Measuring device and measuring method

Abstract

The present invention provides a measuring device and method that can reliably remove high-frequency, high-voltage noise at the start of arc welding and measure the voltage. [Solution] The measuring device is applied to arc welding using a welding machine. The measuring device comprises a measuring instrument for measuring the voltage of the welding machine, a detector for acquiring information to detect the generation and extinction of arc light, an insulating circuit that can be controlled to either an insulating state that insulates the welding machine and the measuring instrument, or an energized state that conducts electricity between the welding machine and the measuring instrument, and an insulating circuit control unit that detects either the generation or extinction of arc light based on the information acquired by the detector, and controls the insulating circuit to either an insulating state or an energized state according to the detected generation or extinction of arc light.

Description

Technical Field

[0001] The present disclosure relates to a measuring device and a measuring method.

Background Art

[0002] The shortage of skilled workers in manufacturing sites due to the declining birthrate and aging population has a great impact on the continuity of manufacturing operations, and there is a need to improve the efficiency of skilled worker training. Welding technology, which melts and joins metals, is essential for the manufacture of large structures. However, the actions of welders during manual welding are tacit knowledge and have not been well documented. Therefore, it is considered important in improving the efficiency of skilled worker training to construct an educational system that pre-acquires the actions of skilled welders during welding through various sensors, cameras, and voltage measurements and uses them for the skill training of beginners.

[0003] Here, measuring the welding voltage is important as a welding skill because the welding voltage strongly depends on the distance between the welded material and the tip of the welding torch and is strongly affected by the torch movement of the welder. That is, it is possible to indirectly evaluate the stability of the welder's torch movement by measuring the voltage profile. However, when trying to measure the welding voltage by a normal method using a data logger or the like, there is a problem that the voltage measuring instrument is damaged by the high-frequency high voltage at the time of arc ignition.

[0004] Regarding these problems, as a technique for measuring the welding voltage, Patent Document 1 describes a technique for switching a high-frequency voltage start and a high-voltage start as needed in order to provide a welding power supply device that can prevent the influence of high-frequency noise on other devices.

[0005] Further, Patent Document 2 describes a technique in which, for the purpose of providing a welding measurement system capable of suppressing the influence of high-frequency voltage or high voltage on a measuring instrument, the conductive member and the measuring instrument are in a cut-off state at the time of high-frequency voltage start, and when the current exceeds a threshold value, the conductive member and the measuring instrument are in a conductive state.

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-131260 [Patent Document 2] Japanese Patent Publication No. 2019-30898 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the conventional technologies described in Patent Documents 1 and 2 have the problem that it is difficult to implement technologies and equipment configurations that can reliably remove high-frequency, high-voltage noise at the start of arc welding for voltage measurement.

[0008] This disclosure was made to solve the above problems. Specifically, one of the objectives of this disclosure is to provide a measuring device and a measuring method that can reliably remove high-frequency, high-voltage noise at the start of arc welding and measure the voltage. [Means for solving the problem]

[0009] To solve the above problems, the measuring device of the present disclosure is a measuring device applied to arc welding by a welding machine, comprising: a measuring instrument for measuring the voltage of the welding machine; a detector for acquiring information for detecting the generation and extinction of arc light; an insulating circuit that can be controlled to either an insulating state in which the welding machine and the measuring instrument are insulated, or an energized state in which the welding machine and the measuring instrument are electrically connected; and an insulating circuit control unit that detects either the generation or extinction of arc light based on the information acquired by the detector, and controls the insulating circuit to either the insulating state or the energized state according to the detected generation or extinction of arc light.

[0010] The measurement method of this disclosure is applied to arc welding using a welding machine and is a measurement method using a measuring device comprising a measuring instrument, a detector, an insulating circuit, and an insulating circuit control unit, wherein the measuring instrument measures the voltage of the welding machine, the detector acquires information for detecting the generation and extinction of arc light, the insulating circuit controls the system to either an insulating state that insulates the welding machine and the measuring instrument, or an energized state that conducts electricity between the welding machine and the measuring instrument, the insulating circuit control unit detects either the generation or extinction of arc light based on the information acquired by the detector, and controls the insulating circuit to either the insulating state or the energized state according to the detected generation or extinction of arc light. [Effects of the Invention]

[0011] According to this disclosure, high-frequency, high-voltage noise at the start of arc welding can be reliably removed, and the voltage can be measured. The effects described herein are not necessarily limited, and any of the effects described herein may be present. Furthermore, other problems, configurations, and effects will be clarified by the following description of embodiments for carrying out the invention. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of the measuring device according to the embodiment. [Figure 2] Figure 2 shows an example of the configuration of the determination unit and the measurement unit. [Figure 3] Figure 3 is a schematic diagram of the measuring device including the step-down circuit. [Figure 4] Figure 4 is a flowchart showing the operation of the measuring device according to the embodiment. [Figure 5] Figure 5 is an explanatory diagram illustrating the relationship between brightness, trigger signal, and welding voltage according to the embodiment. [Figure 6] Figure 6 is a flowchart showing the image processing operation according to the embodiment. [Figure 7]FIG. 7 is a diagram showing a modified example of the determination unit and the measurement unit. [Figure 8] FIG. 8 is a schematic configuration diagram of a measuring device according to a modified example.

