A control panel for welding machine voltage detection

Abstract

The utility model discloses a control panel of welding machine voltage detection is provided in the casing of welding machine, with host computer communication connection, integrated interface circuit, main control circuit, voltage sampling circuit and communication circuit on the control panel, interface circuit connects main control circuit and communication circuit, main control circuit connects voltage sampling circuit, and main control circuit still passes through communication circuit and connects host computer, interface circuit exports power supply to the input external voltage, still exports power supply after reducing voltage to power voltage, voltage sampling circuit samples welding machine voltage, and exports the sampling voltage corresponding to welding machine voltage to main control circuit, main control circuit converts the sampling voltage into digital voltage to host computer through communication circuit and uploads, realize the real -time collection and transmission of welding machine voltage through control panel, and host computer can accurately adjust the output voltage value of welding machine according to the actual detected welding machine voltage, thereby reach the effect of controlling welding machine.

Description

Technical Field

[0001] This utility model relates to the field of numerical control electronic technology, and in particular to a control board for welding machine voltage detection. Background Technology

[0002] During the welding process, the adjustment of the welding machine voltage has a significant impact on the welding effect. Different welding machines have different voltages on the welding cable during operation. It is necessary to adjust the voltage and current reasonably according to the model and specifications of the welding machine and the welding requirements to obtain the best welding results. Since the welding machine voltage directly affects the arc stability, penetration and width, and welding efficiency, it is necessary to monitor the voltage for any abnormalities to avoid problems such as incomplete welds and burn-through, and to prevent the risk of electric shock or fire.

[0003] Currently, welding machine voltage is primarily measured using devices such as digital multimeters or voltmeters. Digital multimeters are suitable for measuring the output voltage of most welding machines, but they need to be manually set to DC voltage (DCV) or AC voltage (ACV) mode depending on the type of welding machine. Connect the red probe to the positive output terminal of the welding machine and the black probe to the negative terminal; start the welding machine and read the voltage value displayed on the multimeter. Voltmeters are suitable for online testing using the welding machine's built-in voltmeter or an external standard voltmeter. Voltmeters require periodic calibration; during testing, observe whether the voltmeter reading is stable and compare it with the process requirement parameters.

[0004] These testing methods require manual operation, cannot monitor the welding machine voltage in real time, and are susceptible to environmental interference from external testing instruments, which can affect the accuracy of the test values. For welding with high precision requirements, they cannot output accurate voltage values ​​in real time, thus failing to achieve high-precision welding results.

[0005] Therefore, existing technologies still need to be improved and enhanced. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a control board for welding machine voltage detection, so as to solve the problem that the existing welding machine voltage detection cannot output voltage values ​​in real time.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A control board for voltage detection in a welding machine, wherein the control board is disposed inside the housing of the welding machine and is communicatively connected to the host machine; the control board integrates an interface circuit, a main control circuit, a voltage sampling circuit, and a communication circuit; The interface circuit connects the main control circuit and the communication circuit. The main control circuit is connected to the voltage sampling circuit. The main control circuit is also connected to an external host through the communication circuit. The interface circuit outputs the input external voltage as power and also steps it down to the power supply voltage before outputting it as power. The voltage sampling circuit samples the welding machine voltage and outputs the sampled voltage corresponding to the welding machine voltage to the main control circuit. The main control circuit converts the sampled voltage into a digital voltage and uploads it to the host computer through the communication circuit.

[0008] In the control board for welding machine voltage detection, the interface circuit includes an input interface and a power chip. The fourth pin of the input interface is connected to the input pin of the power chip and the communication circuit. The third pin of the input interface is grounded, and the first pin of the input interface is connected to earth. The output pin of the power chip is the power supply pin, and the ground pin of the power chip is grounded.

[0009] In the control board for welding machine voltage detection, the interface circuit further includes a first capacitor, a second capacitor, and a third capacitor; the first capacitor is connected between pin 4 and pin 3 of the input interface, the second capacitor is connected between the input pin of the power chip and ground, and the third capacitor is connected between the output pin of the power chip and ground.

