Multifunctional preset current and voltage sampling circuit suitable for gas shield welding power supply

Abstract

The utility model provides a multifunctional preset current and voltage sampling circuit suitable for a gas shield welding power supply, an acquisition state switching unit of the multifunctional preset current and voltage sampling circuit is configured to output at least one path of acquisition switching signal, and each acquisition switching signal has two acquisition states to respectively correspond to preset current acquisition and preset voltage acquisition on a wire feeder. The preset signal source lead-in unit comprises an analog quantity interface and two lead-in channels connected in parallel, the two lead-in channels are correspondingly connected with a preset current source and a preset voltage source respectively, and each lead-in channel is provided with a conduction element connected to the output end of the acquisition state switching unit; and based on the control of two acquisition states in the acquisition switching signal, only one lead-in path is conducted at any moment so as to lead in a preset current signal or a preset voltage signal. And the bidirectional amplitude conversion unit comprises at least one phase inverter so as to convert the signal imported by the preset signal source import unit into a forward analog quantity signal and output the forward analog quantity signal to a sampling interface of the welding power supply control module.

Description

Technical Field

[0001] The utility model relates to the technical field of welding, and in particular to a multifunctional preset current and voltage sampling circuit suitable for a gas shielded welding power source. Background Art

[0002] Gas shielded welding refers to a welding method that uses carbon dioxide or argon gas for protection. In existing gas shielded welding, the adjustment of preset current and preset voltage is achieved based on the adjustment of two potentiometers on the wire feeder. When the welding power supply collects the preset current and preset voltage signals, it is necessary to lead the preset current and preset voltage signals from the wire feeder respectively, and then connect the two analog signals to their respective signal conditioning circuits through a square wave generator and an electronic switch for filtering and analog signal isolation and conversion, and finally connect them to the two ADC channel interfaces of the welding power supply core DSP (or MCU) for signal acquisition.

[0003] This signal source acquisition method has the following disadvantages: 1. After the preset signal source is introduced, an additional square wave generator circuit needs to be added, which increases the cost; 2. The two introduced signal sources need to be conditioned separately, which not only involves a large number of repeated conditioning circuit components and occupies a large area, but also leads to further increase in costs; 3. The welding power supply core DSP (or MCU) needs to allocate two channel ADC sampling interfaces, which not only occupies more special peripheral interface resources, but also requires more ADC sampling time of the core DSP (or MCU); 4. The preset current and preset voltage signal import interfaces are fixed, with poor flexibility and are not conducive to the digital upgrade and expansion of the welding power supply. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the utility model provides a multifunctional preset current and voltage sampling circuit which integrates the introduction of preset current and preset voltage and has a flexible and changeable introduction interface and is suitable for a gas shielded welding power source.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply, which includes a collection state switching unit, a preset signal source importing unit and a bidirectional amplitude conversion unit. The collection state switching unit is configured to output at least one collection switching signal, and each collection switching signal has two collection states to correspond to the preset current collection and preset voltage collection on the wire feeder respectively. The preset signal source importing unit includes an analog interface and two parallel importing paths, the two importing paths correspond to the preset current source and preset voltage source on the wire feeder respectively, and each importing path has a conducting element connected to the output end of the collection state switching unit; based on the control of the two collection states in the collection switching signal, only one importing path is turned on at any time to import the preset current signal or preset voltage signal on the wire feeder. The bidirectional amplitude conversion unit includes at least one inverter to convert the preset current signal or preset voltage signal imported by the preset signal source importing unit into a positive analog signal and output it to the sampling interface of the welding power supply control module.

[0006] According to one embodiment of the utility model, the analog interface includes a single analog interface and / or a dual analog interface; the single analog interface and the dual analog interface are respectively connected to a preset current source and a preset voltage source on the wire feeder through two parallel import paths.

