the main control MCU circuit, and the other end of resistor R66 is connected to a 3.3V voltage. Pins 2 and 3 of chip IC1 are connected to one end of resistor R74 and one end of resistor R80. The other end of resistor R74 is connected to the main control MCU circuit, and the other end of resistor R80 is grounded. Pin 4 of chip IC1 is connected to one end of resistor R76, and the other end of resistor R76 is connected to the main control MCU circuit. Pin 6 of chip IC1 is connected to the second end of interface CN4 in sequence through resistors R75 and R81. Pin 7 of chip IC1 is connected to the first end of interface CN4 in sequence through resistors R72 and R67.

[0020] As a further embodiment of this invention: the infrared signal input circuit includes an amplifier U6. The non-inverting input of the amplifier U6 is connected to the negative terminal of the Zener diode Z10, one end of the resistor R78, one end of the capacitor C28, and one end of the resistor R65. The other end of the capacitor C28 is grounded. The positive terminal of the Zener diode Z10 is grounded through the resistor R82. The other end of the resistor R78 is connected to the external IR input signal PWM_IN. The inverting input of the amplifier U6 is connected to one end of the resistor R64 and one end of the resistor R68. The other end of the resistor R68 is grounded. The other end of the resistor R64 is connected to the other end of the resistor R65 and a 5V voltage. The output terminal of the amplifier U6 is connected to one end of the resistor R69 and one end of the resistor R73. The other end of the resistor R69 is connected to a 3.3V voltage. The other end of the resistor R73 outputs the signal PWM_OUT.

[0021] As a further improvement of this utility model: the main control MCU circuit includes a chip U7, the model of which is STM32G474CBT6. Pins 31, 32, and 33 of the chip U7 are connected to the RS485 communication circuit, pin 25 of the chip U7 is connected to the infrared signal input circuit, and pins 8, 9, 10, 13, 15, 22, and 40 of the chip U7 are connected to the output level conversion circuit.

[0022] As a further improvement of this utility model: the output level conversion circuit includes a chip U8, the model of which is SN74LVC8T245QPWRQ1. Pins 3 to 9 of the chip U8 are connected to the main control MCU circuit, pins 20 and 21 of the chip U8 are connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit, and pins 15 to 19 of the chip U8 are connected to the board under test.

[0023] As a further embodiment of this utility model: the AB positive and negative voltage output circuit includes two positive and negative voltage output sub-circuits, which respectively process the A1 signal and the B1 signal; the positive and negative voltage output sub-circuit includes amplifier U5, transistor Q6, and transistor Q10. The non-inverting input of amplifier U5 is connected to the A1 signal through resistor R59, and the inverting input of amplifier U5 is connected to one end of resistor R46 and one end of resistor R52. The other end of resistor R52 is grounded, and the other end of resistor R46 is connected to a 5V voltage. The output terminal of amplifier U5 is connected to one end of resistor R57 and resistor R28. One end of resistor R28, one end of resistor R29, one end of resistor R35, one end of resistor R41, the other end of resistor R28 is connected to 5V voltage, the other end of resistor R29 is grounded, the other end of resistor R35 is connected to the collector of transistor Q6, the emitter of transistor Q6 is grounded, the base of transistor Q6 is connected to the main control MCU circuit through resistor R36, the other end of resistor R41 is connected to the collector of transistor Q10, the emitter of transistor Q10 is grounded, the base of transistor Q10 is connected to the main control MCU circuit through resistor R47, and the other end of resistor R57 is connected to the board under test through interface J1.