[0010] In the control board for welding machine voltage detection, the main control circuit includes a controller, a crystal oscillator, a first resistor, a fourth capacitor, a fifth capacitor, and a sixth capacitor. The controller's PA2 pin is connected to the voltage sampling circuit; the controller's OSC_IN / PD0 pin is connected to pin 1 of the crystal oscillator and one end of the fourth capacitor; the controller's OSC_OUT / PD1 pin is connected to pin 2 of the crystal oscillator and one end of the fifth capacitor; pin 3 of the crystal oscillator is connected to the other end of the fourth capacitor, the other end of the fifth capacitor, and ground; the controller's BOOT0 pin is connected to one end of the first resistor; the controller's NRST pin is connected to one end of the sixth capacitor; the other end of the first resistor is connected to the other end of the sixth capacitor and ground; the controller's PB10, PB11, PB12, and PB13 pins are all connected to the communication circuit; the controller's VBAT and VDD pins are both connected to the power supply pins; and the controller's VSS pin and PB2 / BOOT1 pin are both grounded.

[0011] In the control board for welding machine voltage detection, the main control circuit also includes a second resistor and an indicator light. The PA7 pin of the controller is connected to the positive terminal of the indicator light through the second resistor, and the negative terminal of the indicator light is grounded.

[0012] In the control board for welding machine voltage detection, the voltage sampling circuit includes a voltage interface, a third resistor, a fourth resistor, and a fifth resistor; The ground pin of the voltage interface is grounded and connected to the negative terminal of the welding machine's energy storage capacitor. The voltage pin of the voltage interface is connected to one end of the third resistor and connected to the positive terminal of the welding machine's energy storage capacitor. The other end of the third resistor is connected to one end of the fifth resistor and the PA2 pin of the controller through the fourth resistor. The other end of the fifth resistor is grounded.

[0013] In the control board for welding machine voltage detection, the main control circuit also includes a debugging interface. The power supply pin of the debugging interface is connected to the output pin of the power chip, the debugging data pin of the debugging interface is connected to the PA13 / JTMS / SWDIO pin of the controller U2, the debugging clock pin of the debugging interface is connected to the PA14 / JTCK / SWCLK pin of the controller U2, and the ground pin of the debugging interface J1 is grounded.

[0014] In the control board for welding machine voltage detection, the communication circuit includes a communication chip, a sixth resistor, a seventh resistor, an eighth resistor, and a communication interface. The VCC pin of the communication chip is connected to pin 4 of the input interface, and the GNDA pin of the communication chip is grounded; the RO pin of the communication chip... Pins DE, DI, and PB11, PB13, PB12, and PB10 of the controller are connected one-to-one; the SEL pin of the communication chip is connected to the VISO pin of the communication chip; pin A of the communication chip is connected to one end of the sixth resistor and one end of the eighth resistor; pin B of the communication chip is connected to the other end of the sixth resistor and one end of the seventh resistor; the other end of the eighth resistor is connected to pin 2 of the communication interface; the other end of the seventh resistor is connected to pin 3 of the communication interface; and pin GNDB of the communication chip and pin 1 of the communication interface are both connected to digital ground.

[0015] In the control board for welding machine voltage detection, the communication circuit further includes a ninth resistor, a tenth resistor, a seventh capacitor, and an eighth capacitor; One end of the ninth resistor is connected to the GNDB pin of the communication chip and digital ground; the other end of the ninth resistor is connected to one end of the seventh resistor and one end of the eighth resistor; one end of the tenth resistor is connected to one end of the sixth resistor and one end of the eighth resistor; the other end of the tenth resistor is connected to one end of the seventh capacitor, one end of the eighth capacitor and the VISO pin of the communication chip; the other end of the seventh capacitor is connected to the other end of the eighth capacitor and digital ground.

[0016] Compared to existing technologies, the control board for welding machine voltage detection provided by this utility model is housed within the welding machine's casing and communicates with the host computer. The control board integrates an interface circuit, a main control circuit, a voltage sampling circuit, and a communication circuit. The interface circuit connects the main control circuit and the communication circuit, the main control circuit connects to the voltage sampling circuit, and the main control circuit is also connected to the host computer via the communication circuit. The interface circuit outputs power from the input external voltage and also steps it down to the power supply voltage before outputting power. The voltage sampling circuit samples the welding machine voltage and outputs the sampled voltage corresponding to the welding machine voltage to the main control circuit. The main control circuit converts the sampled voltage into a digital voltage and uploads it to the host computer via the communication circuit. By using the control board to achieve real-time acquisition and transmission of the welding machine voltage, the host computer can accurately adjust the output voltage value of the welding machine based on the actual detected welding machine voltage, thereby achieving the effect of controlling the welding machine. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of the control board for welding machine voltage detection provided by this utility model.