[0007] According to one embodiment of the utility model, the analog quantity interface includes a single analog quantity interface and a dual analog quantity interface, and the acquisition state switching unit outputs two acquisition switching signals to respectively control the conducting elements on the two parallel import paths corresponding to the two interfaces; the multifunctional preset current and voltage sampling circuit suitable for the gas shielded welding power supply also includes an interface switching switch unit, one side of the interface switching switch unit is alternately connected to the two import paths of the single analog quantity interface and the dual analog quantity interface, and the other side thereof is connected to the bidirectional amplitude conversion unit.

[0008] According to one embodiment of the utility model, the outer side of the single analog interface is respectively connected to a preset current source and a preset voltage source on the wire feeder via two diodes with opposite conduction directions to form two parallel import paths, and the inner side of the interface is directly connected to the output end of the acquisition state switching unit.

[0009] According to one embodiment of the utility model, the outer side of the interface of the dual analog interface is directly connected to the preset current source and the preset voltage source on the wire feeder, the two import paths are located on the inner side of the interface of the dual analog interface and both include an RC voltage divider filter network and a switch tube that connects the RC voltage divider filter network to the ground potential, the conduction conditions of the switch tubes on the two import paths are opposite, and the output ends of the RC voltage divider filter network of the two import paths are both connected to the follower, and are connected to the bidirectional amplitude conversion unit after being followed by the follower.

[0010] According to an embodiment of the present invention, the interface switching unit is one or more toggle switches; or one or more analog switches; or a multi-way switch circuit constructed by triodes.

[0011] According to one embodiment of the utility model, the preset signal source import unit includes a signal transmission element and a comparator whose output amplitude is greater than the maximum adjustment amplitude of the two analog signal sources. The input end of the signal transmission element is connected to the IO port of the welding power supply control module. Based on the pulse signal output by the IO port, the signal transmission element outputs a first acquisition switching signal opposite to the pulse signal state to control the conduction elements on the two import paths of the dual analog interface; the first acquisition switching signal is connected to the comparator, and after comparison with the reference signal of the comparator, the second acquisition switching signal is output to control the conduction elements on the two import paths on the single analog interface.

[0012] According to an embodiment of the present invention, the signal transmission element is an optocoupler isolation element; or a triode or a MOS tube.

[0013] According to one embodiment of the utility model, the bidirectional amplitude conversion unit includes a signal follower, a first inverter and a second inverter connected in series in sequence, the signal follower follows the preset current signal or the preset voltage signal introduced by the preset signal source introduction unit to the inverting end of the first inverter, the positive end of the first inverter is grounded, the output end of the first inverter is connected to the reverse end of the second inverter, a reverse blocking diode and at least one first reverse proportional resistor are connected between the reverse end and the output end of the first inverter, the output of the first inverter is connected to the inverting end of the second inverter, the positive end of the second inverter is grounded, at least one second reverse proportional resistor is connected between the output end and the reverse end of the second inverter, and the output of the second inverter is connected to the sampling interface of the welding power supply control module.

[0014] According to one embodiment of the utility model, a multifunctional preset current and voltage sampling circuit suitable for a gas shielded welding power supply also includes an analog isolation unit composed of a linear optocoupler, and the analog isolation unit is connected between the bidirectional amplitude conversion unit and the sampling interface of the welding power supply control module.

[0015] In summary, the utility model realizes the import of preset current signals and preset voltage signals on the wire feeder based on the acquisition switching signal output by the acquisition state switching unit and the two-way import path provided by the preset signal source import unit, and at the same time, the imported analog signals can be conditioned by the bidirectional amplitude conversion unit, so that only one sampling interface on the welding power supply control module is needed to complete the collection of all data during sampling. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply provided by the utility model realizes the integrated import of two-way analog signals, which not only greatly simplifies the circuit structure and reduces the cost, but also effectively reduces the use of limited external interfaces on the welding control module, saving interface resources. In addition, based on the setting of the single analog interface and the dual analog interface in the preset signal source import unit, the preset current source and preset voltage source on the wire feeder can be imported in the form of one analog signal or two analog signals, which greatly improves the flexibility of signal source import.