[0024] As a further embodiment of this invention: the AB output voltage selection circuit includes two output voltage selection sub-circuits, which respectively process the A1 signal and the B1 signal; the output voltage selection sub-circuit includes a resistor R31, one end of which is connected to the A1 signal, and the other end of which is connected to one end of a resistor R33 and one end of a resistor R55. The other end of the resistor R33 is connected to the collector of transistor Q11, the emitter of transistor Q11 is grounded, the base of transistor Q11 is connected to one end of a resistor R39, the other end of which is connected to the main control MCU circuit, the other end of the resistor R55 is connected to the collector of transistor Q13, the emitter of transistor Q13 is grounded, the base of transistor Q13 is connected to one end of a resistor R61, and the other end of the resistor R61 is connected to the main control MCU circuit.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model realizes rapid testing of a universal analog board that can be adapted to multiple motor control boards by flexibly setting the speed, signal frequency ratio and multiple output voltages (including positive and negative voltages) through the host computer. It not only avoids the manpower consumption and hardware wear and tear of frequent motor disassembly, but also ensures high precision, high repeatability and safety of the testing process with fully electronic signal generation. It fundamentally solves the pain points of low efficiency, cumbersome operation and poor adaptability of traditional testing methods. Attached Figure Description

[0026] Figure 1 The circuit diagram of the power supply anti-reverse connection filter circuit.

[0027] Figure 2This is the circuit diagram of the switching power supply sub-circuit.

[0028] Figure 3 Circuit diagram of the electronic circuitry for the MCU.

[0029] Figure 4 This is a circuit diagram of an RS485 communication circuit.

[0030] Figure 5 This is a circuit diagram of the infrared signal input circuit.

[0031] Figure 6 This is the circuit diagram of the main control MCU circuit.

[0032] Figure 7 This is a circuit diagram of the output level conversion circuit.

[0033] Figure 8 This is the circuit diagram for the AB positive and negative voltage output circuit.

[0034] Figure 9 The circuit diagram for the AB output voltage selection circuit. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0036] Please see Figures 1 to 9 A novel analog encoder testing system includes:

[0037] Power supply circuit, used to supply operating voltage;

[0038] The RS485 communication circuit is used to establish communication between the main control MCU circuit and the host computer.

[0039] The infrared signal input circuit is used to receive the external IR input signal PWM_IN. After being processed by the comparator, it outputs a 3.3V IR output signal PWM_OUT to the main control MCU circuit (the main control MCU circuit performs frequency multiplication on PWM_OUT and outputs an R signal with an amplitude of 3.3V, and then outputs an R signal with an amplitude of 5V to the board under test through the output level conversion circuit).

[0040] The main control MCU circuit is used to generate A, B, Z, U, V, W, R signals with an amplitude of 3.3V to the output level conversion circuit;

[0041] The output level conversion circuit converts the 3.3V A, B, Z, U, V, W, R signals into 5V A1, B1, Z1, U1, V1, W1, R1 signals. The 5V Z1, U1, V1, W1, R1 signals are then output to the board under test. The 5V A1 and B1 signals are output to the board under test via the AB positive and negative voltage output circuit or the AB output voltage selection circuit.

[0042] The AB positive and negative voltage output circuit is used to convert the A1 and B1 signals into positive and negative PWM waves and output them to the board under test.

[0043] The AB output voltage selection circuit is used to adjust the amplitude of the 5V A1 and B1 signals before outputting them to the board under test.

[0044] The power supply circuit is connected to the RS485 communication circuit, the infrared signal input circuit, the main control MCU circuit, the output level conversion circuit, and the AB positive and negative voltage output circuit. The main control MCU circuit is connected to the RS485 communication circuit, the infrared signal input circuit, and the output level conversion circuit. The output level conversion circuit is connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit.

[0045] In a specific embodiment: the host computer inputs control signals, and the analog board (a novel analog encoder testing system) outputs corresponding feedback signals such as A, B, Z, U, V, W, and IR (represented by the R signal in the attached diagram) to the board under test. The analog board and the host computer exchange information via an RS485 communication circuit, or alternatively via Modbus, Modbus RTU, or CRC16 communication. The motor speed is transmitted from the host computer to the main control MCU circuit of the analog board via the RS485 communication circuit. The frequency multiples of the A and B signals relative to the U, V, and W signals are set by the host computer, and the output signal voltage is set to an adjustable voltage signal to match different voltage models. After level conversion, a high-speed comparator outputs positive and negative voltages AB, which are then fed back to the board under test, thereby realizing the function of the analog encoder.