Embodiments for Carrying Out the Invention

[0013] First, to facilitate understanding of the present disclosure, the details of the problems of the present disclosure will be described. In non-consumable electrode arc welding, it is of course necessary to ignite an arc (the exact term is "arc starting") at the start of welding.

[0014] However, since the surface of the workpiece is often oxidized, the "high-frequency voltage start method" or the "high-voltage start method" is used to break the insulation between the workpiece and the electrode. On the other hand, there is also an "electrode contact method" in which the electrode is brought into contact and then slightly lifted to start an arc. However, the electrode contact method is difficult in manual arc welding because the electrode needs to be slightly lifted immediately after energization, and it is often applied to automatic welding using a robot. That is, in current manual arc welding, arc starting by the high-frequency high-voltage method or the DC high-voltage method is the center, and the generation of high-frequency high-voltage noise at the start of welding is inevitable.

[0015] The prior art described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2020-131260) switches between the high-frequency high-voltage method and the DC high-voltage method, and can only be used for welding machines equipped with only high-frequency voltage start. Also, since a voltage of several kV is generated during high-voltage start, the problem of the measuring instrument being damaged remains.

[0016] The prior art described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2019-30898) is such that the measuring instrument is in a cut-off state during high-frequency voltage start, and when the current exceeds the threshold value, the conductive member and the measuring instrument are in an energized state. Therefore, the influence of high-frequency high-voltage noise at start can be prevented.

[0017] However, the prior art of Patent Document 2 has a device configuration that uses the welding current as a threshold value, and since the arithmetic unit and the cutoff unit are the same, the arithmetic unit that calculates the threshold value may malfunction due to the influence of noise. Further, as described in FIG. 3 of Patent Document 2, the welding current may peak as noise when a high-frequency high voltage is applied at the start of arc welding, and if the threshold value is not appropriately set with respect to the current value and its holding time, there is a risk of inducing a malfunction. As a result of the malfunction, the welding machine and the measuring instrument may be connected at an incorrect timing, and the measuring instrument may be damaged.

[0018] Such prior arts described in Patent Document 1 and Patent Document 2 may impair voltage measurement that stably removes high-frequency high voltage noise at the start of arc welding, and a technique or device configuration for realizing voltage measurement that stably removes high-frequency high voltage noise at the start of arc welding is desired.

[0019] In recent years, sensors and information processing devices have advanced significantly, and it has become possible to apply processing and control using these even at manufacturing sites where the hurdle for introduction was previously high. The present disclosure aims to measure a voltage profile during welding that is more stable than known examples using these devices, particularly cameras and image processing devices.

[0020] That is, the present disclosure has been made to solve the above-described problems, and the main object is to provide a technique and a device configuration for realizing voltage measurement that stably removes high-frequency high voltage noise at the start of arc welding.

[0021] Hereinafter, embodiments of the present disclosure (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings. Note that each drawing only schematically shows the present disclosure to an extent that can be sufficiently understood. Therefore, the present disclosure is not limited to only the illustrated examples. Also, in each drawing, common components and similar components are denoted by the same reference numerals, and duplicate descriptions thereof are omitted.

[0022] The embodiments (examples) are illustrative examples for illustrating the present disclosure and have been omitted and simplified as appropriate for clarity of explanation. The present disclosure can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0023] The positions, sizes, shapes, and extents of the components shown in the drawings may not represent their actual positions, sizes, shapes, and extents in order to facilitate understanding of the invention. Therefore, this disclosure is not necessarily limited to the positions, sizes, shapes, and extents disclosed in the drawings.

[0024] In the embodiments (examples), the processing performed by executing a program may be described. Here, the computer executes the program using a processor (e.g., CPU, GPU) and performs the processing defined in the program using memory resources (e.g., memory) and interface devices (e.g., communication ports). Therefore, the main entity performing the processing by executing the program may be the processor. Similarly, the main entity performing the processing by executing the program may be a controller, device, computer, etc., that has a processor. The main entity performing the processing by executing the program may be an arithmetic unit, and may include a dedicated circuit that performs a specific processing. Here, a dedicated circuit is, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a CPLD (Complex Programmable Logic Device), etc.

[0025] The program may be installed on the computer from the program source. The program source may be, for example, a program distribution server or a storage medium readable by the computer. If the program source is a program distribution server, the program distribution server includes a processor and storage resources for storing the program to be distributed, and the processor of the program distribution server may distribute the program to other computers. In addition, in the embodiment, two or more programs may be implemented as one program, or one program may be implemented as two or more programs.

[0026] <Configuration of the measuring device> The configuration of the measuring device 100 according to this embodiment will be described below with reference to Figure 1. Figure 1 is a schematic diagram of the measuring device 100 according to this embodiment.

