Control circuit and system for cooling water tank of argon welding machine

Abstract

The application relates to a control circuit and system of a cooling water tank for an argon welding machine, which circuit comprises an interface circuit for being connected with a display control panel and communicating with the display control panel; a temperature detection circuit connected with the interface circuit, used for reacting to temperature changes of the cooling water tank and transmitting a temperature signal to the interface circuit based on the temperature changes of the cooling water tank; a switch detection circuit connected with the interface circuit, used for transmitting a switch closing signal to the interface circuit when the cooling water tank is connected with a welding gun; and a power supply circuit for providing working voltage for the temperature detection circuit and the switch detection circuit. After the temperature of the cooling water tank changes, the temperature detection circuit transmits the temperature signal to an upper computer; after the welding gun is connected with the cooling water tank, the switch detection circuit transmits the switch closing signal to the upper computer, so that workers can know the condition of the cooling water tank in time without personally detecting. The application has the effect of helping to improve the use convenience of the cooling water tank.

Description

Technical Field

[0001] This invention relates to the field of welding machine cooling water tanks, and in particular to a control circuit and system for a cooling water tank for an argon welding machine. Background Technology

[0002] Argon welding machines, also known as argon arc welding machines, are machines that use an argon arc welding process, employing a high-pressure breakdown arc initiation method. During operation, a welding torch holds industrial tungsten or activated tungsten as a non-consumable electrode to weld the workpiece. Before welding, a cooling water tank needs to be connected to the welding torch to cool it and lower its operating temperature.

[0003] The argon welding machine cooling water tank in related technologies includes a tank for holding cooling water, a water pump for supplying cooling water, a cooling water output port for connecting to the welding torch, a cooling water return port for connecting to the welding torch, and a radiator for dissipating heat from the tank. After connecting both the cooling water output port and the cooling water return port to the welding torch, the water pump can be started. The water pump delivers cooling water from the tank to the cooling water output port. The cooling water flows through the welding torch and returns to the tank through the cooling water return port, thus cooling the welding torch. When the radiator is powered on, it cools the cooling water tank, facilitating the reduction of the temperature of the cooling water and the water pump, ensuring the safe operation of the cooling water tank, and extending its service life.

[0004] Regarding the aforementioned technologies, the inventors believe that whether the cooling water tank is connected to the welding torch or whether the temperature of the cooling water tank is too high, workers need to manually inspect and make judgments, which affects the ease of use of the cooling water tank. Summary of the Invention

[0005] To improve the ease of use of cooling water tanks for argon welding machines, this invention provides a control circuit and system for a cooling water tank for argon welding machines.

[0006] Firstly, the control circuit for a cooling water tank of an argon welding machine provided in this application adopts the following technical solution: An interface circuit is used to connect to and communicate with the display and control panel. A temperature detection circuit, connected to the interface circuit, is used to reflect the temperature change of the cooling water tank and transmit a temperature signal to the interface circuit based on the temperature change of the cooling water tank. A switch detection circuit, connected to the interface circuit, is used to transmit a switch closure signal to the interface circuit when the cooling water tank is connected to the welding torch; and, A power supply circuit is used to provide operating voltage for the temperature detection circuit and the switch detection circuit.

[0007] By adopting the above technical solution, the interface circuit is connected to the display and control panel. The temperature detection circuit transmits the temperature signal to the interface circuit, and the switch detection circuit transmits the switch closure signal to the interface circuit. Both the temperature signal and the switch closure signal are transmitted to the display and control panel through the interface circuit. Workers can easily and quickly know the temperature change of the cooling water tank and whether the cooling water tank is connected to the welding torch through the display and control panel.

[0008] Optionally, the temperature detection circuit includes a temperature detection voltage input terminal VINa, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a third diode D3, and a thermistor R0. One end of the first capacitor C1 is connected to the temperature detection voltage input terminal VINa, and the other end is grounded; one end of the first resistor R1 is connected to the temperature detection voltage input terminal VINa, and the other end of the first resistor R1 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is grounded; the end of the second capacitor C2 connected to the first resistor R1 is connected to a first pin N1, and the grounded end of the second capacitor C2 is connected to a second pin N2; one end of the thermistor R0 is connected to the first pin N1, and the other end is connected to the second pin N2; the third capacitor C3 is connected in parallel with the second capacitor C2; one end of the second resistor R2 is connected to the second capacitor C2... 2. One end of the first diode D1 is connected to the first resistor R1, and the other end is connected to the interface circuit; the cathode of the first diode D1 is connected to the temperature detection voltage input terminal VINa, and the anode is connected to the end of the second resistor R2 and the second capacitor C2; the cathode of the second diode D2 is connected to the end of the second resistor R2 and the second capacitor C2, and the anode is grounded; the cathode of the third diode D3 is connected to the end of the second resistor R2 and the interface circuit, and the anode is connected to the end of the second capacitor C2 that is grounded; one end of the fourth capacitor C4 is connected to the end of the second resistor R2 and the interface circuit, and the other end is connected to the end of the second capacitor C2 that is grounded.

[0009] By adopting the above technical solution, the resistance of the thermistor changes with the temperature of the cooling water tank, thereby causing a change in the temperature signal output by the temperature detection circuit. This allows workers to easily monitor the temperature changes of the cooling water tank via the display panel. Furthermore, the thermistor's high sensitivity helps improve the accuracy of the temperature changes detected by the workers through the display panel. In addition, the thermistor is easily replaced via its first and second pins in the temperature detection circuit, facilitating the maintenance of the cooling water tank and further enhancing its usability.

[0010] Optionally, the temperature detection circuit further includes a first common-mode inductor L1 and a second common-mode inductor L2; One end of the first coil of the first common-mode inductor L1 is connected to the first pin N1, and the other end is connected to the end of the second capacitor C2 and the first resistor R1; one end of the second coil of the first common-mode inductor L1 is connected to the second pin N2, and the other end is connected to the end of the second capacitor C2 that is grounded; The first coil of the second common-mode inductor L2 is connected in series between the second resistor R2 and the interface circuit; one end of the second coil of the second common-mode inductor L2 is grounded, and the other end is connected to the ground terminal of the interface circuit.

[0011] By adopting the above technical solution, the two common-mode inductors help to filter out high-frequency signals and resist interference signals, thereby helping to improve the stability of the temperature signal transmitted by the temperature detection circuit.