[0018] Figure 2 This is a circuit diagram of the interface circuit provided by this utility model.

[0019] Figure 3 This is a circuit diagram of the main control circuit provided by this utility model.

[0020] Figure 4 This is a circuit diagram of the voltage sampling circuit provided by this utility model.

[0021] Figure 5 This is a circuit diagram of the communication circuit provided by this utility model. Detailed Implementation

[0022] This utility model provides a control board for welding machine voltage detection. To make the objectives, technical solutions, and advantages of this utility model clearer and more explicit, the following detailed description, with reference to the accompanying drawings and embodiments, further illustrates the utility model. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this utility model.

[0023] Please also refer to Figures 1 to 4 This utility model provides a control board for welding machine voltage detection, which is installed inside the welding machine housing and communicates with the host computer. The control board integrates an interface circuit 10, a main control circuit 20, a voltage sampling circuit 30, and a communication circuit 40. The interface circuit 10 connects the main control circuit 20 and the communication circuit 40, the main control circuit 20 connects to the voltage sampling circuit 30, and the main control circuit 20 is also connected to the host computer via the communication circuit 40. The interface circuit 10 outputs a +5V input external voltage as power and then steps it down to the power supply voltage before outputting it as power. The voltage sampling circuit 30 samples the welding machine voltage and outputs the sampled voltage corresponding to the welding machine voltage to the main control circuit 20. The main control circuit 20 converts the sampled voltage into a digital voltage and uploads it to the host computer for processing via the communication circuit 40. By using the control board to achieve real-time acquisition and transmission of the welding machine voltage, the host computer can accurately adjust the output voltage value of the welding machine based on the actual detected welding machine voltage, thereby achieving the effect of controlling the welding machine.

[0024] like Figure 2As shown, the interface circuit 10 includes an input interface P1 and a power chip U1. The fourth pin of the input interface P1 is connected to the input pin (IN pin, also known as PIN 3) of the power chip U1 and the communication circuit 40. The third pin of the input interface P1 is grounded to GND (analog ground or circuit ground). The first pin of the input interface P1 is connected to earth ground PE (such as the housing of a welding machine). The output pins (OUT pin, also known as PIN 2 and PIN 4) of the power chip U1 are power supply pins. The ground pin (GND pin, also known as PIN 1) of the power chip U1 is grounded to GND.

[0025] The input interface P1 is a common interface terminal, and its pins can be customized. The power supply chip U1 is preferably an AMS1117-3.3V low-dropout linear regulator with a fixed output voltage of 3.3V. The external input voltage +5V0 is transmitted to the power supply chip U1 through the input interface P1 for conversion processing. The power supply chip U1 outputs a +3.3V power supply voltage to the various downstream circuits, thereby powering up and starting the entire control board.

[0026] Preferably, the interface circuit 10 further includes a first capacitor C1, a second capacitor C2, and a third capacitor C3; the first capacitor C1 is connected between pin 4 and pin 3 of the input interface P1, the second capacitor C2 is connected between the input pin of the power chip U1 and ground GND, and the third capacitor C3 is connected between the output pin of the power chip U1 and ground GND. The first capacitor C1 (preferably 47uF / 16V) is used to filter the external voltage +5V0 output from pin 4 of the input interface P1, the second capacitor C2 (preferably 0.1uF / 16V) is used to filter the external voltage +5V0 at the input pin of the power chip U1, and the third capacitor C3 (preferably 0.1uF / 16V) is used to filter the power supply voltage +3.3V at the output pin of the power chip U1. In a specific implementation, three capacitors can also be set, connected in parallel with C1, C2, and C3 respectively. The two capacitors connected in parallel have the same specifications.

[0027] The main control circuit 20 includes a controller U2, a crystal oscillator Y1, a first resistor R1, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6. The PA2 pin of the controller U2 is connected to the voltage sampling circuit 30. The OSC_IN / PD0 pin of the controller U2 is connected to pin 1 of the crystal oscillator Y1 and one end of the fourth capacitor C4. The OSC_OUT / PD1 pin of the controller U2 is connected to pin 2 of the crystal oscillator Y1 and one end of the fifth capacitor C5. Pin 3 of the crystal oscillator Y1 is connected to the other end of the fourth capacitor C4, the other end of the fifth capacitor C5, and ground GND. The BOOT0 pin is connected to one end of the first resistor R1. The NRST pin of the controller U2 is connected to one end of the sixth capacitor C6. The other end of the first resistor R1 is connected to the other end of the sixth capacitor C6 and ground GND. The PB10, PB11, PB12 and PB13 pins of the controller U2 are all connected to the communication circuit 40. The VBAT and VDD pins (including VDD_1~3 and VDDA pins) of the controller U2 are all connected to the power supply pins. The VSS pins (including VSS_1~3 and VSSA pins) and the PB2 / BOOT1 pin of the controller U2 are all grounded.