[0046] Work process:

[0047] 1. During the testing of the motor control board, a resistor and an inductor are connected in series to simulate the motor windings. This simulation board is used to simulate the motor feedback signal.

[0048] 2. Power the analog board's power supply circuit with a 3-18V power supply.

[0049] 3. The simulation board and the host computer exchange information. The motor speed is sent from the host computer to the simulation board via the communication port, in rpm (revolutions per minute), with a speed range of 20-10000 rpm. An external infrared input (IR) and an EN port are also included. The EN port is used to control whether the system is operating normally.

[0050] 4. The analog board outputs seven square wave signals from the motor encoder: A, B, Z, U, V, W, and IR. The IR signal is input externally and then multiplied for output. The periods of the U, V, and W signals are determined by the motor speed, with one cycle occurring per motor revolution (defaulting to one pair of poles). The U, V, and W signals are 120° out of phase. The A and B signals (output PWM voltage adjustable, offering six PWM waveforms: 5V, 3.3V, 2.5V, ±2.5V, ±1.65V, and ±0.55V) have their frequency multiples relative to the U, V, and W signals set by the host computer and sent to the analog board via communication. The A and B signals are 90° out of phase. The Z signal is one pulse per revolution, with the same pulse width as the A or B signal, and its rising edge is aligned with the W signal.

[0051] 5. If the motor control board can drive normally during communication, it means that the control board is normal.

[0052] In this embodiment: Please refer to Figures 1 to 3 The power supply circuit includes:

[0053] The power supply reverse connection protection filter circuit is used to receive external power input, output filtered VIN voltage, and provide reverse connection protection.

[0054] A switching power supply sub-circuit is used to obtain 5V and -2.5V / -1.65V / -0.55V voltages based on VIN voltage;

[0055] The MCU power supply circuit is used to output a 3.3V voltage based on a 5V voltage to power the main control MCU circuit.

[0056] The output of the reverse polarity protection filter sub-circuit is connected to the input of the switching power supply sub-circuit, and the output of the switching power supply sub-circuit is connected to the input of the MCU power supply circuit.

[0057] Please see Figure 1The power supply reverse connection protection filter circuit connects to a DC power supply (2-18V wide voltage input) via interface CN1. The input passes through fuse FUSE1, then through filter capacitors C6, C7, and C8 to the VIN output. As shown in the diagram, the first and second terminals of interface CN1 are connected to the drain of MOSFET M1 and fuse FUSE1, respectively. Diode D1, resistor R14, resistor R15, diode D2, and MOSFET M1 form the reverse connection protection circuit. When the positive and negative inputs are correct, the voltage is divided by diode D1 and resistors R14 and R15. The circuit returns to the negative terminal through the body diode. When the input voltage meets the minimum turn-on voltage, MOSFET M1 conducts to provide normal power supply. If the voltage is accidentally reversed, the presence of MOSFET M1 prevents the power supply from forming a circuit, thus preventing reverse connection. FUSE1 is a slow-blow surface-mount fuse, which serves as overcurrent protection to prevent short circuits at the downstream end. C6, C7, C8, and C10 are filter capacitors, mainly used to filter the input voltage into a smoother DC voltage. This circuit enables wide input voltage and reverse connection protection for power supply safety.

[0058] Please see Figure 2 The switching power supply sub-circuit takes an input voltage VIN, which, after passing through the BUCK-BOOST chip U1, outputs 5V to power subsequent circuits. U1, R1, R2, R3, R8, R9, C1, C2, C3, C4, C5, and L1 form the BUCK-BOOST step-up / step-down circuit, outputting 5V. Chip U1 is a TPS63070RNMR power chip; capacitor C1 is a bypass capacitor for the internal voltage regulator; resistor R1 is the operating mode selection resistor, connecting it to a high level activates energy-saving mode; resistors R1 and R2 are voltage divider resistors for the feedback voltage, allowing different output voltages to be set by adjusting their ratio; capacitor C2 is the input decoupling capacitor; resistor R3 is the Power Good indicator pin, but this function is not used, so it is connected to the 5V output. Inductor L1 is an energy storage device; capacitors C3, C4, and C5 are output filter capacitors, which are generally large capacitors connected in parallel with small capacitors. They can simultaneously filter out noise interference in the high-frequency and low-frequency bands to ensure the stability of the output voltage; resistor R9 is a discharge resistor to ensure that the output +5V is not completely unloaded.