[0012] Optionally, the switch detection circuit includes a third pin N3, a fourth pin N4, a fifth capacitor C5, a sixth capacitor C6, a fourth diode D4, a fifth diode D5, a third resistor R3, a fourth resistor R4, a first optocoupler U1, a first voltage input terminal VINb for switch detection, and a second voltage input terminal VINc for switch detection. The third pin N3 and the fourth pin N4 are used to connect to the water tank switch. When the water tank switch is closed, the third pin N3 and the fourth pin N4 are connected; when the water tank switch is open, the third pin N3 and the fourth pin N4 are disconnected. The third pin N3 is grounded, and the fourth pin N4 is connected to the cathodes of both the fourth diode D4 and the fifth diode D5. The two ends of the fifth capacitor C5 are connected to the ground terminal of the third pin N3 and the fourth pin N4, respectively. The anode of the fourth diode D4 is grounded. The anode of the fifth diode D5 is connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the first output terminal of the first optocoupler U1. The first voltage input terminal VINb for switch detection is connected to the first input terminal of the first optocoupler U1. The second output terminal of the first optocoupler U1 is grounded, and the third output terminal of the first optocoupler U1 is connected to the interface circuit for transmitting a switch closure signal to the interface circuit. The two ends of the sixth capacitor C6 are respectively connected to the second output terminal and the third output terminal of the first optocoupler U1; the second voltage input terminal VINc of the switch detection is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the third output terminal of the first optocoupler U1.

[0013] By adopting the above technical solution, after the welding torch is connected to the cooling water tank, the third and fourth pins are connected. At this time, voltage flows through the first input and first output terminals of the first optocoupler U1, causing a low level to be generated at the third output terminal of the first optocoupler U1. The low level, after passing through the pull-up resistor R4, forms a switch closing signal, which is transmitted to the interface circuit. This allows workers to know that the cooling water tank and welding torch are successfully connected via the display panel, without the need for workers to manually check whether the cooling water tank and welding torch are connected or whether the connection is sufficient, thus improving the ease of use of the cooling water tank. In addition, using an optocoupler helps to reduce interference in the circuit.

[0014] Optionally, the interface circuit is also connected to a water tank power supply control circuit for controlling the power-on and power-off of the water tank.

[0015] By adopting the above technical solution, the interface circuit is connected to the water tank power supply control circuit, enabling control of the water tank's power-on and power-off states. This allows workers to transmit control signals to the interface circuit via the display panel, thereby controlling the cooling water tank's power-on or power-off, which helps improve the ease of use of the cooling water tank.

[0016] Optionally, the water tank power supply control circuit includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a transistor Q1, a MOSFET Q2, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a sixth diode D6, a second optocoupler U2, a first power supply control voltage input terminal VINd, a second power supply control voltage input terminal VINe, a third power supply control voltage input terminal VINf, and a fourth power supply control voltage input terminal VINg. One end of the fifth resistor R5 is connected to the interface circuit, and the other end is connected to one end of the sixth resistor R6 and the base of the transistor Q1; the other end of the sixth resistor R6 and the emitter of the transistor Q1 are both grounded; the collector of the transistor Q1 is connected to the first output terminal of the second optocoupler U2; the first input terminal of the second optocoupler U2 is connected to one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the first voltage input terminal VINd of the power supply control. The second voltage input terminal VINe of the power supply control is connected to the second input terminal of the second optocoupler U2. One end of the seventh capacitor C7 is connected to the second voltage input terminal VINe of the power supply control, and the other end is grounded. The second output terminal of the second optocoupler U2 is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the eighth capacitor C8, one end of the ninth resistor R9, and the gate of the MOS transistor Q2. The other end of the eighth capacitor C8, the other end of the ninth resistor R9, and the source of the MOS transistor Q2 are all grounded. The third voltage input terminal VINf of the power supply control is connected to the input terminal of the water tank relay coil. The drain of the MOS transistor Q2 is connected to the output terminal of the water tank relay coil. The anode of the sixth diode D6 is connected to the output terminal of the water tank relay coil, and the cathode is connected to the input terminal of the water tank relay coil. The fourth voltage input terminal VINg of the power supply control is connected to the moving contact terminal of the water tank relay, and the stationary contact terminal of the water tank relay is connected to the power supply pin; one end of the tenth resistor R10 is connected to the moving contact terminal of the water tank relay, and the other end is connected to one end of the ninth capacitor C9; the other end of the ninth capacitor C9 is connected to the moving contact terminal of the water tank relay.

[0017] By adopting the above technical solution, the second optocoupler helps to isolate the interference between the input signal and the output signal, which facilitates the improvement of the control stability of the power supply to the cooling water tank.