[0016] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure shows a principle block diagram of a multifunctional preset current and voltage sampling circuit suitable for a gas shielded welding power supply provided by an embodiment of the utility model.

[0018] Figure 2 Shown Figure 1 The circuit schematic diagram of the acquisition state switching unit, the preset signal source import unit and the interface switching switch unit.

[0019] Figure 3 Shown is the circuit schematic diagram of the bidirectional amplitude conversion unit and the analog isolation unit.

[0020] Figure 4 Shown Figure 1 Interface diagram of the welding power supply control module.

[0021] Figure 5 Shown Figure 1 The timing diagram of each signal node when a single analog interface is used to import two external analog signal sources.

[0022] Figure 6 Shown Figure 1 The timing diagram of each signal node when a dual analog interface is used to import two external analog signal sources. DETAILED DESCRIPTION

[0023] like Figures 1 to 6As shown, the multifunctional preset current and voltage sampling circuit (also referred to as the multifunctional preset current and voltage sampling circuit) for gas shielded welding power source provided in this embodiment includes a collection state switching unit 10, a preset signal source importing unit 20, and a bidirectional amplitude conversion unit 40. The collection state switching unit 10 is configured to output at least one collection switching signal, and each collection switching signal has two collection states to respectively correspond to the preset current collection and preset voltage collection on the wire feeder. The preset signal source importing unit 20 includes an analog interface and two parallel importing paths, the two importing paths respectively correspond to the preset current source and the preset voltage source connected to the wire feeder, and each importing path has a conducting element connected to the output end of the collection state switching unit; based on the control of the two collection states in the collection switching signal, only one importing path is turned on at any time to import the preset current signal or preset voltage signal on the wire feeder. The bidirectional amplitude conversion unit 40 includes at least one inverter to convert the preset current signal or the preset voltage signal introduced by the preset signal source introduction unit 20 into a positive analog signal and output it to the sampling interface of the welding power supply control module 60 .

[0024] like Figure 2 As shown, in this embodiment, the analog interface includes a single analog interface J1 and a dual analog interface J2, the single analog interface J1 is connected to the preset current source S2 and the preset voltage source S1 on the wire feeder through two parallel import paths, and the dual analog interface J2 is connected to the preset current source S2 and the preset voltage source S1 on the wire feeder through another two parallel import paths. The acquisition state switching unit 10 outputs two acquisition switching signals to respectively control the conductive elements on the two parallel import paths corresponding to the two interfaces. The multifunctional preset current and voltage sampling circuit also includes an interface switching switch unit 30, one side of the interface switching switch unit 30 is alternately connected to the two import paths of the single analog interface J1 and the dual analog interface J2, and the other side thereof is connected to the bidirectional amplitude conversion unit 40. This setting makes it possible for the multifunctional preset current and voltage sampling circuit provided in this embodiment to import the preset current source and preset current on the wire feeder through the single analog interface J1 in the form of one interface, and also to import the preset current source and preset current through the dual analog interface J2 in the form of two interfaces. The signal source import method is diversified, thereby greatly improving the flexibility of the sampling circuit application.

[0025] like Figure 2As shown, the outer side of the single interface of the single analog interface J1 is connected to the preset voltage source S1 and the preset current source S2 on the wire feeder through two diodes D1 and D2 with opposite conduction directions to form two parallel introduction paths, and the inner side of the single interface is directly connected to the output end of the acquisition state switching unit 10. The outer side of the dual interface of the dual analog interface J2 is directly connected to the preset voltage source S1 and the preset current source S2 on the wire feeder. The two introduction paths are located on the inner side of the dual interface of the dual analog interface J2 and both include RC voltage divider filter networks 201, 202 and switch tubes Q1, Q2 that connect the RC voltage divider filter networks 201, 202 to the ground potential respectively. The conduction conditions of the switch tubes Q1, Q2 are opposite. The output ends of the RC voltage divider filter networks 201, 202 of the two introduction paths are both connected to the follower U31B, and are connected to the bidirectional amplitude conversion unit 40 after the follower U31B. The preset voltage source S1 and the preset current source S2 on the wire feeder are both variable potentiometers connected between the +15V power supply and the ground potential GNDC, namely the preset voltage potentiometer VR1 and the preset current potentiometer VR2.