[0059] The 5V voltage, after passing through the BUCK chip U2, outputs a negative voltage of -2.5V / -1.65V / -0.55V to power subsequent circuits. U2, D3, L2, SW1, C15, R16, R17, R18, R19, R20, R21, R22, R23, R24, Z1, C11, C12, C13, C14, C15, and C16 form the BUCK circuit, outputting voltages of -2.5V / -1.65V / -0.55V. Chip U2 is a MAX764ESA. Diode D3 is a freewheeling diode, providing a freewheeling path for inductor current during the switching transistor's off-state. Inductor L2 is an energy storage element. Capacitor C15 is the output filter capacitor, ensuring voltage stability. Resistor R23 and capacitor C14 form an RC filter to absorb switching fluctuations. Voltage spikes; SW1, R16, R17, R18, R19, and R24 form the FB voltage divider selection circuit. Resistor R24 ​​is used for downward bias of the FB pin, and switch SW1 selects upward bias, thus making the voltage at the FB pin adjustable. To prevent abnormal output during the neutral period when the toggle switch is activated, resistor R16 is connected in parallel to the upward bias, ensuring the output voltage remains within the acceptable range. Currently, the selectable output voltages are -2.5V / -1.65V / -0.55V. Resistors R20 and R21 form a voltage divider, biasing the voltage across resistor R22 from negative to positive. This voltage is then filtered by the RC filter formed by resistor R22 and capacitor C13 before reaching the main control MCU circuit, allowing the MCU to determine the output voltage. Diode Z1 is a 3.3V TVS diode, used to protect the chip's I / O ports. This circuit achieves a stable 5V output and stable output voltages of -2.5V / -1.65V / -0.55V.

[0060] Please see Figure 3 The MCU power supply circuit takes a 5V input voltage, which is then stabilized at 3.3V after passing through the voltage regulator U3, powering the main control MCU circuit. The voltage regulator U3 is model LD1117AL-33-AA3-AR. Capacitors C17 and C21 are input filter capacitors, capacitors C18, C19, and C20 are output filter capacitors, and resistor R25 is a dummy load to ensure that the output is never floating under any circumstances.

[0061] In this embodiment: Please refer to Figure 4The RS485 communication circuit includes chip IC1, model ST3485EBDR. Pin 1 of chip IC1 is connected to one end of resistor R71 and one end of resistor R66. The other end of resistor R71 is connected to the main control MCU circuit, and the other end of resistor R66 is connected to 3.3V voltage. Pins 2 and 3 of chip IC1 are connected to one end of resistor R74 and one end of resistor R80. The other end of resistor R74 is connected to the main control MCU circuit, and the other end of resistor R80 is grounded. Pin 4 of chip IC1 is connected to one end of resistor R76, and the other end of resistor R76 is connected to the main control MCU circuit. Pin 6 of chip IC1 is connected to the second terminal of interface CN4 through resistors R75 and R81 in sequence. Pin 7 of chip IC1 is connected to the first terminal of interface CN4 through resistors R72 and R67 in sequence.

[0062] Diodes D4 and D6 are ESD protection diodes used to prevent electrostatic damage to the device. The rest are standard peripheral circuitry for the ST3485EBDR; the principle can be found in the datasheet. This circuit enables RS485 communication.