[0018] Optionally, the power supply circuit includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth resistor R15, a twelfth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, a twelfth capacitor C16, a twelfth capacitor C17, a twelfth capacitor C18, a thirteenth capacitor C19, a twelfth capacitor C10, a twelfth capacitor C11, a thirteenth capacitor C11, a thirteenth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, a twel Capacitor C15, sixteenth capacitor C16, seventeenth capacitor C17, eighteenth capacitor C18, nineteenth capacitor C19, twentieth capacitor C20, twenty-first capacitor C21, twenty-second capacitor C22, twenty-third capacitor C23, twenty-fourth capacitor C24, seventh diode D7, eighth diode D8, ninth diode D9, tenth diode D10, primary coil, first stage coil, second stage coil, third stage coil, power control chip U0, third optocoupler U3, three-terminal regulator U4, rectifier chip U5, first voltage output port OUT1, second voltage output port OUT2 and third voltage output port OUT3; The primary coil, the first secondary coil, the second secondary coil, and the third secondary coil are all wound on a magnetic core. The primary coil is wound on one side of the magnetic core, and the first secondary coil, the second secondary coil, and the third secondary coil are wound on the other side of the magnetic core, in order to form a transformer. One end of the eleventh resistor R11 is connected to the power input terminal of the power supply circuit, and the other end is connected to the corresponding terminal of the primary coil; one end of the eleventh capacitor C11, one end of the twelfth resistor R12, one end of the seventeenth resistor R17, and one end of the eighteenth resistor R18 are all connected to the corresponding terminal of the primary coil; the other end of the eleventh capacitor C11 is connected to the signal ground terminal; the other end of the twelfth resistor R12 is connected in series with the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor R16. 6. One end of the sixteenth resistor R16 is connected to the voltage input pin of the power control chip U0; the other ends of the twelfth capacitor C12, the seventeenth resistor R17, and the eighteenth resistor R18 are all connected to one end of the nineteenth resistor R19; the other end of the nineteenth resistor R19 is connected to the cathode of the seventh diode D7; the anode of the seventh diode D7 is connected to both the opposite-name terminal of the primary coil and the signal input pin of the power control chip U0; the signal output pin and ground pin of the power control chip U0 are both connected to the signal ground terminal. One end of the thirteenth capacitor C13 is connected to the same-name terminal of the primary coil, and the other end is connected to the opposite-name terminal of the first primary coil; the same-name terminal of the first primary coil is connected to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is connected to the first voltage output port OUT1; the anode and cathode of the eighth diode D8 are connected in parallel with a twentieth resistor R20 and a fourteenth capacitor C14 arranged in series. One end of the fifteenth capacitor C15 is connected to the cathode of the eighth diode D8, and the other end is connected to the opposite-named terminal of the first stage coil; one end of the twenty-first resistor R21, one end of the sixteenth capacitor C16, and one end of the seventeenth capacitor C17 are all connected to the cathode of the eighth diode D8; the other ends of the twenty-first resistor R21, the sixteenth capacitor C16, and the seventeenth capacitor C17 are all connected to the opposite-named terminal of the first stage coil; the opposite-named terminal of the first stage coil is grounded; The cathode of the eighth diode D8 is connected to one end of the twenty-second resistor R22, and the other end of the twenty-second resistor R22 is connected to the first input terminal of the third optocoupler U3. The first output terminal of the third optocoupler U3 is connected to the first pin of the three-terminal regulator U4 and one end of the eighteenth capacitor C18. The other end of the eighteenth capacitor C18 is connected to the second pin of the three-terminal regulator U4, and the third pin of the three-terminal regulator U4 is grounded. The twenty-third resistor R23 is connected in parallel to the first input terminal and the first output terminal of the third optocoupler U3. The 24th resistor R24, the 25th resistor R25, and the 26th resistor R26 are connected in series. One end of the 24th resistor R24 ​​is connected to the end of the 16th capacitor C16 that is connected to the 8th diode D8. One end of the 26th resistor R26 is grounded. The end of the 26th resistor R26 and the 25th resistor R25 connected in series is connected to the second pin of the three-terminal regulator U4. The same-name terminal of the second-stage coil is connected to the anode of the ninth diode D9. The cathode of the ninth diode D9 is connected to the second voltage output port OUT2, the input pin of the rectifier chip U5, and one end of the nineteenth capacitor C19. The other end of the nineteenth capacitor C19, the opposite-name terminal of the second-stage coil, and the ground pin of the rectifier chip U5 are all grounded. The output pin of the rectifier chip U5 is connected to the twentieth capacitor C20, the twenty-first capacitor C21, and the third voltage output port OUT3. The other ends of the twentieth capacitor C20 and the twenty-first capacitor C21 are both grounded. The same-name terminal of the third-stage coil is connected to the anode of the tenth diode D10, and the cathode of the tenth diode D10 is connected to one end of the twelfth capacitor C22 and the second input terminal of the third optocoupler U3; the opposite-name terminal of the third-stage coil and the other end of the twelfth capacitor C22 are both connected to the signal ground terminal. The second output terminal of the third optocoupler U3 is connected to one end of the twenty-seventh resistor R27, one end of the twenty-third capacitor C23, and the feedback pin of the power control chip U0; the other end of the twenty-seventh resistor R27 is connected to one end of the twenty-fourth capacitor C24, and the other ends of the twenty-third capacitor C23 and the twenty-fourth capacitor C24 are both connected to the signal ground terminal; the frequency control pin of the power control chip U0 is connected to the feedback pin of the power control chip U0.

[0019] By adopting the above technical solution, the power supply circuit uses a power control chip, which on the one hand helps to simplify the circuit, reduce the size of the power supply circuit, and reduce costs; on the other hand, the power control chip is used to receive feedback voltage and stabilize the output voltage according to the feedback voltage.

[0020] Secondly, the control system for a cooling water tank of an argon welding machine provided in this application adopts the following technical solution: A control system for a cooling water tank for an argon welding machine includes a control module and the aforementioned control circuit. The signal input terminal of the control module is connected to the signal output terminal of the control circuit, and the signal output terminal of the control module is connected to the signal input terminal of the control circuit. The control module is used to receive the temperature signal transmitted by the control circuit and output alarm information when the temperature signal exceeds the preset temperature threshold. The control module is also used to receive the switch closing signal transmitted by the control circuit and output closing success information or start signal after receiving the switch closing signal to control the coil of the water tank relay to be energized.

[0021] By adopting the above technical solution, after the welding torch is connected to the cooling water tank, the worker can be notified through the control module; the worker can also be notified of changes in the temperature of the cooling water tank through the control module. In addition, the power-on and power-off of the cooling water tank can be controlled through the control module, which helps to improve the ease of use of the cooling water tank.

[0022] In summary, by setting up temperature detection circuits and switch detection circuits to monitor the status of the cooling water tank, the switch detection circuit transmits a switch closure signal to the host computer after the welding torch is connected to the cooling water tank; when the temperature of the cooling water tank changes, the temperature detection circuit transmits a temperature signal to the host computer, allowing workers to know the status of the cooling water tank in a timely manner without having to perform the inspection themselves, thus improving the ease of use of the cooling water tank. Attached Figure Description

[0023] Figure 1 This is a structural block diagram of a control system for a cooling water tank for an argon welding machine according to an embodiment of this application.

[0024] Figure 2 This is a circuit diagram of the interface circuit, temperature detection circuit, and switch detection circuit of the control circuit for a cooling water tank for an argon welding machine according to an embodiment of this application.

[0025] Figure 3 This is a circuit diagram of the power supply circuit of the control circuit for a cooling water tank for an argon welding machine according to an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures: 1. Control module; 2. Control circuit; 21. Interface circuit; 22. Temperature detection circuit; 23. Switch detection circuit; 24. Power supply circuit; 25. Water tank power supply control circuit. Detailed Implementation

[0027] This application discloses a control system for a cooling water tank of an argon welding machine. (Refer to...) Figure 1The system includes a control module 1 and a control circuit 2. The signal input terminal of the control module 1 is connected to the signal output terminal of the control circuit 2, and the signal output terminal of the control module 1 is connected to the signal input terminal of the control circuit 2. The control circuit 2 is used to detect the temperature change of the cooling water tank of the argon welding machine and the connection status between the cooling water tank and the welding torch, and transmits temperature signals and switch closing signals to the control module 1.

