Voltage pre-display and real display switching system and wire feeder

Abstract

The utility model discloses a voltage pre-display and real display switching system and a wire feeder. The voltage pre-display and real display switching system comprises a first switch unit, a second switch unit, a first voltage regulating unit and a second voltage regulating unit, when no load exists, the second switch unit and the first voltage adjusting unit are switched on, the first switch unit and the second voltage adjusting unit are switched off, and an input first signal is displayed through the first voltage adjusting unit. When a load is loaded, the second switch unit and the first voltage regulation unit are switched off, the first switch unit and the second voltage regulation unit are switched on, and an input second signal is displayed through the second voltage regulation unit. According to the utility model, the first switch unit and the second switch unit are arranged, and the first signal and the second signal are respectively processed by controlling the on-off of the first switch unit and the second switch unit, so that the simultaneous processing of pre-display and real display on the same line is avoided, the classification of the input voltage and the prefabricated voltage of the welding machine is realized, and the 1: 1 display is completed.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a voltage pre-display and real-display switching system and a wire feeder. Background Art

[0002] In the prior art, when a wire feeder is used, the required voltage is generally pre-set on the welding machine; during actual operation, the actual voltage is displayed on the panel.

[0003] However, in actual operation, the voltage pre-display and actual display of the wire feeder cannot achieve a high degree of fit of 1:1, that is, there is a difference between the pre-display and the actual display, which makes it unclear to the user which displayed voltage to use as a reference for the next adjustment. Summary of the invention

[0004] Aiming at the technical problem of inconsistency between voltage pre-display and actual display in the prior art, the utility model provides a voltage pre-display and actual display switching system and a wire feeder.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A voltage pre-display and real-display switching system comprises a first switch unit, a second switch unit, a first voltage regulating unit and a second voltage regulating unit;

[0007] When no-load, the second switch unit and the first voltage regulating unit are turned on, the first switch unit and the second voltage regulating unit are turned off, and the input first signal is displayed after passing through the first voltage regulating unit;

[0008] When the load is on, the second switch unit and the first voltage regulating unit are turned off, the first switch unit and the second voltage regulating unit are turned on, and the input second signal is displayed after passing through the second voltage regulating unit.

[0009] Preferably, it also includes a first signal input unit and a second signal input unit;

[0010] The output end of the first signal input unit is connected to the input end of the first switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit respectively; the output end of the second signal input unit is connected to the input end of the second switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit respectively; the output end of the first voltage regulating unit and the output end of the second voltage regulating unit are connected in parallel to the input end of the voltage display unit; the output end of the first switch unit is grounded, and the output end of the second switch unit is grounded.

[0011] Preferably, the first signal input unit comprises a first voltage follower (U1) and a second comparator (U2):

[0012] The first signal input terminal is connected to one end of the seventh resistor (R7), the other end of the seventh resistor (R7) is connected to one end of the sixth resistor (R6) and the control terminal, the other end of the sixth resistor (R6) is respectively connected to the cathode of the first diode (D1), one end of the fifth resistor (R5), the collector of the third transistor (Q3), and the non-phase input terminal of the first voltage follower (U1); the anode of the first diode (D1) is grounded, and the other end of the fifth resistor (R5) is grounded;

[0013] The negative phase input terminal of the first voltage follower (U1) and the output terminal of the first voltage follower (U1) are connected in parallel to one end of an eighth resistor (R8), the other end of the eighth resistor (R8) is respectively connected to one end of a ninth resistor (R9) and the negative phase input terminal of a second comparator (U2), and the positive phase input terminal of the second comparator (U2) is grounded; the output terminal of the second comparator (U2) and the other end of the ninth resistor (R9) are connected in parallel to one end of a tenth resistor (R10), and the other end of the tenth resistor (R10) is respectively connected to the positive phase input terminal of a third comparator (U3) and the positive phase input terminal of a fifth comparator (U5).