[0063] In this embodiment: Please refer to Figure 5 The infrared signal input circuit includes amplifier U6. The non-inverting input of amplifier U6 is connected to the negative terminal of Zener diode Z10, one end of resistor R78, one end of capacitor C28, and one end of resistor R65. The other end of capacitor C28 is grounded. The positive terminal of Zener diode Z10 is grounded through resistor R82. The other end of resistor R78 is connected to the external IR input signal PWM_IN. The inverting input of amplifier U6 is connected to one end of resistor R64 and one end of resistor R68. The other end of resistor R68 is grounded. The other end of resistor R64 is connected to the other end of resistor R65 and a 5V voltage. The output terminal of amplifier U6 is connected to one end of resistor R69 and one end of resistor R73. The other end of resistor R69 is connected to a 3.3V voltage. The other end of resistor R73 outputs the signal PWM_OUT.

[0064] The external input PWM_IN is compared by amplifier U6, and a 3.3V PWM_OUT signal is output to the main control MCU circuit. This circuit is compatible with PWM inputs from -2.5V to 2.5V. Resistor R65 provides a 5V pull-up bias to the input voltage. When the input is -2.5V, the non-inverting input of the amplifier is 1.25V, ensuring that the input voltage of amplifier U6 is always positive. When the input voltage is higher than 0.5V, the output is high; conversely, the output is low, meeting the minimum input voltage requirement of ±1V. The amplifier U6 is model TS391RILT4. Z10 and R82 are a TVS voltage regulator and a current-limiting resistor, respectively, protecting the input of amplifier U6. Capacitor C28 is the input filter capacitor for amplifier U6. Resistors R64 and R68 form a comparison voltage point of 2.5V through voltage division. Capacitor C24 is the power input filter capacitor for amplifier U6. Resistor R69 is the output high-level pull-up resistor. Resistor R73 is the output current-limiting resistor connected to the main control MCU circuit. This circuit can realize wide-range positive and negative PWM signal recognition.

[0065] In this embodiment: Please refer to Figure 6 The main control MCU circuit includes chip U7, model STM32G474CBT6. Pins 31, 32, and 33 of chip U7 are connected to the RS485 communication circuit, pin 25 of chip U7 is connected to the infrared signal input circuit, and pins 8, 9, 10, 13, 15, 22, and 40 of chip U7 are connected to the output level conversion circuit.

[0066] Capacitors C34 and C35 are filter capacitors for the VCC power supply input; X1 is an external crystal oscillator; resistor R79, capacitor C31, and diode D5 form a reset circuit, with resistor R79 acting as a pull-up resistor for the reset pin, capacitor C31 as a filter capacitor, and diode D5 discharging rapidly when the power is off, causing chip U7 to enter reset mode. The remaining capacitors C41, C42, C45, C46, ​​C47, C48, C49, and C32 are all external input or voltage input filter capacitors; capacitors C33 and C40 are resonant capacitors for the crystal oscillator.

[0067] In this embodiment: Please refer to Figure 7 The output level conversion circuit includes chip U8, model number SN74LVC8T245QPWRQ1. Pins 3 to 9 of chip U8 are connected to the main control MCU circuit, pins 20 and 21 of chip U8 are connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit, and pins 15 to 19 of chip U8 are connected to the board under test.

[0068] Chip U7 outputs 3.3V A, B, Z, U, V, W, R signals, which are then converted to 5V A, B, Z, U, V, W, R signals by chip U8 and sent to the board under test. U8 is a level converter chip, model SN74LVC8T245QPWRQ1. This chip selects the input / output direction via DIR and OE. Since it is designed as an AtoB (A1-A8 pins to B1-B8 pins), the DIR pin is pulled high by default. The OE pin controls whether a signal is output; if high, no output; if low, output, controlled by chip U7. Resistors R95 and R93 ground unused input / output ports. Z3 to Z9 are ESD protection diodes to prevent electrostatic discharge damage. Resistors R84, R86, R87, R88, R89, R90, and R92 are current-limiting resistors to prevent direct current transmission between chip U8 and external components. This circuit can convert a 3.3V high-frequency PWM signal to 5V, and greatly increases the output capability.