[0028] The control module 1 receives the temperature signal transmitted by the control circuit 2 and outputs an alarm message when the temperature signal exceeds a preset temperature threshold. It should be noted that the temperature signal can be a voltage signal or a current signal; the temperature threshold is set based on the actual conditions of the cooling water tank, and in this embodiment, the temperature threshold is set to 70 degrees Celsius. This is intended to output an alarm message before the cooling water tank malfunctions due to overheating. The alarm message can be sound and / or light, or it can be text displayed on a screen. It is easy to understand that when the alarm message is sound, the control module 1 is equipped with a sound alarm; when the alarm message is light, the control module 1 is equipped with a light alarm; when the alarm message is both sound and light, the control module 1 is equipped with an audible and visual alarm; and when the alarm message is text, the control module 1 is equipped with a display screen.

[0029] The control module 1 is also used to receive the switch closure signal transmitted by the control circuit 2, and output a closure success message or a start signal after receiving the switch closure signal. After the control module 1 outputs the start signal, the control circuit 2 controls the coil of the water tank relay to be energized.

[0030] The control module 1 can be a PLC controller, a microcontroller, or an MCU. In this embodiment, the control module 1 is equipped with a display screen and a human-machine interaction module, which makes it convenient for workers to view the information fed back by the control circuit 2.

[0031] The control circuit will now be described in detail based on the control system described above.

[0032] A control circuit for a cooling water tank of an argon welding machine, referring to Figure 2 and Figure 3 It includes an interface circuit 21, a temperature detection circuit 22, a switch detection circuit 23, and a power supply circuit 24. The power supply circuit 24 provides operating voltage to the temperature detection circuit 22 and the switch detection circuit 23. The interface circuit 21 connects to and communicates with the display and control panel; it is easy to understand that the display and control panel is the aforementioned control module 1. The temperature detection circuit 22 is connected to the interface circuit 21 and reflects the temperature changes of the cooling water tank, transmitting temperature signals to the interface circuit 21 based on these temperature changes.

[0033] It should be noted that the temperature change referred to in this embodiment includes three cases: the temperature change amplitude is zero, greater than zero, and less than zero. That is, regardless of whether the temperature of the cooling water tank changes, the temperature detection circuit 22 transmits the temperature signal to the interface circuit 21 in real time.

[0034] Reference Figure 2 The switch detection circuit 23 is connected to the interface circuit 21 and is used to transmit a switch closure signal to the interface circuit 21 when the cooling water tank is connected to the welding torch. Specifically, the interface circuit 21 includes a first interface pin M1, a second interface pin M2, a third interface pin M3, a fourth interface pin M4, a fifth interface pin M5, and a sixth interface pin M6. In this embodiment, the sixth interface pin M6 is not used; and the first interface pin M1 is used to receive and transmit a temperature signal to the display and control panel; the second interface pin M2 is used to transmit an input voltage; the third interface pin M3 is a ground pin; the fourth interface pin M4 is connected to the control signal output terminal of the display and control panel and is used to receive the control signal output by the display and control panel; the fifth interface pin M5 is used to receive and transmit a switch closure signal to the display and control panel.

[0035] Reference Figure 2 The temperature detection circuit 22 includes a temperature detection voltage input terminal VINa, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a third diode D3, a thermistor R0, a first common-mode inductor L1, and a second common-mode inductor L2. The thermistor R0 is used to reflect temperature changes in the cooling water tank and can be installed inside the cooling water tank housing, or on the radiator or power device of the cooling water tank. Its purpose is to ensure that the resistance value of the thermistor R0 changes when the temperature of the cooling water tank changes.

[0036] One end of the first capacitor C1 is connected to the temperature detection voltage input terminal VINa, and the other end is grounded. The temperature detection voltage input terminal VINa receives DC current, and the first capacitor C1 acts as a filter. One end of the first resistor R1 is connected to the temperature detection voltage input terminal VINa, and the other end is connected to the first node P1. One end of the second capacitor C2 is connected to the first node P1, and the other end is grounded. One end of the first coil of the first common-mode inductor L1 is connected to the first node P1, and the other end is connected to the first pin N1. One end of the second coil of the first common-mode inductor L1 is connected to the second pin N2, and the other end is connected to the grounded end of the second capacitor C2. The two ends of the thermistor R0 are connected to the first pin N1 and the second pin N2, respectively.

[0037] The third capacitor C3 is connected in parallel with the second capacitor C2, meaning one end of the third capacitor C3 is connected to the first node P1, and the other end is connected to the ground terminal of the second capacitor C2. One end of the second resistor R2 is connected to the first node P1, and the other end is connected to one end of the first coil of the second common-mode inductor L2. The cathode of the first diode D1 is connected to the temperature detection voltage input terminal VINa, and the anode is connected to the line connecting the second resistor R2 and the first node P1, forming the second node P2. The cathode of the second diode D2 is connected to the second node P2, and the anode is grounded. The first diode D1 and the second diode D2 form a clamping diode to stabilize the voltage at the second node P2. The cathode of the third diode D3 is connected to the end of the second resistor R2 away from the second node P2, and the anode is connected to the ground terminal of the second capacitor C2. One end of the fourth capacitor C4 is connected to the end of the second resistor R2 away from the second node P2, and the other end is connected to the ground terminal of the second capacitor C2; that is, the third diode D3 and the fourth capacitor C4 are connected in parallel.

[0038] The other end of the first coil of the second common-mode inductor L2, that is, the end away from the second resistor R2, is connected to the first interface pin M1 of the interface circuit 21; one end of the second coil of the second common-mode inductor L2 is grounded, and the other end is connected to the ground terminal of the interface circuit 21, that is, the third interface pin M3 of the interface circuit 21.

[0039] Reference Figure 2 The switch detection circuit 23 includes a third pin N3, a fourth pin N4, a fifth capacitor C5, a sixth capacitor C6, a fourth diode D4, a fifth diode D5, a third resistor R3, a fourth resistor R4, a first optocoupler U1, a first voltage input terminal VINb for switch detection, and a second voltage input terminal VINc for switch detection. The third pin N3 and the fourth pin N4 are used to connect to the water tank switch. When the water tank switch is closed, the third pin N3 and the fourth pin N4 are connected; when the water tank switch is open, the third pin N3 and the fourth pin N4 are disconnected. It should be noted that after the cooling water tank is connected to the welding torch, the water tank switch automatically closes. This is a feature of existing cooling water tank structures and will not be elaborated further.