[0026] The preset signal source import unit 10 includes a signal transmission element U14 and a comparator U31A, and the output amplitude of the comparator U31A is greater than or equal to the maximum adjustment amplitude of the preset voltage source S1 and the preset current source S2. The input end of the signal transmission element U14 is connected to the IO port of the welding power supply control module 60. Based on the pulse signal DSP_UI_SWITCH output by the IO port, the signal transmission element U14 outputs the first acquisition switching signal UI_SWITCH opposite to the pulse signal DSP_UI_SWITCH state to control the conductive elements on the two import paths of the dual analog interface J2, namely, the switch tubes Q1 and Q2. The first acquisition switching signal UI_SWITCH is connected to the comparator U31A, and after being compared with the reference signal of the comparator U31A, the second acquisition switching signal (i.e., the output amplitude of the comparator U31A +15V and -15V) is output to control the conductive elements on the two import paths on the single analog interface J1, namely, the diodes D1 and D2.

[0027] In the present embodiment, the welding power supply control module 60 is a DSP module, and the input signal of the acquisition state switching unit 10 is a pulse signal of a fixed frequency and a duty cycle generated by the DSP module IO port. The signal is defined as a preset current acquisition state when it is at a low level, and as a preset voltage acquisition state when it is at a high level. However, the present invention does not make any limitation to this. In other embodiments, the welding power supply control module may also be an MCU module. In the present embodiment, the signal transmission element U14 is an optocoupler isolation element, which realizes signal isolation from the DSP module IO port to the acquisition state switching unit 10 while realizing signal transmission, thereby avoiding interference of the analog acquisition signal on the welding control module 60. However, the present invention does not make any limitation to this. In other embodiments, when signal isolation is not required, a triode or MOS tube may also be used for signal transmission.

[0028] like Figure 2 As shown, when using the single analog interface J1: if the first acquisition switching signal UI_SWITCH is at a low level, the +pin voltage of the comparator U31A is lower than the -pin voltage of the comparator U31A (the voltage divided on the resistor R61), and the 1-pin of the comparator U31A outputs a -15V amplitude voltage to form the second acquisition switching signal. At this time, the diode D1 on the external connection side of the single analog interface J1 is turned on, so that the preset voltage signal on the preset voltage potentiometer VR1 is introduced into the single analog signal source introduction node TP3 through the single analog interface J1. If the UI_SWITCH signal is at a high level, the +pin voltage of the comparator U31A (the +15V voltage connected to the resistor R9) is higher than the -pin voltage (the voltage divided on the resistor R61), so that the 1-pin of the comparator U31A outputs a +15V voltage to form the second acquisition switching signal. At this time, the diode D2 on the external connection side of the single analog quantity interface J1 is turned on, so that the preset current signal on the preset current potentiometer VR2 is introduced into the single analog quantity signal source introduction node TP3 through the single analog quantity interface J1. The single analog quantity signal source introduction node TP3 is directly connected to the resistor R11 on the acquisition state switching unit 10 and forms a loop with the 1st pin of the comparator U31A. When the 1st pin of the comparator U31A outputs the second acquisition switching signal of +15V and -15V respectively, the single analog quantity signal source introduction node TP3 forms a positive amplitude voltage and a negative amplitude voltage to correspond to the preset current and preset voltage signals.