[0069] In this embodiment: Please refer to Figure 8 The AB positive and negative voltage output circuit includes two positive and negative voltage output sub-circuits, which process signals A1 and B1 respectively. Each sub-circuit includes amplifier U5, transistor Q6, and transistor Q10. The non-inverting input of amplifier U5 is connected to signal A1 via resistor R59. The inverting input of amplifier U5 is connected to one end of resistor R46 and one end of resistor R52. The other end of resistor R52 is grounded, and the other end of resistor R46 is connected to a 5V voltage. The output of amplifier U5 is connected to one end of resistor R57, one end of resistor R28, and resistor R... One end of resistor R29, one end of resistor R35, one end of resistor R41, and the other end of resistor R28 are connected to a 5V voltage. The other end of resistor R29 is grounded. The other end of resistor R35 is connected to the collector of transistor Q6. The emitter of transistor Q6 is grounded. The base of transistor Q6 is connected to the main control MCU circuit through resistor R36. The other end of resistor R41 is connected to the collector of transistor Q10. The emitter of transistor Q10 is grounded. The base of transistor Q10 is connected to the main control MCU circuit through resistor R47. The other end of resistor R57 is connected to the board under test through interface J1.

[0070] Input signal A1, amplifier U5 ground is connected to a negative voltage (e.g., -2.5V), amplifier U5 output is pulled up to 2.5V, so the waveform output through amplifier U5 is a ±2.5V PWM wave, used for output to the host computer; amplifiers U4 / U5 are TS391RILT; resistors R46 and R52 are used to set the comparison voltage point at 2.5V; capacitor C22 is the filter capacitor for the input of amplifier U5; resistors R57 and R59 are current-limiting resistors used to increase impedance; resistors R36 and R47 are transistor drive resistors; resistor R28 is used for external pull-up, and resistors R29, R35, and R41 are corresponding pull-down resistors. When VO- is detected to be a certain negative voltage (-2.5V / -1.65V / -0.55V), the corresponding transistor is turned on, and the positive and negative voltages are symmetrical through voltage division; the principle of the left and right circuits is the same, and will not be explained again. This circuit realizes the output of positive and negative PWM signals.

[0071] In this embodiment: Please refer to Figure 9 The AB output voltage selection circuit includes two output voltage selection sub-circuits, which process the A1 signal and the B1 signal respectively. Each output voltage selection sub-circuit includes a resistor R31. One end of the resistor R31 is connected to the A1 signal, and the other end of the resistor R31 is connected to one end of the resistor R33 and one end of the resistor R55. The other end of the resistor R33 is connected to the collector of transistor Q11, and the emitter of transistor Q11 is grounded. The base of transistor Q11 is connected to one end of the resistor R39, and the other end of the resistor R39 is connected to the main control MCU circuit. The other end of the resistor R55 is connected to the collector of transistor Q13, and the emitter of transistor Q13 is grounded. The base of transistor Q13 is connected to one end of the resistor R61, and the other end of the resistor R61 is connected to the main control MCU circuit.

[0072] The input 5V signal A1 / B1 is divided into three output voltage signals: 1.1V, 3.3V, and 5V. The direct output is 5V. By controlling whether transistor Q11 or Q13 is turned on, the voltage across the voltage divider (R31) is different, resulting in different voltage values ​​at A1-1, thus completing the output of 1.1V, 3.3V, and 5V voltage signals. R39 is the drive resistor, R44 is the pull-down resistor to ensure that the transistor is driven low by default, transistor Q11 is an NPN transistor BC817, resistor R33 is the lower bias resistor in the voltage divider circuit, and resistor R31 is the upper bias resistor in the voltage divider circuit. The principle of the left and right circuits is the same, so it will not be explained again.