[0040] One end of the third pin N3 is grounded. The fourth pin N4 is connected to the cathodes of both the fourth diode D4 and the fifth diode D5. The two ends of the fifth capacitor C5 are connected to the ground terminal of the third pin N3 and the fourth pin N4, respectively. The anode of the fourth diode D4 is grounded. The anode of the fifth diode D5 is connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the first output terminal of the first optocoupler U1. The first voltage input terminal VINb of the switch detection is connected to the first input terminal of the first optocoupler U1. After the third pin N3 and the fourth pin N4 are connected, the current input to the first voltage input terminal VINb of the switch detection enters from the first input terminal of the first optocoupler U1, flows out from the first output terminal, and then flows sequentially through the third resistor R3, the fifth diode D5, the fourth pin N4, and the third pin N3 before entering ground.

[0041] The second output terminal of the first optocoupler U1 is grounded, and the third output terminal of the first optocoupler U1 is connected to the fifth interface pin M5 of the interface circuit 21 for transmitting a switch closing signal to the interface circuit 21. Specifically, after current flows between the first input terminal and the first output terminal of the first optocoupler U1, the third output terminal generates a low-level signal, which is transmitted to the display and control panel through the fifth interface pin M5.

[0042] The two ends of the sixth capacitor C6 are connected to the second and third output terminals of the first optocoupler U1, respectively; the second voltage input terminal VINc for switch detection is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the third output terminal of the first optocoupler U1. The second voltage input terminal VINc for switch detection is used to input DC power, and the fourth resistor R4 is a pull-up resistor used to improve the stability of low-level signals.

[0043] The fourth interface pin M4 of interface circuit 21 is connected to the water tank power supply control circuit 25, which is used to control the power-on and power-off of the water tank. For details, please refer to... Figure 2 The water tank power supply control circuit 25 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a transistor Q1, a MOSFET Q2, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a sixth diode D6, a second optocoupler U2, a first power supply control voltage input terminal VINd, a second power supply control voltage input terminal VINe, a third power supply control voltage input terminal VINf, and a fourth power supply control voltage input terminal VINg.

[0044] One end of the fifth resistor R5 is connected to the fourth interface pin M4 of interface circuit 21, and the other end is connected to one end of the sixth resistor R6 and the base of transistor Q1; the other end of the sixth resistor R6 and the emitter of transistor Q1 are both grounded. The collector of transistor Q1 is connected to the first output terminal of the second optocoupler U2; the first input terminal of the second optocoupler U2 is connected to one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the first voltage input terminal VINd for power supply control. After the display control panel transmits a control signal to the fourth interface pin M4, the control signal flows through the fifth resistor R5 and reaches the base of transistor Q1, making the collector of transistor Q1 conduct with the transmitter. The DC current input to the first voltage input terminal VINd for power supply control flows through the first input terminal and the first output terminal of the second optocoupler U2.

[0045] The second voltage input terminal VINe of the power supply control is connected to the second input terminal of the second optocoupler U2. One end of the seventh capacitor C7 is connected to the second voltage input terminal VINe, and the other end is grounded. The second output terminal of the second optocoupler U2 is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the eighth capacitor C8, one end of the ninth resistor R9, and the gate of the MOSFET Q2. The other ends of the eighth capacitor C8, the other ends of the ninth resistor R9, and the source of the MOSFET Q2 are all grounded.

[0046] The third voltage input terminal VINf of the power supply control is connected to the input terminal of the water tank relay coil, and the drain of MOSFET Q2 is connected to the output terminal of the water tank relay coil. The anode of the sixth diode D6 is connected to the output terminal of the water tank relay coil, and the cathode is connected to the input terminal of the water tank relay coil. After current flows through the first input and first output terminals of the second optocoupler U2, the second input and second output terminals are turned on, allowing the DC current input at the second voltage input terminal VINe to reach the gate of MOSFET Q2. The drain and source of MOSFET Q2 are turned on, allowing the DC current input at the third voltage input terminal VINf of the power supply control to flow through the water tank relay coil, i.e., the coil is energized.

[0047] The fourth voltage input terminal VINg of the power supply control is connected to the moving contact terminal of the water tank relay, and the stationary contact terminal of the water tank relay is connected to the power supply pin F1. One end of the tenth resistor R10 is connected to the moving contact terminal of the water tank relay, and the other end is connected to one end of the ninth capacitor C9. The other end of the ninth capacitor C9 is connected to the moving contact terminal of the water tank relay. After the water tank relay coil is energized, the armature actuates, and the stationary contact and moving contact make contact. The DC power input from the fourth voltage input terminal VINg of the power supply control is transmitted to the water pump and radiator of the cooling water tank through the power supply pin F1.

[0048] Reference Figure 2The control circuit for the cooling water tank of the argon welding machine also includes a power supply control voltage output terminal VINh and a tenth capacitor C10. The power supply control voltage output terminal VINh is connected to both the second interface pin M2 and one end of the tenth capacitor C10, while the other end of the tenth capacitor C10 is connected to the third interface pin M3. The power supply control voltage output terminal VINh is used to output the DC voltage transmitted from the second interface pin M2; the tenth capacitor C10 acts as a filter.

[0049] Reference Figure 3 The power supply circuit 24 includes the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, the twenty-fourth resistor R24, the twenty-fifth resistor R25, the twenty-sixth resistor R26, the twenty-seventh resistor R27, the eleventh capacitor C11, the twelfth capacitor C12, the thirteenth capacitor C13, the fourteenth capacitor C14, and the fifteenth capacitor C15. Capacitor C15, sixteenth capacitor C16, seventeenth capacitor C17, eighteenth capacitor C18, nineteenth capacitor C19, twentieth capacitor C20, twenty-first capacitor C21, twenty-second capacitor C22, twenty-third capacitor C23, twenty-fourth capacitor C24, seventh diode D7, eighth diode D8, ninth diode D9, tenth diode D10, primary coil, first stage coil, second stage coil, third stage coil, power control chip U0, third optocoupler U3, three-terminal regulator U4, rectifier chip U5, first voltage output port OUT1, second voltage output port OUT2 and third voltage output port OUT3.

[0050] The primary coil, the first-stage coil, the second-stage coil, and the third-stage coil are all wound on a magnetic core. The primary coil is wound on one side of the magnetic core, while the first-stage coil, the second-stage coil, and the third-stage coil are wound on the other side of the magnetic core, forming a transformer structure.