[0029] When the dual analog interface J2 is used, the external connection sides of pins 1 and 3 on the dual analog interface J2 are respectively connected to the signal output pins of the preset current potentiometer VR2 and the preset voltage potentiometer VR1, and the internal connection sides of pins 1 and 3 are respectively connected to the two parallel import paths. The preset voltage signal imported from pin 3 on the dual analog interface J2 is respectively connected to the drain of the N-type switch tube Q1 and the follower U31B after passing through the RC voltage divider filter network 201 composed of resistor R64, resistor R65 and capacitor C11, and the control electrode of the N-type switch tube Q1 is connected to the first acquisition switching signal, and its source is grounded. Similarly, the preset current signal imported from pin 1 on the dual analog interface J2 is respectively connected to the source of the P-type switch tube Q2 and the follower U31B after passing through the voltage divider filter network 202 composed of resistor R67, resistor R68 and capacitor C12, and the control electrode of the P-type switch tube Q2 is connected to the first acquisition switching signal, and its drain is grounded. When the first acquisition switching signal UI_SWITCH is at a high level, the N-type switch tube Q1 is triggered to turn on, and the preset voltage signal introduced at pin 3 on the dual analog interface J2 is directly connected to the ground potential GNDC by the N-type switch tube Q1, and it can no longer be output to the follower U31B and becomes invalid. On the contrary, at this time, the P-type switch tube Q2 is cut off, and the preset current signal introduced at pin 1 is output to the follower U31B for signal following and then output to the dual analog signal source import node TP4. Similarly, when the first acquisition switching signal UI_SWITCH is at a low level, the P-type switch tube Q2 is turned on and the preset current signal introduced at pin 1 becomes invalid, while the preset voltage signal introduced at pin 3 is output to the dual analog signal source import node TP4 after signal following by the follower U31B. That is, the control based on the first acquisition switching signal UI_SWITCH realizes the import of the preset current signal or preset voltage signal through the dual analog interface J2.

[0030] Although this embodiment is described by taking the preset signal source import unit 20 including a single analog interface J1 and a dual analog interface J2 as an example. However, the present invention does not impose any limitation on this. In other embodiments, the preset signal source import unit may also have only a single analog interface J1. Or only have a dual analog interface J2. In this case, there is no need to set a comparator U31A in the acquisition state switching unit to realize the generation of the second acquisition switching signal of -15V and -15V, that is, the acquisition state switching unit only needs to generate the first acquisition switching signal UI_SWITCH to perform the switching control of the two import paths on the dual analog interface J2.

[0031] like Figure 2As shown, the single analog signal source import node TP3 and the dual analog signal source import node TP4 are respectively connected to the input side of the interface switching switch unit 30, and the use of the single analog interface J1 or the dual analog interface J2 is realized based on the selection of the interface switching switch unit 30. In this embodiment, the interface switching switch unit 30 is a toggle switch, and its pins 2 and 5 are connected to the bidirectional amplitude conversion unit 40, which is responsible for transmitting the imported preset current signal or preset voltage signal to the bidirectional amplitude conversion unit 40. Pins 1 and 6 of the interface switching switch unit 30 are connected to the single analog signal source import node TP3, which is responsible for transmitting the signal imported by the single analog interface J1 to pins 2 and 5 of the interface switching switch unit 30; pins 3 and 4 of the interface switching switch unit 30 are connected to the dual analog signal source import node TP4, which is responsible for transmitting the signal imported by the dual analog interface J2 to pins 2 and 5 of the interface switching switch unit 30. However, the present invention does not impose any limitation on this. In other embodiments, the interface switching unit may also be a plurality of toggle switches; or one or more analog switches; or a multi-way switch circuit constructed by transistors.

[0032] After the preset current or voltage signal is introduced, the bidirectional amplitude conversion unit 40 is used for conditioning to convert the introduced signal into a positive signal. In this embodiment, the bidirectional amplitude conversion unit 40 includes a signal follower U13B, a first inverter U13D, a second inverter U13A connected in series, and an RC low-pass filter including a resistor R16 and a capacitor C5 connected to the output side of the second inverter U13. The signal follower U13B follows the preset current signal or the preset voltage signal introduced by the preset signal source introduction unit 20 to the inverting end of the first inverter U13D through the resistor R10. The positive end of the first inverter U13D is grounded. The output end of the first inverter U13D is connected to the inverting end of the second inverter U13A through the reverse blocking diode D7 and the resistor R14. The reverse blocking diode D5 and the first reverse proportional resistor R5 are connected in parallel between the inverting end and the output end of the first inverter U13D. The first reverse proportional resistor R4 is connected between the input side of the resistor R10 and the output side of the resistor R14. The output of the first inverter U13D is connected to the inverting end of the second inverter U13A. The positive end of the second inverter U13A is grounded. The second reverse proportional resistor R3 is connected between the output end and the inverting end of the second inverter U13A. The output of the second inverter U13A is connected to the output of the bidirectional amplitude conversion unit 40 after passing through the RC low-pass filter.