[0014] Preferably, the second signal input unit comprises a sixth comparator (U6) and a fourth comparator (U4):

[0015] The second signal input terminal is connected to one end of the twenty-sixth resistor (R26), the other end of the twenty-sixth resistor (R26) is respectively connected to the positive electrode of the fourth diode (D4), one end of the twenty-fifth resistor (R25), one end of the second capacitor (C2), and the non-inverting input terminal of the sixth comparator (U6); the cathode of the fourth diode (D4) is connected to the fifth power supply, the other end of the twenty-fifth resistor (R25) is grounded, and the other end of the second capacitor (C2) is grounded;

[0016] The negative phase input terminal of the sixth comparator (U6) and the output terminal of the sixth comparator (U6) are connected in parallel to one end of the twenty-fourth resistor (R24), the other end of the twenty-fourth resistor (R24) is respectively connected to one end of the first capacitor (C1) and one end of the seventeenth resistor (R17), the other end of the seventeenth resistor (R17) and the control end are respectively connected in parallel to the collector of the first triode (Q1), the cathode of the second diode (D2), one end of the sixteenth resistor (R16), and the positive phase input terminal of the fourth comparator (U4); the anode of the second diode (D2) is grounded, the other end of the sixteenth resistor (R16) is grounded, and the other end of the first capacitor (C1) is grounded;

[0017] The negative phase input terminal of the fourth comparator (U4) and the output terminal of the fourth comparator (U4) are connected in parallel to one end of an eighteenth resistor (R18), and the other end of the eighteenth resistor (R18) is respectively connected to the positive phase input terminal of the third comparator (U3) and the positive phase input terminal of the fifth comparator (U5).

[0018] Preferably, the first switch unit includes a third transistor (Q3):

[0019] The emitter of the third transistor (Q3) is grounded, the base of the third transistor (Q3) is connected to one end of the fourth resistor (R4), the other end of the fourth resistor (R4) is respectively connected to one end of the third resistor (R3) and the collector of the second transistor (Q2), and the other end of the third resistor (R3) is connected to the first power supply.

[0020] Preferably, the second switch unit comprises a first transistor (Q1) and a second transistor (Q2):

[0021] The first determination point (M1) is connected to one end of the first resistor (R1) and one end of the second resistor (R2), respectively; the other end of the first resistor (R1) is connected to the base of the first transistor (Q1), and the emitter of the first transistor (Q1) is grounded; the other end of the second resistor (R2) is connected to the base of the second transistor (Q2), and the emitter of the second transistor (Q2) is grounded.

[0022] Preferably, the first voltage regulating unit comprises a fifth comparator (U5):

[0023] The negative phase input terminal of the fifth comparator (U5) is respectively connected to one end of the nineteenth resistor (R19) and one end of the twentieth resistor (R20); the other end of the nineteenth resistor (R19) is respectively connected to one end of the twenty-first resistor (R21) and one end of the twenty-second resistor (R22); the other end of the twenty-first resistor (R21) is grounded; the other end of the twenty-second resistor (R22) is grounded; the other end of the twentieth resistor (R20), the control end of the twentieth resistor (R20), and the output end of the fifth comparator (U5) are connected in parallel to one end of the twenty-third resistor (R23); the other end of the twenty-third resistor (R23) is connected to the eighth port (8) of the relay (U7).

[0024] Preferably, the second voltage regulating unit comprises a third comparator (U3):

[0025] The negative phase input terminal of the third comparator (U3) is respectively connected to one end of the eleventh resistor (R11) and one end of the twelfth resistor (R12); the other end of the eleventh resistor (R11) is respectively connected to one end of the thirteenth resistor (R13) and one end of the fourteenth resistor (R14); the other end of the thirteenth resistor (R13) is grounded; the other end of the fourteenth resistor (R14) is grounded; the other end of the twelfth resistor (R12), the control end of the twelfth resistor (R12), and the output end of the third comparator (U3) are connected in parallel to one end of the fifteenth resistor (R15); the other end of the fifteenth resistor (R15) is connected to the third port (3) of the relay (U7).

[0026] Preferably, the voltage display unit comprises a relay (U7):

[0027] The second port (2) and the sixth port (6) of the relay (U7) are connected in parallel to the output end;

[0028] The first port (1) of the relay (U7) is respectively connected to one end of the first inductor (L1), the positive electrode of the third diode (D3), and the collector of the fourth transistor (Q4); the other end of the first inductor (L1) is connected to the fifth port (5) of the relay (U7); the fifth port (5) of the relay (U7) and the negative electrode of the third diode (D3) are connected in parallel to the fourth power supply; the emitter of the fourth transistor (Q4) is grounded; the base of the fourth transistor (Q4) is connected to one end of the twenty-seventh resistor (R27), and the other end of the twenty-seventh resistor (R27) is connected to the second determination point (M2).