[0051] One end of the eleventh resistor R11 is connected to the power input terminal of the power supply circuit 24, and the other end is connected to the corresponding terminal of the primary coil. One end of the eleventh capacitor C11, one end of the twelfth resistor R12, one end of the seventeenth resistor R17, and one end of the eighteenth resistor R18 are all connected to the corresponding terminal of the primary coil. The other end of the eleventh capacitor C11 is connected to the signal ground terminal; the other end of the twelfth resistor R12 is connected in series with the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor R16. One end of the sixteenth resistor R16 is connected to the voltage input pin 2 of the power control chip U0; the other ends of the twelfth capacitor C12, the seventeenth resistor R17, and the eighteenth resistor R18 are all connected to one end of the nineteenth resistor R19. The other end of the nineteenth resistor R19 is connected to the cathode of the seventh diode D7; the anode of the seventh diode D7 is connected to the opposite terminal of the primary coil and the signal input pin 7 of the power control chip U0; the signal output pin 4 and the ground pin 3 of the power control chip U0 are both connected to the signal ground terminal.

[0052] The seventh diode D7, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, and the twelfth capacitor C12 are used to absorb the voltage spikes generated by the power control chip U0. The power control chip U0 is a TOP249 series chip, which has an internal MOSFET. In this embodiment, the signal input pin 7 of the power control chip U0 is connected to the drain of the internal MOSFET; the signal output pin 4 of the power control chip U0 is connected to the source of the internal MOSFET.

[0053] Reference Figure 3 One end of the thirteenth capacitor C13 is connected to the same-name terminal of the primary coil, and the other end is connected to the opposite-name terminal of the primary coil. The same-name terminal of the primary coil is connected to the anode of the eighth diode D8. The cathode of the eighth diode D8 is connected to the first voltage output port OUT1. After rectification by the eighth diode D8, DC power is output from the first voltage output port OUT1. The anode and cathode of the eighth diode D8 are connected in parallel with the twentieth resistor R20 and the fourteenth capacitor C14, which are connected in series. One end of the fifteenth capacitor C15 is connected to the cathode of the eighth diode D8, and the other end is connected to the opposite-name terminal of the primary coil. One end of the twenty-first resistor R21, one end of the sixteenth capacitor C16, and one end of the seventeenth capacitor C17 are all connected to the cathode of the eighth diode D8; the other ends of the twenty-first resistor R21, the sixteenth capacitor C16, and the seventeenth capacitor C17 are all connected to the opposite-name terminal of the primary coil, which is grounded.

[0054] The cathode of the eighth diode D8 is connected to one end of the twenty-second resistor R22. The other end of the twenty-second resistor R22 is connected to the first input terminal of the third optocoupler U3. The first output terminal of the third optocoupler U3 is connected to the first pin of the three-terminal regulator U4 and one end of the eighteenth capacitor C18. The other end of the eighteenth capacitor C18 is connected to the second pin of the three-terminal regulator U4, and the third pin of the three-terminal regulator U4 is grounded. The twenty-third resistor R23 is connected in parallel between the first input terminal and the first output terminal of the third optocoupler U3. The current flowing through the first input terminal and the first output terminal of the third optocoupler U3 makes the second input terminal and the second output terminal of the third optocoupler U3 conduct.

[0055] The twenty-fourth resistor R24, the twenty-fifth resistor R25, and the twenty-sixth resistor R26 are connected in series. One end of the twenty-fourth resistor R24 ​​is connected to the end of the sixteenth capacitor C16 that is connected to the eighth diode D8. One end of the twenty-sixth resistor R26 is grounded. The end of the series connection between the twenty-sixth resistor R26 and the twenty-fifth resistor R25 is connected to the second pin of the three-terminal voltage regulator U4.

[0056] The same-name terminal of the second-stage coil is connected to the anode of the ninth diode D9. The cathode of the ninth diode D9 is connected to the second voltage output port OUT2, the input pin of the rectifier chip U5, and one end of the nineteenth capacitor C19. The other end of the nineteenth capacitor C19, the opposite-name terminal of the second-stage coil, and the ground pin of the rectifier chip U5 are all grounded. The output pin of the rectifier chip U5 is connected to the twentieth capacitor C20, the twenty-first capacitor C21, and the third voltage output port OUT3; the other ends of the twentieth capacitor C20 and the twenty-first capacitor C21 are both grounded. After rectification by the ninth diode D9, the second voltage output port OUT2 outputs DC power. Furthermore, the DC power flowing through the ninth diode D9 is reduced in voltage after passing through the rectifier chip U5 and is output from the third voltage output port OUT3.

[0057] The same-name terminal of the third-stage coil is connected to the anode of the tenth diode D10. The cathode of the tenth diode D10 is connected to one end of the twenty-second capacitor C22 and the second input terminal of the third optocoupler U3. The opposite-name terminal of the third-stage coil and the other end of the twenty-second capacitor C22 are both connected to the signal ground terminal. The second output terminal of the third optocoupler U3 is connected to one end of the twenty-seventh resistor R27, one end of the twenty-third capacitor C23, and the feedback pin of the power control chip U0. The other end of the twenty-seventh resistor R27 is connected to one end of the twenty-fourth capacitor C24. The other ends of the twenty-third capacitor C23 and the twenty-fourth capacitor C24 are both connected to the signal ground terminal. The frequency control pin of the power control chip U0 is connected to the feedback pin of the power control chip U0.

[0058] It should be noted that, to enhance circuit isolation, in this embodiment, the input voltages of the temperature detection voltage input terminal VINa, the switch detection first voltage input terminal VINb, and the power supply control second voltage input terminal VINe are all provided by the third voltage output port OUT3, and are 15V DC; the input voltages of the switch detection second voltage input terminal VINc and the power supply control first voltage input terminal VINd are both provided by the power supply control voltage output terminal VINh, and are 15V DC. In actual circuit design, the switch detection second voltage input terminal VINc and the power supply control first voltage input terminal VINd can be two voltage input ports or a single voltage input port. The input voltage of the power supply control third voltage input terminal VINf is provided by the second voltage output port OUT2, and is 24V DC; the input voltage of the power supply control fourth voltage input terminal VINg is provided by the first voltage output port OUT1, and is 24V DC.