[0073] The working principle of this utility model is as follows: the power supply circuit is used to supply the working voltage; the RS485 communication circuit is used to establish communication between the main control MCU circuit and the host computer; the infrared signal input circuit is used to receive the external IR input signal PWM_IN, and after processing by the comparator, outputs a 3.3V IR output signal PWM_OUT to the main control MCU circuit (the main control MCU circuit performs frequency multiplication on PWM_OUT, outputs an R signal with an amplitude of 3.3V, and then outputs a 5V R signal to the board under test through the output level conversion circuit); the main control MCU circuit is used to generate A, B, Z, U, V, W, and R signals with an amplitude of 3.3V to the output. Level conversion circuit; The output level conversion circuit is used to convert the 3.3V amplitude A, B, Z, U, V, W, R signals into 5V amplitude A1, B1, Z1, U1, V1, W1, R1 signals, and the 5V amplitude Z1, U1, V1, W1, R1 signals are output to the board under test; The 5V amplitude A1 and B1 signals are output to the board under test through the AB positive and negative voltage output circuit or the AB output voltage selection circuit; The AB positive and negative voltage output circuit is used to convert the A1 and B1 signals into positive and negative oscillating PWM waves and output them to the board under test; The AB output voltage selection circuit is used to adjust the amplitude of the 5V amplitude A1 and B1 signals before outputting them to the board under test.

[0074] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects.

[0075] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A novel analog encoder testing system, characterized in that, This new analog encoder testing system includes: Power supply circuit, used to supply the working voltage; The RS485 communication circuit is used to establish communication between the main control MCU circuit and the host computer. The infrared signal input circuit is used to receive the external IR input signal PWM_IN, and after processing by the comparator, outputs a 3.3V IR output signal PWM_OUT to the main control MCU circuit. The main control MCU circuit is used to generate A, B, Z, U, V, W, R signals with an amplitude of 3.3V to the output level conversion circuit; The output level conversion circuit converts the 3.3V A, B, Z, U, V, W, R signals into 5V A1, B1, Z1, U1, V1, W1, R1 signals. The 5V Z1, U1, V1, W1, R1 signals are then output to the board under test. The 5V A1 and B1 signals are output to the board under test via the AB positive and negative voltage output circuit or the AB output voltage selection circuit. The AB positive and negative voltage output circuit is used to convert the A1 and B1 signals into positive and negative PWM waves and output them to the board under test. The AB output voltage selection circuit is used to adjust the amplitude of the 5V A1 and B1 signals before outputting them to the board under test. The power supply circuit is connected to the RS485 communication circuit, the infrared signal input circuit, the main control MCU circuit, the output level conversion circuit, and the AB positive and negative voltage output circuit. The main control MCU circuit is connected to the RS485 communication circuit, the infrared signal input circuit, and the output level conversion circuit. The output level conversion circuit is connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit.

2. The novel analog encoder testing system according to claim 1, characterized in that, The power supply circuit includes: The power supply reverse connection protection filter circuit is used to receive external power input, output filtered VIN voltage, and provide reverse connection protection. A switching power supply sub-circuit is used to obtain 5V and -2.5V / -1.65V / -0.55V voltages based on VIN voltage; The MCU power supply circuit is used to output a 3.3V voltage based on a 5V voltage to power the main control MCU circuit. The output of the reverse polarity protection filter sub-circuit is connected to the input of the switching power supply sub-circuit, and the output of the switching power supply sub-circuit is connected to the input of the MCU power supply circuit.

3. The novel analog encoder testing system according to claim 1, characterized in that, The RS485 communication circuit includes chip IC1, model ST3485EBDR. Pin 1 of chip IC1 is connected to one end of resistor R71 and one end of resistor R66. The other end of resistor R71 is connected to the main control MCU circuit, and the other end of resistor R66 is connected to 3.3V. Pins 2 and 3 of chip IC1 are connected to one end of resistor R74 and one end of resistor R80. The other end of resistor R74 is connected to the main control MCU circuit, and the other end of resistor R80 is grounded. Pin 4 of chip IC1 is connected to one end of resistor R76, and the other end of resistor R76 is connected to the main control MCU circuit. Pin 6 of chip IC1 is connected to the second terminal of interface CN4 through resistors R75 and R81. Pin 7 of chip IC1 is connected to the first terminal of interface CN4 through resistors R72 and R67.