[0033] Specifically, the signal follower U13B realizes the signal following function, and the combination of the first inverter U13D and the second inverter U13A realizes the function of converting the positive and negative bidirectional signals into positive signals. For example, when the positive preset voltage or current signal reaches the 7th pin of the signal follower U13B, the first inverter U13D converts the positive analog signal into an equal-amplitude negative analog signal through the cooperation of the resistors R10, R5 and the reverse blocking diodes D5 and D7. At this time, the positive pole of the reverse blocking diode D7 is a negative analog signal, which is then converted into an equal-amplitude positive analog signal through the cooperation of the second inverter U13A and the resistors R14 and R3 to be transmitted to the output node TP5 of the bidirectional amplitude conversion unit. When the negative preset voltage or current signal reaches the 7th pin of the signal follower U13B, the first inverter U13D will not work, the resistor R5 and the reverse blocking diodes D5 and D7 form a parallel resistor Ra, the resistors R4, R10, Ra and R14 form a parallel resistor Rb, and the negative signal is converted into a positive analog signal of equal amplitude through the cooperation of the second inverter U13A and the parallel resistors Rb and R3 and transmitted to the output node TP5 of the bidirectional amplitude conversion unit 40. That is, the conditioning conversion of the positive and negative input signals to the positive signals of equal amplitude is realized, and the preset current signal and the preset voltage signal share a bidirectional amplitude conversion unit.

[0034] In this embodiment, the multifunctional preset current and voltage sampling circuit also includes an analog quantity isolation unit 50 composed of a linear optocoupler U17, and the analog quantity isolation unit 50 is connected between the sampling interface of the bidirectional amplitude conversion unit and the welding power supply control module 60. Specifically, the unit includes a comparator U13C, a linear optocoupler U17, and an amplifier U44 connected in sequence, and these three main components constitute the analog quantity isolation and transmission function. Pin 10 of the comparator U13C is connected to the output node TP5 of the bidirectional amplitude conversion unit 40 as a signal input, and its output is isolated by the linear optocoupler U17 and amplified by the amplifier U44, and then output to one of the ADC sampling interfaces of the DSP of the welding power supply control module 60 through the isolated output port TP6.

[0035] In order to better understand the working principle of the multifunctional preset current and voltage sampling circuit for gas shielded welding power supply provided in this example, the following will be combined with Figure 5 and Figure 6 The preset current and voltage signal sampling based on the single analog quantity interface J1 and the preset current and voltage sampling based on the dual analog quantity interface are described in detail.

[0036] Based on the preset current and voltage signal sampling of the single analog interface J1:

[0037] First, the input of the interface switching unit 30 is connected to the import node TP3 of the single analog interface J1.

[0038] When DSP_UI_SWITCH outputs a high level, the first acquisition switching signal UI_SWITCH outputs a low level, and the 1st pin of the comparator U31A outputs -15V (forming the second acquisition switching signal) to turn on D1, and the single analog interface J1 is connected to the ground potential GNDC through the voltage potentiometer VR1. At this time, the signal introduced into the node TP3 is a negative analog signal (negative preset voltage signal), and this signal is transmitted to the signal follower U13B for equal-value and equal-direction signal following. At this time, the first comparator U13D does not work, and the negative analog signal is converted into a positive equal-amplitude analog signal through the second comparator U13A, and then transmitted to the ADC sampling port of the DSP module after completing the signal isolation transmission through the analog isolation unit 50.