[0059] The implementation principle of the control system for a cooling water tank of an argon welding machine according to an embodiment of this application is as follows: The temperature detection circuit 22 transmits the temperature signal in real time to the display and control panel via the interface circuit 21. The display and control panel displays the temperature signal, allowing workers to easily know the temperature status of the cooling water tank, which helps improve the ease of use, safety, and service life of the cooling water tank. After the cooling water tank is connected to the welding torch, the switch detection circuit 23 transmits the switch closure signal to the display and control panel via the interface circuit 21, allowing workers to know the connection status between the cooling water tank and the welding torch, thereby controlling the power supply status of the cooling water tank.

[0060] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A control circuit for a cooling water tank of an argon welding machine, characterized in that, include: Interface circuit (21) is used to connect to the display and control panel and communicate with the display and control panel; Temperature detection circuit (22) is connected to interface circuit (21) to reflect the temperature change of cooling water tank and transmit temperature signal to interface circuit (21) based on the temperature change of cooling water tank; A switch detection circuit (23) is connected to the interface circuit (21) and is used to transmit a switch closing signal to the interface circuit (21) when the cooling water tank is connected to the welding gun. and, A power supply circuit (24) is used to provide operating voltage for the temperature detection circuit (22) and the switch detection circuit (23); The temperature detection circuit (22) includes a temperature detection voltage input terminal VINa, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a third diode D3, and a thermistor R0. One end of the first capacitor C1 is connected to the temperature detection voltage input terminal VINa, and the other end is grounded; one end of the first resistor R1 is connected to the temperature detection voltage input terminal VINa, and the other end of the first resistor R1 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is grounded; one end of the second capacitor C2 connected to the first resistor R1 is connected to a first pin N1, and the grounded end of the second capacitor C2 is connected to a second pin N2; one end of the thermistor R0 is connected to the first pin N1, and the other end is connected to the second pin N2; the third capacitor C3 is connected in parallel with the second capacitor C2; one end of the second resistor R2 is connected to the second capacitor C2 and the first... One end of resistor R1 is connected to the interface circuit (21), and the other end is connected to the interface circuit (21); the cathode of the first diode D1 is connected to the temperature detection voltage input terminal VINa, and the anode is connected to the end of the second resistor R2 and the second capacitor C2; the cathode of the second diode D2 is connected to the end of the second resistor R2 and the second capacitor C2, and the anode is grounded; the cathode of the third diode D3 is connected to the end of the second resistor R2 and the interface circuit (21), and the anode is connected to the end of the second capacitor C2 that is grounded; one end of the fourth capacitor C4 is connected to the end of the second resistor R2 and the interface circuit (21), and the other end is connected to the end of the second capacitor C2 that is grounded.

2. The control circuit for a cooling water tank for an argon welding machine according to claim 1, characterized in that: The temperature detection circuit (22) also includes a first common-mode inductor L1 and a second common-mode inductor L2; One end of the first coil of the first common-mode inductor L1 is connected to the first pin N1, and the other end is connected to the end of the second capacitor C2 and the first resistor R1; one end of the second coil of the first common-mode inductor L1 is connected to the second pin N2, and the other end is connected to the end of the second capacitor C2 that is grounded; The first coil of the second common-mode inductor L2 is connected in series between the second resistor R2 and the interface circuit (21); one end of the second coil of the second common-mode inductor L2 is grounded, and the other end is connected to the ground terminal of the interface circuit (21).

3. The control circuit for a cooling water tank for an argon welding machine according to claim 1, characterized in that: The switch detection circuit (23) includes a third pin N3, a fourth pin N4, a fifth capacitor C5, a sixth capacitor C6, a fourth diode D4, a fifth diode D5, a third resistor R3, a fourth resistor R4, a first optocoupler U1, a first voltage input terminal VINb for switch detection, and a second voltage input terminal VINc for switch detection. The third pin N3 and the fourth pin N4 are used to connect to the water tank switch. When the water tank switch is closed, the third pin N3 and the fourth pin N4 are connected; when the water tank switch is open, the third pin N3 and the fourth pin N4 are disconnected. The third pin N3 is grounded, and the fourth pin N4 is connected to the cathodes of the fourth diode D4 and the fifth diode D5. The two ends of the fifth capacitor C5 are connected to the ground terminal of the third pin N3 and the fourth pin N4, respectively. The anode of the fourth diode D4 is grounded. The anode of the fifth diode D5 is connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the first output terminal of the first optocoupler U1. The first voltage input terminal VINb of the switch detection is connected to the first input terminal of the first optocoupler U1. The second output terminal of the first optocoupler U1 is grounded, and the third output terminal of the first optocoupler U1 is connected to the interface circuit (21) for transmitting a switch closing signal to the interface circuit (21). The two ends of the sixth capacitor C6 are respectively connected to the second output terminal and the third output terminal of the first optocoupler U1; the second voltage input terminal VINc of the switch detection is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the third output terminal of the first optocoupler U1.

4. The control circuit for a cooling water tank for an argon welding machine according to claim 1, characterized in that: The interface circuit (21) is also connected to the water tank power supply control circuit (25), which is used to control the power on and power off of the water tank.

5. The control circuit for a cooling water tank for an argon welding machine according to claim 4, characterized in that: The water tank power supply control circuit (25) includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a transistor Q1, a MOSFET Q2, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a sixth diode D6, a second optocoupler U2, a first power supply control voltage input terminal VINd, a second power supply control voltage input terminal VINe, a third power supply control voltage input terminal VINf, and a fourth power supply control voltage input terminal VINg. One end of the fifth resistor R5 is connected to the interface circuit (21), and the other end is connected to one end of the sixth resistor R6 and the base of the transistor Q1; the other end of the sixth resistor R6 and the emitter of the transistor Q1 are both grounded; the collector of the transistor Q1 is connected to the first output terminal of the second optocoupler U2; the first input terminal of the second optocoupler U2 is connected to one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the first voltage input terminal VINd of the power supply control. The second voltage input terminal VINe of the power supply control is connected to the second input terminal of the second optocoupler U2. One end of the seventh capacitor C7 is connected to the second voltage input terminal VINe of the power supply control, and the other end is grounded. The second output terminal of the second optocoupler U2 is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the eighth capacitor C8, one end of the ninth resistor R9, and the gate of the MOS transistor Q2. The other end of the eighth capacitor C8, the other end of the ninth resistor R9, and the source of the MOS transistor Q2 are all grounded. The third voltage input terminal VINf of the power supply control is connected to the input terminal of the water tank relay coil. The drain of the MOS transistor Q2 is connected to the output terminal of the water tank relay coil. The anode of the sixth diode D6 is connected to the output terminal of the water tank relay coil, and the cathode is connected to the input terminal of the water tank relay coil. The fourth voltage input terminal VINg of the power supply control is connected to the moving contact terminal of the water tank relay, and the stationary contact terminal of the water tank relay is connected to the power supply pin; one end of the tenth resistor R10 is connected to the moving contact terminal of the water tank relay, and the other end is connected to one end of the ninth capacitor C9; the other end of the ninth capacitor C9 is connected to the moving contact terminal of the water tank relay.