4. The novel analog encoder testing system according to claim 1, characterized in that, The infrared signal input circuit includes amplifier U6. The non-inverting input of amplifier U6 is connected to the negative terminal of Zener diode Z10, one end of resistor R78, one end of capacitor C28, and one end of resistor R65. The other end of capacitor C28 is grounded. The positive terminal of Zener diode Z10 is grounded through resistor R82. The other end of resistor R78 is connected to the external IR input signal PWM_IN. The inverting input of amplifier U6 is connected to one end of resistor R64 and one end of resistor R68. The other end of resistor R68 is grounded. The other end of resistor R64 is connected to the other end of resistor R65 and a 5V voltage. The output of amplifier U6 is connected to one end of resistor R69 and one end of resistor R73. The other end of resistor R69 is connected to a 3.3V voltage. The other end of resistor R73 outputs the signal PWM_OUT.

5. The novel analog encoder testing system according to claim 1, characterized in that, The main control MCU circuit includes chip U7, model STM32G474CBT6. Pins 31, 32, and 33 of chip U7 are connected to the RS485 communication circuit, pin 25 of chip U7 is connected to the infrared signal input circuit, and pins 8, 9, 10, 13, 15, 22, and 40 of chip U7 are connected to the output level conversion circuit.

6. The novel analog encoder testing system according to claim 1 or 5, characterized in that, The output level conversion circuit includes chip U8, model number SN74LVC8T245QPWRQ1. Pins 3 to 9 of chip U8 are connected to the main control MCU circuit, pins 20 and 21 of chip U8 are connected to the AB positive and negative voltage output circuit and the AB output voltage selection circuit, and pins 15 to 19 of chip U8 are connected to the board under test.

7. The novel analog encoder testing system according to claim 6, characterized in that, The AB positive and negative voltage output circuit includes two sub-circuits, one for positive voltage and one for negative voltage. These sub-circuits process signals A1 and B1 respectively. Each sub-circuit includes amplifier U5, transistor Q6, and transistor Q10. The non-inverting input of amplifier U5 is connected to signal A1 via resistor R59. The inverting input of amplifier U5 is connected to one end of resistor R46 and one end of resistor R52. The other end of resistor R52 is grounded, and the other end of resistor R46 is connected to a 5V voltage. The output of amplifier U5 is connected to one end of resistor R57, one end of resistor R28, and resistor R... One end of resistor R29, one end of resistor R35, one end of resistor R41, and the other end of resistor R28 are connected to a 5V voltage. The other end of resistor R29 is grounded. The other end of resistor R35 is connected to the collector of transistor Q6. The emitter of transistor Q6 is grounded. The base of transistor Q6 is connected to the main control MCU circuit through resistor R36. The other end of resistor R41 is connected to the collector of transistor Q10. The emitter of transistor Q10 is grounded. The base of transistor Q10 is connected to the main control MCU circuit through resistor R47. The other end of resistor R57 is connected to the board under test through interface J1.

8. The novel analog encoder testing system according to claim 6, characterized in that, The AB output voltage selection circuit includes two output voltage selection sub-circuits, which process the A1 signal and the B1 signal respectively. Each output voltage selection sub-circuit includes a resistor R31. One end of resistor R31 is connected to the A1 signal, and the other end of resistor R31 is connected to one end of resistor R33 and one end of resistor R55. The other end of resistor R33 is connected to the collector of transistor Q11, and the emitter of transistor Q11 is grounded. The base of transistor Q11 is connected to one end of resistor R39, and the other end of resistor R39 is connected to the main control MCU circuit. The other end of resistor R55 is connected to the collector of transistor Q13, and the emitter of transistor Q13 is grounded. The base of transistor Q13 is connected to one end of resistor R61, and the other end of resistor R61 is connected to the main control MCU circuit.

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