[0039] When DSP_UI_SWITCH outputs a low level, the first acquisition switching signal UI_SWITCH outputs a high level, and pin 1 of the comparator U31A outputs +15V (forming the second acquisition switching signal) to turn on D2, and the single analog interface J1 is connected to the ground potential GNDC via the current potentiometer VR2. At this time, the signal introduced into the node TP3 is a positive analog signal (positive preset current signal), and this signal is transmitted to the signal follower U13B for equal-value and equal-direction signal following. At this time, the first inverter U13D converts the positive analog signal into a negative equal-amplitude modulus signal, and then converts the negative analog signal into a positive equal-amplitude analog signal through the second inverter U13A, and then completes the signal isolation transmission through the analog isolation unit 50 and transmits it to the ADC sampling port of the DSP module. The timing diagram of the single analog input signal transmission is shown as follows: Figure 5 shown.

[0040] Based on the preset current and voltage signal sampling of the dual analog interface J2:

[0041] First, the input of the interface switching unit 30 is connected to the import node TP4 of the dual analog interface.

[0042] When DSP_UI_SWITCH outputs a high level, the first acquisition switching signal UI_SWITCH outputs a low level, the switch tube Q2 is turned on, the signal of pin 1 of the dual analog interface J2 is invalid, and the signal of pin 3 of the dual analog interface J2 is transmitted to the dual analog signal source import node TP4. At this time, the signal imported into node TP4 is a positive analog signal (positive preset voltage signal). This signal is transmitted to the signal follower U13B for equal-value and equal-direction signal following. At this time, the first inverter U13D converts the positive analog signal into a negative equal-amplitude modulus signal, and then converts the negative analog signal into a positive equal-amplitude analog signal through the second inverter U13A, and then completes the signal isolation transmission through the analog isolation unit 50 and transmits it to the ADC sampling port of the DSP module.

[0043] When DSP_UI_SWITCH outputs a low level, the first acquisition switching signal UI_SWITCH outputs a high level, the switch tube Q1 is turned on, the signal at pin 3 of the dual analog interface J2 becomes invalid, and the signal at pin 1 of the dual analog interface J2 is transmitted to the import node TP4. At this time, the signal at the import node TP4 is a positive analog signal (a positive preset current signal). This signal is transmitted to the follower U13B for equal-value and equal-direction signal following. At this time, the first inverter U13D converts the positive analog signal into a negative equal-amplitude analog signal, and then converts the negative analog signal into a positive equal-amplitude analog signal through the second inverter U13A. After the signal isolation transmission is completed through the analog isolation unit 50, it is transmitted to the ADC sampling port of the DSP module. The timing diagram of the dual analog input signal transmission is shown in the figure below. Figure 6 shown.

[0044] In summary, the utility model realizes the import of preset current signals and preset voltage signals on the wire feeder based on the acquisition switching signal output by the acquisition state switching unit and the two-way import path provided by the preset signal source import unit, and at the same time, the imported analog signals can be conditioned by the bidirectional amplitude conversion unit, so that only one sampling interface on the welding power supply control module is needed to complete the collection of all data during sampling. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply provided by the utility model realizes the integrated import of two-way analog signals, which not only greatly simplifies the circuit structure and reduces the cost, but also effectively reduces the use of limited external interfaces on the welding control module, saving interface resources. In addition, based on the setting of the single analog interface and the dual analog interface in the preset signal source import unit, the preset current source and preset voltage source on the wire feeder can be imported in the form of one analog signal or two analog signals, which greatly improves the flexibility of signal source import.

[0045] Although the present invention has been disclosed as above by the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope required by the claims.

Claims

1. A multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply, characterized in that: include: The acquisition state switching unit is configured to output at least one acquisition switching signal, each acquisition switching signal has two acquisition states corresponding to preset current acquisition and preset voltage acquisition on the wire feeder respectively; The preset signal source import unit includes an analog interface and two parallel import paths, the two import paths correspond to the preset current source and the preset voltage source on the wire feeder respectively, and each import path has a conducting element connected to the output end of the acquisition state switching unit; based on the control of the two acquisition states in the acquisition switching signal, only one import path is turned on at any time to import the preset current signal or preset voltage signal on the wire feeder; The bidirectional amplitude conversion unit includes at least one inverter to convert the preset current signal or preset voltage signal introduced by the preset signal source introduction unit into a positive analog signal and output it to the sampling interface of the welding power supply control module.

2. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 1, characterized in that: The analog quantity interface includes a single analog quantity interface and / or a dual analog quantity interface; the single analog quantity interface and the dual analog quantity interface are respectively connected to a preset current source and a preset voltage source on the wire feeder through two parallel introduction paths.

3. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 2 is characterized in that: The analog quantity interface includes a single analog quantity interface and a dual analog quantity interface, and the acquisition state switching unit outputs two acquisition switching signals to respectively control the conducting elements on the two parallel import paths corresponding to the two interfaces; the multifunctional preset current and voltage sampling circuit suitable for the gas shielded welding power supply also includes an interface switching switch unit, one side of the interface switching switch unit is alternately connected to the import of the single analog quantity interface and the dual analog quantity interface, and the other side is connected to the bidirectional amplitude conversion unit.

4. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 2 or 3, characterized in that: The outer side of the single analog interface is connected to the preset current source and preset voltage source on the wire feeder through two diodes with opposite conduction directions to form two parallel input paths, and the inner side of the interface is directly connected to the output end of the acquisition state switching unit.

5. The multifunctional preset current and voltage sampling circuit for gas shielded welding power supply according to claim 2 or 3, characterized in that: The outer side of the dual analog interface is directly connected to the preset current source and preset voltage source on the wire feeder. The two import paths are located on the inner side of the dual analog interface and both include an RC voltage divider filter network and a switch tube that connects the RC voltage divider filter network to the ground potential. The conduction conditions of the switch tubes on the two import paths are opposite. The output ends of the RC voltage divider filter network of the two import paths are both connected to the follower, and then connected to the bidirectional amplitude conversion unit after being followed by the follower.

6. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 3, characterized in that: The interface switching unit is one or more toggle switches; or one or more analog switches; or a multi-way switch circuit constructed by triodes.

7. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 1, characterized in that: The preset signal source import unit includes a signal transmission element and a comparator whose output amplitude is greater than the maximum adjustment amplitude of the two analog signal sources, the input end of the signal transmission element is connected to the IO port of the welding power supply control module, and a pulse signal is output based on the IO port. The signal transmission element outputs a first acquisition switching signal opposite to the pulse signal state to control the conduction elements on the two import paths of the dual analog interface; The first acquisition switching signal is connected to the comparator, and after being compared with the reference signal of the comparator, the second acquisition switching signal is output to control the conduction elements on the two import paths on the single analog interface.

8. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 7, characterized in that: The signal transmission element is an optical coupling isolation element; or a triode or a MOS tube.

9. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 1, characterized in that: The bidirectional amplitude conversion unit includes a signal follower, a first inverter and a second inverter which are connected in series in sequence. The signal follower follows the preset current signal or the preset voltage signal introduced by the preset signal source introduction unit to the inverting end of the first inverter. The positive end of the first inverter is grounded. The output end of the first inverter is connected to the reverse end of the second inverter. A reverse blocking diode and at least one first reverse proportional resistor are connected between the reverse end and the output end of the first inverter. The output of the first inverter is connected to the inverting end of the second inverter. The positive end of the second inverter is grounded. At least one second reverse proportional resistor is connected between the output end and the reverse end of the second inverter. The output of the second inverter is connected to the sampling interface of the welding power supply control module.

10. The multifunctional preset current and voltage sampling circuit suitable for gas shielded welding power supply according to claim 1 or 9, characterized in that: The multifunctional preset current and voltage sampling circuit suitable for the gas shielded welding power supply also includes an analog quantity isolation unit composed of linear optocouplers, and the analog quantity isolation unit is connected between the bidirectional amplitude conversion unit and the sampling interface of the welding power supply control module.

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