[0029] The utility model also provides a wire feeding machine, which comprises a voltage pre-display and real-display switching system.

[0030] In summary, due to the adoption of the above technical solution, compared with the prior art, the utility model has at least the following beneficial effects:

[0031] The utility model arranges a first switch unit and a second switch unit, and realizes the separate processing of the first signal and the second signal by controlling the on and off of the first switch unit and the second switch unit, thereby avoiding the simultaneous processing of the same line of the pre-display and the real display, realizing the classification of the welding machine input voltage and the pre-made voltage, and completing 1:1 display. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a schematic diagram of a voltage pre-display and real-display switching system according to an exemplary embodiment of the present invention.

[0033] Figure 2 The figure is a schematic diagram of a voltage pre-display and real-display switching system in a no-load state according to an exemplary embodiment of the present utility model.

[0034] Figure 3 The figure is a schematic diagram of a voltage pre-display and real-display switching system in a load state according to an exemplary embodiment of the present utility model. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the embodiments and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] like Figure 1 As shown, the utility model provides a voltage pre-display and real display switching system, including a first signal input unit, a first switch unit, a first voltage regulating unit, a second signal input unit, a second switch unit, a second voltage regulating unit, and a voltage display unit.

[0038] In this embodiment, the output end of the first signal input unit is respectively connected to the input end of the first switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit, the output end of the second signal input unit is respectively connected to the input end of the second switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit, the output end of the first voltage regulating unit and the output end of the second voltage regulating unit are connected in parallel to the input end of the voltage display unit; the output end of the first switch unit is grounded, and the output end of the second switch unit is grounded.

[0039] In this embodiment, the first signal input by the first signal input unit is a voltage pre-display given signal, and the second signal input by the second signal input unit is a welding machine input voltage.

[0040] In this embodiment, in the no-load state, the second switch unit is turned on, so the second signal (welding machine input voltage) input by the second signal input unit is grounded through the second switch unit and will not affect the voltage display; at the same time, the first switch unit is turned off, so the first signal (voltage pre-display given signal) input by the first signal input unit will not be cut off in the first switch unit, and since the first voltage regulating unit is turned on and the second voltage regulating unit is turned off, the first signal (voltage pre-display given signal) is pre-displayed in the voltage display unit after passing through the first voltage regulating unit.

[0041] In this embodiment, in the load state, the first switch unit is turned on, so the first signal (voltage pre-display given signal) input by the first signal input unit is grounded through the first switch unit and will not affect the voltage display; at the same time, the second switch unit is turned off, so the second signal (welding machine input voltage) input by the second signal input unit will not be cut off in the second switch unit, and since the second voltage regulating unit is turned on and the first voltage regulating unit is turned off, the second signal (welding machine input voltage) is displayed in the voltage display unit after passing through the second voltage regulating unit.

[0042] like Figure 2 As shown, the first signal input unit includes a first voltage follower U1 and a second comparator U2:

[0043] The first signal input terminal (IN1, voltage pre-display given signal) is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to one end of the sixth resistor R6 (adjustable resistor) and the control terminal, the other end of the sixth resistor R6 is respectively connected to the cathode of the first diode D1, one end of the fifth resistor R5, the collector of the third transistor Q3, and the positive phase input terminal of the first voltage follower U1; the anode of the first diode D1 is grounded, and the other end of the fifth resistor R5 is grounded;

[0044] The negative phase input terminal of the first voltage follower U1 and the output terminal of the first voltage follower U1 are connected in parallel to one end of the eighth resistor R8, the other end of the eighth resistor R8 is respectively connected to one end of the ninth resistor R9 and the negative phase input terminal of the second comparator U2, and the positive phase input terminal of the second comparator U2 is grounded; the output terminal of the second comparator U2 and the other end of the ninth resistor R9 are connected in parallel to one end of the tenth resistor R10, the other end of the tenth resistor R10 and the first signal output terminal (OUT1, providing a voltage signal for the device voltage display) are connected in parallel to the positive phase input terminal of the third comparator U3 and the positive phase input terminal of the fifth comparator U5.