[0028] The controller U2 is preferably a 32-bit STM32F103C8T6 microprocessor, used to convert the sampled voltage TEXT_VOLT corresponding to the welding machine voltage collected by the voltage sampling circuit 30 into a digital voltage, which is then transmitted to the communication circuit 40 via UART signals (UART3_TX, UART3_RX, UART3_RTS, and UART3_nRE) to be uploaded to the host. Crystal oscillator Y1, fourth capacitor C4, and fifth capacitor C5 provide the clock signals required for the controller U2 to operate. The BOOT0 pin is grounded through the first resistor R1, and the PB2 / BOOT1 pins are directly grounded, indicating that the controller U2 boots from the internal main Flash and executes the user program. The NRST pin is grounded through the sixth capacitor C6 for power-on reset.

[0029] Preferably, to facilitate understanding the operating status of the controller U2, the main control circuit 20 further includes a second resistor R2 and an indicator light DS. The PA7 pin of the controller U2 is connected to the positive terminal of the indicator light DS through the second resistor R2, and the negative terminal of the indicator light DS is grounded. The controller U2 controls the voltage waveform on the PA7 pin to make the indicator light DS stay on or flash at a set frequency to indicate different operating states, such as power-on, running, debugging, or abnormal.

[0030] Preferably, in order to enable later editing or debugging of the program inside the controller U2, the main control circuit 20 further includes a debugging interface J1. The power supply pin (pin 1) of the debugging interface J1 is connected to the output pin of the power chip U1, and the debugging data pin (pin 2) of the debugging interface J1 is connected to PA13 / JTMS / The SWDIO pin, the debug clock pin (pin 3) of debug interface J1, is connected to PA14 / JTCK of controller U2. The SWCLK pin is the ground pin (pin 4) of the debug interface J1. It connects and communicates with an external debugger via the debug interface J1, transmitting debug commands and program data through the SWDIO signal (bidirectional data line, serial line debug input / output), and using the SWCLK signal (clock line) to transmit timing information to ensure communication synchronization; enabling debugging and online programming of the internal program of the controller U2.

[0031] For example, to ensure stable power supply to controller U2, several 0.1uF / 16V capacitors can be connected in parallel between the VDD pin of controller U2 and ground to increase the filtering effect.

[0032] The voltage sampling circuit 30 includes a voltage interface P2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The ground pin (pin 1) of the voltage interface P2 is grounded and connected to the negative terminal of the welding machine's energy storage capacitor. The voltage pin (pin 2) of the voltage interface P2 is connected to one end of the third resistor R3 and connected to the positive terminal of the welding machine's energy storage capacitor. The other end of the third resistor R3 is connected to one end of the fifth resistor R5 and the PA2 pin of the controller U2 through the fourth resistor R4. The other end of the fifth resistor R5 is grounded.

[0033] The resistance values ​​of the third resistor R3, the fourth resistor R4, and the fifth resistor R5 are 43KΩ, 47KΩ, and 1.2KΩ, respectively. Connecting the voltage interface P2 to the two ends of the welding machine's storage capacitor, and combining the voltage division of these three resistors, the welding machine voltage (input voltage range 5V~200V) can be sampled, and the simulated welding machine voltage sampling voltage TEXT_VOLT is output to the controller U2.

[0034] Preferably, the voltage sampling circuit 30 further includes a ferrite bead FB1 and a diode D1. One end of the ferrite bead FB1 is connected to one end of the fifth resistor R5 and the negative terminal of the diode D1, and the other end of the ferrite bead FB1 is connected to pin PA2 of the controller U2. The positive terminal of the diode D1 is connected to the other end of the fifth resistor R5 and ground. The ferrite bead FB1 is used to burn out when the welding machine voltage is abnormally high to protect the controller U2, and the diode D1 is used for voltage stabilization.