6. The control circuit for a cooling water tank for an argon welding machine according to claim 1, characterized in that: The power supply circuit (24) includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C ... capacitor C15, a sixteenth resistor R16, a seventeenth resistor R17, a eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, an eleven Capacitor C15, sixteenth capacitor C16, seventeenth capacitor C17, eighteenth capacitor C18, nineteenth capacitor C19, twentieth capacitor C20, twenty-first capacitor C21, twenty-second capacitor C22, twenty-third capacitor C23, twenty-fourth capacitor C24, seventh diode D7, eighth diode D8, ninth diode D9, tenth diode D10, primary coil, first stage coil, second stage coil, third stage coil, power control chip U0, third optocoupler U3, three-terminal regulator U4, rectifier chip U5, first voltage output port OUT1, second voltage output port OUT2 and third voltage output port OUT3; The primary coil, the first secondary coil, the second secondary coil, and the third secondary coil are all wound on a magnetic core. The primary coil is wound on one side of the magnetic core, and the first secondary coil, the second secondary coil, and the third secondary coil are wound on the other side of the magnetic core to form a transformer. One end of the eleventh resistor R11 is connected to the power input terminal of the power supply circuit (24), and the other end is connected to the corresponding terminal of the primary coil; one end of the eleventh capacitor C11, one end of the twelfth resistor R12, one end of the seventeenth resistor R17, and one end of the eighteenth resistor R18 are all connected to the corresponding terminal of the primary coil; the other end of the eleventh capacitor C11 is connected to the signal ground terminal; the other end of the twelfth resistor R12 is connected in series with the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor. R16, one end of the sixteenth resistor R16 is connected to the voltage input pin of the power control chip U0; the other ends of the twelfth capacitor C12, the seventeenth resistor R17, and the eighteenth resistor R18 are all connected to one end of the nineteenth resistor R19; the other end of the nineteenth resistor R19 is connected to the cathode of the seventh diode D7; the anode of the seventh diode D7 is connected to the opposite-name terminal of the primary coil and the signal input pin of the power control chip U0; the signal output pin and ground pin of the power control chip U0 are both connected to the signal ground terminal; One end of the thirteenth capacitor C13 is connected to the same-name terminal of the primary coil, and the other end is connected to the opposite-name terminal of the first primary coil; the same-name terminal of the first primary coil is connected to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is connected to the first voltage output port OUT1; the anode and cathode of the eighth diode D8 are connected in parallel with a twentieth resistor R20 and a fourteenth capacitor C14 arranged in series. One end of the fifteenth capacitor C15 is connected to the cathode of the eighth diode D8, and the other end is connected to the opposite-named terminal of the first stage coil; one end of the twenty-first resistor R21, one end of the sixteenth capacitor C16, and one end of the seventeenth capacitor C17 are all connected to the cathode of the eighth diode D8; the other ends of the twenty-first resistor R21, the sixteenth capacitor C16, and the seventeenth capacitor C17 are all connected to the opposite-named terminal of the first stage coil; the opposite-named terminal of the first stage coil is grounded; The cathode of the eighth diode D8 is connected to one end of the twenty-second resistor R22, and the other end of the twenty-second resistor R22 is connected to the first input terminal of the third optocoupler U3. The first output terminal of the third optocoupler U3 is connected to the first pin of the three-terminal regulator U4 and one end of the eighteenth capacitor C18. The other end of the eighteenth capacitor C18 is connected to the second pin of the three-terminal regulator U4, and the third pin of the three-terminal regulator U4 is grounded. The twenty-third resistor R23 is connected in parallel to the first input terminal and the first output terminal of the third optocoupler U3. The 24th resistor R24, the 25th resistor R25, and the 26th resistor R26 are connected in series. One end of the 24th resistor R24 ​​is connected to the end of the 16th capacitor C16 that is connected to the 8th diode D8. One end of the 26th resistor R26 is grounded. The end of the 26th resistor R26 and the 25th resistor R25 connected in series is connected to the second pin of the three-terminal regulator U4. The same-name terminal of the second-stage coil is connected to the anode of the ninth diode D9. The cathode of the ninth diode D9 is connected to the second voltage output port OUT2, the input pin of the rectifier chip U5, and one end of the nineteenth capacitor C19. The other end of the nineteenth capacitor C19, the opposite-name terminal of the second-stage coil, and the ground pin of the rectifier chip U5 are all grounded. The output pin of the rectifier chip U5 is connected to the twentieth capacitor C20, the twenty-first capacitor C21, and the third voltage output port OUT3. The other ends of the twentieth capacitor C20 and the twenty-first capacitor C21 are both grounded. The same-name terminal of the third-stage coil is connected to the anode of the tenth diode D10, and the cathode of the tenth diode D10 is connected to one end of the twelfth capacitor C22 and the second input terminal of the third optocoupler U3; the opposite-name terminal of the third-stage coil and the other end of the twelfth capacitor C22 are both connected to the signal ground terminal. The second output terminal of the third optocoupler U3 is connected to one end of the twenty-seventh resistor R27, one end of the twenty-third capacitor C23, and the feedback pin of the power control chip U0; the other end of the twenty-seventh resistor R27 is connected to one end of the twenty-fourth capacitor C24, and the other ends of the twenty-third capacitor C23 and the twenty-fourth capacitor C24 are both connected to the signal ground terminal; the frequency control pin of the power control chip U0 is connected to the feedback pin of the power control chip U0.

7. A control system for a cooling water tank of an argon welding machine, characterized in that: It includes a control module (1) and a control circuit (2) according to any one of claims 1-6; The signal input terminal of the control module (1) is connected to the signal output terminal of the control circuit (2), and the signal output terminal of the control module (1) is connected to the signal input terminal of the control circuit (2); the control module (1) is used to receive the temperature signal transmitted by the control circuit (2), and output alarm information when the temperature signal exceeds the preset temperature threshold; The control module (1) is also used to receive the switch closing signal transmitted by the control circuit (2), and output a closing success message or a start signal after receiving the switch closing signal, and control the coil of the water tank relay to be energized.

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