[0045] In this embodiment, when the third transistor Q3 is turned off, the first signal inputted from the first signal input terminal is transmitted through R7, R6 (pre-adjustment) and the first voltage follower U1. At the same time, U1 also plays an isolation role. Due to the high impedance of the operational amplifier, the input signal can follow the output, and the output signal cannot interfere with the input terminal. U1 outputs to the inverting input terminal of U2. Here, R8=R9 is selected to make U2 a voltage inverter, which outputs a negative voltage signal after reversing the voltage amplitude. When the third transistor Q3 is turned on, the first signal is grounded through Q3 and will not interfere with the voltage display.

[0046] like Figure 2 As shown, the second signal input unit includes a sixth comparator U6 and a fourth comparator U4:

[0047] The second signal input terminal (IN2, welding machine input voltage) is connected to one end of the twenty-sixth resistor R26, and the other end of the twenty-sixth resistor R26 is respectively connected to the anode of the fourth diode D4, one end of the twenty-fifth resistor R25, one end of the second capacitor C2, and the non-inverting input terminal of the sixth comparator U6; the cathode of the fourth diode D4 is connected to the fifth power supply VCC5, the other end of the twenty-fifth resistor R25 is grounded, and the other end of the second capacitor C2 is grounded;

[0048] The negative phase input terminal of the sixth comparator U6 and the output terminal of the sixth comparator U6 are connected in parallel to one end of the twenty-fourth resistor R24, the other end of the twenty-fourth resistor R24 ​​is respectively connected to one end of the first capacitor C1 and one end of the seventeenth resistor R17 (adjustable resistor), the other end and the control end of the seventeenth resistor R17 are respectively connected in parallel to the collector of the first transistor Q1, the cathode of the second diode D2, one end of the sixteenth resistor R16, and the positive phase input terminal of the fourth comparator U4; the anode of the second diode D2 is grounded, the other end of the sixteenth resistor R16 is grounded, and the other end of the first capacitor C1 is grounded;

[0049] The negative phase input terminal of the fourth comparator U4 and the output terminal of the fourth comparator U4 are connected in parallel to one end of the eighteenth resistor R18, and the other end of the eighteenth resistor R18 is respectively connected to the positive phase input terminal of the third comparator U3 and the positive phase input terminal of the fifth comparator U5.

[0050] In this embodiment, when the first transistor Q1 is turned off, the second signal inputted from the second signal input terminal (IN2) is processed by R26, R25 (voltage divider), U6 (filtering), and U4, and then the voltage signal is outputted to U3; when the first transistor Q1 is turned on, the second signal is grounded through Q1, and will not interfere with the voltage pre-display.

[0051] The utility model avoids processing the same circuit of the pre-display and the real display at the same time, realizes the classification of the welding machine input voltage and the pre-made voltage, and completes the 1:1 display.

[0052] For example, welding machines are classified into two categories, one is the CC mode constant current mode arc welding machine, and the other is the CV mode constant voltage mode gas shielded welding machine. In CC mode, the equipment is adjusted to the current pre-adjustment, for example, adjusting -200A, the welding current is about 200A when welding; but for CV gas shielded welding machine, the pre-adjustment voltage is set, for example, setting -20V, then the welding voltage is about 20V when welding. The more accurate the pre-adjustment is to the actual reality, the easier it is for users to use. The voltage can be adjusted according to different welding requirements. If the deviation between the pre-adjustment and the actual output is too large, users are more required to match the actual machine on site to find the right feel, which is extremely unfriendly to the user experience.

[0053] like Figure 2 As shown, the first switch unit includes a third transistor Q3:

[0054] The emitter of the third transistor Q3 is grounded, the base of the third transistor Q3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is respectively connected to one end of the third resistor R3 and the collector of the second transistor Q2, and the other end of the third resistor R3 is connected to the first power supply VCC1.

[0055] like Figure 2 As shown, the second switch unit includes a first transistor Q1 and a second transistor Q2:

[0056] The first determination point M1 is connected to one end of the first resistor R1 and one end of the second resistor R2 respectively. The other end of the first resistor R1 is connected to the base of the first transistor Q1, and the emitter of the first transistor Q1 is grounded; the other end of the second resistor R2 is connected to the base of the second transistor Q2, and the emitter of the second transistor Q2 is grounded.