[0035] The communication circuit 40 includes a communication chip U3, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a communication interface P2; the VCC pin of the communication chip U3 is connected to pin 4 of the input interface P1, and the GNDA pins (pins 2 and 8) of the communication chip U3 are grounded to GND; the RO pin of the communication chip U3, Pins 1, 2, 3, and 4 are connected one-to-one with pins PB11, PB13, PB12, and PB10 of controller U2. Pin SEL of communication chip U3 is connected to pin VISO of communication chip U3. Pin A of communication chip U3 is connected to one end of the sixth resistor R6 and one end of the eighth resistor R8. Pin B of communication chip U3 is connected to the other end of the sixth resistor R6 and one end of the seventh resistor R7. The other end of the eighth resistor R8 is connected to pin 2 of communication interface P2. The other end of the seventh resistor R7 is connected to pin 3 of communication interface P2. Pins 9 and 15 of communication chip U3 and pin 1 of communication interface P2 are both connected to digital ground GNDB.

[0036] The communication chip U3 is preferably a CA-IS2092W integrated isolated DC-DC converter with an isolated half-duplex RS-485 transceiver chip. Communication interface P2 transmits RS485 signals; R6, R7, and R8 are used for signal matching on the RS485 communication line. Communication chip U3 converts UART signals (UART3_TX, UART3_RX, UART3_RTS, and UART3_nRE signals) loaded with digital voltage into RS485 signals (485±), which are then uploaded to the external host via communication interface P2, thus enabling communication between the control board and the host. The host can obtain the current welding voltage based on the received RS485 signal, allowing users to precisely adjust the welding machine's output voltage, thereby controlling the welding machine and improving welding results. RS485 signal communication offers stronger anti-interference capabilities, and the communication chip U3 has built-in isolation functionality to prevent the welding machine's high voltage from affecting the control board.

[0037] Preferably, the communication circuit 40 further includes a ninth resistor R9, a tenth resistor R10, a seventh capacitor C7, and an eighth capacitor C8; one end of the ninth resistor R9 is connected to the GNDB pin (PIN 9) of the communication chip U3 and the digital ground GNDB, and the other end of the ninth resistor R9 is connected to one end of the seventh resistor R7 and one end of the eighth resistor R8; one end of the tenth resistor R10 is connected to one end of the sixth resistor R6 and one end of the eighth resistor R8; the other end of the tenth resistor R10 is connected to one end of the seventh capacitor C7, one end of the eighth capacitor C8, and the VISO pin of the communication chip U3; the other end of the seventh capacitor C7 is connected to the other end of the eighth capacitor C8 and the digital ground GNDB.

[0038] R9 is used to pull the 485- signal low when there is no signal transmission. R10 is used to pull the 485+ signal to the VISO level (isolation power supply) when there is no signal transmission. C7 and C8 are used to filter the VISO voltage on the VISO pin.

[0039] Preferably, the communication circuit 40 further includes an eleventh resistor R11, which is connected to the communication chip U3. Between the feet and the ground; R11 is used for setting. The voltage on the foot is initially low.

[0040] In summary, the control board for welding machine voltage detection of this utility model detects the welding machine voltage in real time during operation, performs analog-to-digital conversion, and promptly uploads the data to the host computer. The host computer can then precisely adjust the output voltage value of the welding machine based on the actual detected voltage, forming a closed loop of automatic welding machine voltage monitoring without manual operation. This achieves the goal of controlling the welding machine and improving welding performance. No external testing instruments are required, saving costs. The circuit detection results are accurate and displayed promptly, meeting higher precision welding requirements.

[0041] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A control board for welding machine voltage detection, characterized in that, The control board is housed inside the welding machine's casing and is connected to the main unit for communication. The control board integrates interface circuitry, main control circuitry, voltage sampling circuitry, and communication circuitry. The interface circuit connects the main control circuit and the communication circuit. The main control circuit is connected to the voltage sampling circuit. The main control circuit is also connected to an external host through the communication circuit. The interface circuit outputs the input external voltage as power and also steps it down to the power supply voltage before outputting it as power. The voltage sampling circuit samples the welding machine voltage and outputs the sampled voltage corresponding to the welding machine voltage to the main control circuit. The main control circuit converts the sampled voltage into a digital voltage and uploads it to the host computer through the communication circuit.

2. The control board for welding machine voltage detection according to claim 1, characterized in that, The interface circuit includes an input interface and a power chip. Pin 4 of the input interface is connected to the input pin of the power chip and the communication circuit. Pin 3 of the input interface is grounded, and pin 1 of the input interface is grounded. The output pin of the power chip is the power supply pin, and the ground pin of the power chip is grounded.