[0057] When no-load, the first judgment point M1 is at a high level, Q1 and Q2 are turned on, the base voltage of Q3 is 0, Q3 is turned off, that is, the second switch unit is turned on, and the first switch unit is turned off; when loaded, the first judgment point M1 is at a low level, Q1 and Q2 are turned off, the base of Q3 is at a high level, Q3 is turned on, that is, the second switch unit is turned off, and the first switch unit is turned on.

[0058] like Figure 2 As shown, the first voltage regulating unit includes a fifth comparator U5:

[0059] The negative phase input terminal of the fifth comparator U5 is respectively connected to one end of the nineteenth resistor R19 and one end of the twentieth resistor R20 (adjustable resistor), the other end of the nineteenth resistor R19 is respectively connected to one end of the twenty-first resistor R21 and one end of the twenty-second resistor R22, the other end of the twenty-first resistor R21 is grounded, and the other end of the twenty-second resistor R22 is grounded; the other end of the twentieth resistor R20, the control end of the twentieth resistor R20, and the output end of the fifth comparator U5 are connected in parallel to one end of the twenty-third resistor R23, and the other end of the twenty-third resistor R23 is connected to the eighth port 8 of the relay U7.

[0060] In this embodiment, the first signal (voltage pre-display given signal) input by the first signal input unit can be adjusted by the twentieth resistor R20.

[0061] like Figure 2 As shown, the second voltage regulating unit includes a third comparator U3:

[0062] The negative phase input terminal of the third comparator U3 is respectively connected to one end of the eleventh resistor R11 and one end of the twelfth resistor R12 (adjustable resistor), the other end of the eleventh resistor R11 is respectively connected to one end of the thirteenth resistor R13 and one end of the fourteenth resistor R14, the other end of the thirteenth resistor R13 is grounded, and the other end of the fourteenth resistor R14 is grounded; the other end of the twelfth resistor R12, the control end of the twelfth resistor R12, and the output end of the third comparator U3 are connected in parallel to one end of the fifteenth resistor R15, and the other end of the fifteenth resistor R15 is connected to the third port 3 of the relay U7.

[0063] In this embodiment, the second signal (welding machine input voltage) input by the second signal input unit can be adjusted by the twelfth resistor R12.

[0064] like Figure 2 , Figure 3 As shown, the voltage display unit includes relay U7:

[0065] The second port 2 and the sixth port 6 of the relay U7 are connected in parallel to the output terminal (OUT), wherein the second port 2 and the sixth port 6 are single-pole double-throw switches respectively; the sixth port 6 can be connected to the eighth port 8 and the seventh port 7 respectively, and the second port 2 can be connected to the fourth port 4 and the third port 3 respectively;

[0066] The first port 1 of the relay U7 is respectively connected to one end of the first inductor L1, the anode of the third diode D3, and the collector of the fourth transistor Q4; the other end of the first inductor L1 is connected to the fifth port 5 of the relay U7; the fifth port 5 of the relay U7 and the cathode of the third diode D3 are connected in parallel to the fourth power supply VCC4; the emitter of the fourth transistor Q4 is grounded; the base of the fourth transistor Q4 is connected to one end of the twenty-seventh resistor R27; the other end of the twenty-seventh resistor R27 is connected to the second determination point M2.

[0067] In this embodiment, Figure 2 As shown, when no-load, the first determination point M1 is at a high level, Q1 and Q2 are turned on, the base voltage of Q3 is 0, Q3 is turned off, that is, the second switch unit is turned on, the first switch unit is turned off, and the second signal is grounded through the second switch unit; the second determination point M2 is at a high level, Q4 is turned on, the sixth port 6 and the eighth port 8 are connected, the second port 2 and the fourth port 4 are connected, that is, the first voltage regulating unit is turned on, and the second voltage regulating unit is turned off, therefore, the first signal is transmitted to the output end after passing through the first signal input unit and the first voltage regulating unit.