3. The control board for welding machine voltage detection according to claim 2, characterized in that, The interface circuit also includes a first capacitor, a second capacitor, and a third capacitor; the first capacitor is connected between pin 4 and pin 3 of the input interface, the second capacitor is connected between the input pin of the power chip and ground, and the third capacitor is connected between the output pin of the power chip and ground.

4. The control board for welding machine voltage detection according to claim 2, characterized in that, The main control circuit includes a controller, a crystal oscillator, a first resistor, a fourth capacitor, a fifth capacitor, and a sixth capacitor; The controller's PA2 pin is connected to the voltage sampling circuit; the controller's OSC_IN / PD0 pin is connected to pin 1 of the crystal oscillator and one end of the fourth capacitor; the controller's OSC_OUT / PD1 pin is connected to pin 2 of the crystal oscillator and one end of the fifth capacitor; pin 3 of the crystal oscillator is connected to the other end of the fourth capacitor, the other end of the fifth capacitor, and ground; the controller's BOOT0 pin is connected to one end of the first resistor; the controller's NRST pin is connected to one end of the sixth capacitor; the other end of the first resistor is connected to the other end of the sixth capacitor and ground; the controller's PB10, PB11, PB12, and PB13 pins are all connected to the communication circuit. The controller's VBAT and VDD pins are both connected to the power supply pins, while the controller's VSS and PB2 / BOOT1 pins are both grounded.

5. The control board for welding machine voltage detection according to claim 4, characterized in that, The main control circuit also includes a second resistor and an indicator light. The PA7 pin of the controller is connected to the positive terminal of the indicator light through the second resistor, and the negative terminal of the indicator light is grounded.

6. The control board for welding machine voltage detection according to claim 4, characterized in that, The voltage sampling circuit includes a voltage interface, a third resistor, a fourth resistor, and a fifth resistor; The ground pin of the voltage interface is grounded and connected to the negative terminal of the welding machine's energy storage capacitor. The voltage pin of the voltage interface is connected to one end of the third resistor and connected to the positive terminal of the welding machine's energy storage capacitor. The other end of the third resistor is connected to one end of the fifth resistor and the PA2 pin of the controller through the fourth resistor. The other end of the fifth resistor is grounded.

7. The control board for welding machine voltage detection according to claim 4, characterized in that, The main control circuit also includes a debugging interface. The power supply pin of the debugging interface is connected to the output pin of the power chip. The debugging data pin of the debugging interface is connected to the PA13 / JTMS / SWDIO pin of the controller U2. The debugging clock pin of the debugging interface is connected to the PA14 / JTCK / SWCLK pin of the controller U2. The ground pin of the debugging interface J1 is grounded.

8. The control board for welding machine voltage detection according to claim 4, characterized in that, The communication circuit includes a communication chip, a sixth resistor, a seventh resistor, an eighth resistor, and a communication interface; The VCC pin of the communication chip is connected to pin 4 of the input interface, and the GNDA pin of the communication chip is grounded; the RO pin of the communication chip... Pins DE, DI and PB11, PB13, PB12 and PB10 of the controller are connected one-to-one; The SEL pin of the communication chip is connected to the VISO pin of the communication chip. The A pin of the communication chip is connected to one end of the sixth resistor and one end of the eighth resistor. The B pin of the communication chip is connected to the other end of the sixth resistor and one end of the seventh resistor. The other end of the eighth resistor is connected to pin 2 of the communication interface. The other end of the seventh resistor is connected to pin 3 of the communication interface. The GNDB pin of the communication chip and pin 1 of the communication interface are both connected to digital ground.

9. The control board for welding machine voltage detection according to claim 8, characterized in that, The communication circuit also includes a ninth resistor, a tenth resistor, a seventh capacitor, and an eighth capacitor; One end of the ninth resistor is connected to the GNDB pin of the communication chip and digital ground; the other end of the ninth resistor is connected to one end of the seventh resistor and one end of the eighth resistor; one end of the tenth resistor is connected to one end of the sixth resistor and one end of the eighth resistor; the other end of the tenth resistor is connected to one end of the seventh capacitor, one end of the eighth capacitor and the VISO pin of the communication chip; the other end of the seventh capacitor is connected to the other end of the eighth capacitor and digital ground.

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