[0068] In this embodiment, Figure 3 As shown, when the load is on, the first determination point M1 is at a low level, Q1 and Q2 are turned off, the base of Q3 is at a high level, Q3 is turned on, that is, the second switch unit is turned off, the first switch unit is turned on, and the first signal is grounded through the first switch unit; at the same time, the second determination point M2 is at a low level, Q4 is not turned on, the sixth port 6 and the seventh port 7 are connected, the second port 2 and the third port 3 are connected, that is, the first voltage regulating unit is turned off, and the second voltage regulating unit is turned on, therefore, the second signal is transmitted to the output end after passing through the second signal input unit and the second voltage regulating unit.

[0069] In this embodiment, the M1 and M2 judgment points are the same signal point, which is the high and low level output signal point in the external control circuit. The peripheral control circuit ensures that a high level 12V is output when no-load. At this time, Q1 is turned on, and the interference signal of the IN2 welding voltage feedback part cannot be transmitted to the back end through U4. Q2 is turned on, Q3 is cut off, and the pre-adjustment signal is successfully transmitted to the back-end control and signal output through U1. At the same time, since M2 is also a high level signal, Q4 is turned on and the relay contacts are changed, so the pre-adjustment signal is inverted by U2 and output to the voltage display table of the equipment, and U5 is output to the voltage display of the wire feeder through the relay after voltage adjustment.

[0070] In this embodiment, in the two in-phase proportional amplifier circuits U5 and U3, feedback control is added to the inverting input terminal to improve the stability of the amplifier and reduce nonlinear distortion. By connecting a positive voltage signal to the inverting input terminal, feedback control can be conveniently performed to adjust the gain and response characteristics of the amplifier.

[0071] The utility model also provides a wire feeding machine, which comprises a voltage pre-display and real-display switching system.

[0072] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A voltage pre-display and real-display switching system, characterized in that , including a first switch unit, a second switch unit, a first voltage regulating unit and a second voltage regulating unit; and also including a first signal input unit and a second signal input unit; The output end of the first signal input unit is connected to the input end of the first switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit respectively; the output end of the second signal input unit is connected to the input end of the second switch unit, the input end of the first voltage regulating unit, and the input end of the second voltage regulating unit respectively; the output end of the first voltage regulating unit and the output end of the second voltage regulating unit are connected in parallel to the input end of the voltage display unit; the output end of the first switch unit is grounded, and the output end of the second switch unit is grounded; When no-load, the second switch unit and the first voltage regulating unit are turned on, the first switch unit and the second voltage regulating unit are turned off, and the input first signal is displayed after passing through the first voltage regulating unit; When the load is on, the second switch unit and the first voltage regulating unit are turned off, the first switch unit and the second voltage regulating unit are turned on, and the input second signal is displayed after passing through the second voltage regulating unit.

2. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the first signal input unit includes a first voltage follower (U1) and a second comparator (U2): The first signal input terminal is connected to one end of the seventh resistor (R7), the other end of the seventh resistor (R7) is connected to one end of the sixth resistor (R6) and the control terminal, the other end of the sixth resistor (R6) is respectively connected to the cathode of the first diode (D1), one end of the fifth resistor (R5), the collector of the third transistor (Q3), and the non-phase input terminal of the first voltage follower (U1); the anode of the first diode (D1) is grounded, and the other end of the fifth resistor (R5) is grounded; The negative phase input terminal of the first voltage follower (U1) and the output terminal of the first voltage follower (U1) are connected in parallel to one end of an eighth resistor (R8), the other end of the eighth resistor (R8) is respectively connected to one end of a ninth resistor (R9) and the negative phase input terminal of a second comparator (U2), and the positive phase input terminal of the second comparator (U2) is grounded; the output terminal of the second comparator (U2) and the other end of the ninth resistor (R9) are connected in parallel to one end of a tenth resistor (R10), and the other end of the tenth resistor (R10) is respectively connected to the positive phase input terminal of a third comparator (U3) and the positive phase input terminal of a fifth comparator (U5).

3. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the second signal input unit includes a sixth comparator (U6) and a fourth comparator (U4): The second signal input terminal is connected to one end of the twenty-sixth resistor (R26), the other end of the twenty-sixth resistor (R26) is respectively connected to the positive electrode of the fourth diode (D4), one end of the twenty-fifth resistor (R25), one end of the second capacitor (C2), and the non-inverting input terminal of the sixth comparator (U6); the cathode of the fourth diode (D4) is connected to the fifth power supply, the other end of the twenty-fifth resistor (R25) is grounded, and the other end of the second capacitor (C2) is grounded; The negative phase input terminal of the sixth comparator (U6) and the output terminal of the sixth comparator (U6) are connected in parallel to one end of the twenty-fourth resistor (R24), the other end of the twenty-fourth resistor (R24) is respectively connected to one end of the first capacitor (C1) and one end of the seventeenth resistor (R17), the other end of the seventeenth resistor (R17) and the control end are respectively connected in parallel to the collector of the first triode (Q1), the cathode of the second diode (D2), one end of the sixteenth resistor (R16), and the positive phase input terminal of the fourth comparator (U4); the anode of the second diode (D2) is grounded, the other end of the sixteenth resistor (R16) is grounded, and the other end of the first capacitor (C1) is grounded; The negative phase input terminal of the fourth comparator (U4) and the output terminal of the fourth comparator (U4) are connected in parallel to one end of an eighteenth resistor (R18), and the other end of the eighteenth resistor (R18) is respectively connected to the positive phase input terminal of the third comparator (U3) and the positive phase input terminal of the fifth comparator (U5).

4. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the first switch unit includes a third transistor (Q3): The emitter of the third transistor (Q3) is grounded, the base of the third transistor (Q3) is connected to one end of the fourth resistor (R4), the other end of the fourth resistor (R4) is respectively connected to one end of the third resistor (R3) and the collector of the second transistor (Q2), and the other end of the third resistor (R3) is connected to the first power supply.

5. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the second switch unit includes a first transistor (Q1) and a second transistor (Q2): The first determination point (M1) is connected to one end of the first resistor (R1) and one end of the second resistor (R2), respectively; the other end of the first resistor (R1) is connected to the base of the first transistor (Q1), and the emitter of the first transistor (Q1) is grounded; the other end of the second resistor (R2) is connected to the base of the second transistor (Q2), and the emitter of the second transistor (Q2) is grounded.

6. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the first voltage regulating unit includes a fifth comparator (U5): The negative phase input terminal of the fifth comparator (U5) is respectively connected to one end of the nineteenth resistor (R19) and one end of the twentieth resistor (R20); the other end of the nineteenth resistor (R19) is respectively connected to one end of the twenty-first resistor (R21) and one end of the twenty-second resistor (R22); the other end of the twenty-first resistor (R21) is grounded; the other end of the twenty-second resistor (R22) is grounded; the other end of the twentieth resistor (R20), the control end of the twentieth resistor (R20), and the output end of the fifth comparator (U5) are connected in parallel to one end of the twenty-third resistor (R23); the other end of the twenty-third resistor (R23) is connected to the eighth port (8) of the relay (U7).

7. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the second voltage regulating unit includes a third comparator (U3): The negative phase input terminal of the third comparator (U3) is respectively connected to one end of the eleventh resistor (R11) and one end of the twelfth resistor (R12); the other end of the eleventh resistor (R11) is respectively connected to one end of the thirteenth resistor (R13) and one end of the fourteenth resistor (R14); the other end of the thirteenth resistor (R13) is grounded; the other end of the fourteenth resistor (R14) is grounded; the other end of the twelfth resistor (R12), the control end of the twelfth resistor (R12), and the output end of the third comparator (U3) are connected in parallel to one end of the fifteenth resistor (R15); the other end of the fifteenth resistor (R15) is connected to the third port (3) of the relay (U7).

8. A voltage pre-display and real-display switching system as claimed in claim 1, characterized in that , the voltage display unit includes a relay (U7): The second port (2) and the sixth port (6) of the relay (U7) are connected in parallel to the output end; The first port (1) of the relay (U7) is respectively connected to one end of the first inductor (L1), the positive electrode of the third diode (D3), and the collector of the fourth transistor (Q4); the other end of the first inductor (L1) is connected to the fifth port (5) of the relay (U7); the fifth port (5) of the relay (U7) and the negative electrode of the third diode (D3) are connected in parallel to the fourth power supply; the emitter of the fourth transistor (Q4) is grounded; the base of the fourth transistor (Q4) is connected to one end of the twenty-seventh resistor (R27), and the other end of the twenty-seventh resistor (R27) is connected to the second determination point (M2).

9. A wire feeder, characterized in that: It comprises a voltage pre-display and real-display switching system as described in any one of claims 1 to 8.

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