[0027] As shown in Figure 1, the measuring device 100 according to this embodiment comprises a welding machine 10, a measuring unit 20, and a determination unit 30. A welder 101 performing manual welding is also shown for reference (however, the welder 101 is not an essential component).

[0028] The welding machine 10 is a device for welding the workpiece 12. The welding machine 10 consists of a power supply unit 11, a welding torch 13, and an electrode 14.

[0029] The power supply unit 11 supplies the current and voltage necessary for arc generation to the welding torch 13. The power supply unit 11 also includes a circuit that generates high-frequency high voltage, which ignites the arc at the start of welding.

[0030] The welding torch 13 is a component that generates an arc on the workpiece 12. The welding torch 13 is held by the welder 101, and welding is performed on the workpiece 12. The electrode 14 is the part that emits the arc, located at the lower end of the welding torch 13.

[0031] The determination unit 30 includes a detector 31 that detects the generation and extinction of arc light, and an isolation circuit control unit 32 that generates a trigger in response to the generation and extinction.

[0032] The detector 31 can be any device capable of detecting the generation and extinction of arc light (or acquiring information for detecting the generation and extinction of arc light), such as a camera or luminance sensor, which are imaging devices capable of capturing images. Because arc light is very strong, its generation and extinction can be clearly detected by a luminance sensor. When a luminance sensor is used as the detector 31, the amount of light is converted into a luminance value and transmitted to the isolation circuit control unit 32.

[0033] Even when using a camera as the detector 31, there is a light intensity that causes the image to go outside the measurement range ("overexposure"), so detection is possible simply by providing an image processing method that can detect such overexposure. When using a camera as the detector 31, the video is transmitted sequentially to the isolation circuit control unit 32. On the other hand, if the arc light is completely blocked by the welder 101 or some kind of shielding, the robustness of detection can be improved by installing two or more detectors 31.

[0034] The isolation circuit control unit 32 acquires information from the detector 31 and generates a "trigger signal" based on the information acquired from the detector 31. Specifically, when an arc occurs, if the signal from the detector 31 exceeds a threshold, an ON trigger signal is generated. When the arc disappears, if the signal from the detector 31 is below the threshold, an OFF trigger signal is generated. The ON trigger signal is a signal indicating the occurrence of arc light and may be referred to as the "first trigger signal." The OFF trigger signal is a signal indicating the disappearance of arc light and may be referred to as the "second trigger signal."

[0035] The isolation circuit control unit 32 can be configured by a computer including a processor such as a CPU and a storage device (storage medium) such as memory. The computer's processor implements the functions of the isolation circuit control unit 32 by executing a program. The isolation circuit control unit 32 can also be configured in whole or in part by hardware such as circuit devices.

[0036] If the detector 31 is a camera, image processing is also performed inside the isolated circuit control unit 32. That is, the information (image) sent sequentially from the camera is converted into information that can be compared with a threshold ("luminance equivalent information") by image processing. If the converted luminance equivalent information exceeds the threshold, an ON trigger signal is generated, and if it is lower than the threshold, an OFF trigger signal is generated. The image processing method will be explained in the embodiment.

[0037] The measuring unit 20 consists of an isolation circuit 21 that can switch the isolation state by a trigger and a measuring instrument 22.

[0038] The isolation circuit 21 receives a trigger signal from the isolation circuit control unit 32 and switches between an isolation state and an energized state. Normally, it is in an isolation state, and when it receives an ON trigger signal due to arc generation, it switches to an energized state. When energized, the voltage profile can be measured with the measuring instrument 22. When it receives an OFF trigger signal due to arc extinguishing, it returns to the isolation state. These components must be able to withstand high frequency and high voltage, and for example, the use of a voltage-resistant relay circuit that operates when a specific trigger signal is input is envisioned.

[0039] Figure 2 shows an example configuration of the determination unit 30 and measurement unit 20 using a relay circuit. The isolation circuit 21 includes a relay circuit that includes a contact 201, a coil unit 202, and a signal switch 203.

[0040] Contact 201 is controlled to be either ON (conductive) or OFF (non-conductive). When contact 201 is OFF, the insulating circuit 21 is in an insulated state, insulating the measuring instrument 22 from the welding machine 10. When contact 201 is ON, the insulating circuit 21 is in an energized state, allowing current to flow (conductivity) between the measuring instrument 22 and the welding machine 10.

[0041] The signal switch 203 turns ON (conductive) when an ON trigger signal is input from the isolation circuit control unit 32, and turns OFF (non-conductive) when an OFF trigger signal is input from the isolation circuit control unit 32.

[0042] When the signal switch 203 is turned ON, current flows through the coil section 202, and the contact 201 turns ON. When the signal switch 203 is turned OFF, no current flows through the coil section 202, and the contact 201 turns OFF. In the configuration shown in Figure 2, the determination unit 30 is isolated from the voltage path used to measure the voltage of the welding machine 10, which is provided between the welding machine 10 and the measuring instrument 22. As a result, the isolation circuit control unit 32 is isolated so that the voltage output from the welding machine 10 is not input to it. Therefore, the high-frequency high voltage during arc ignition is not transmitted to the determination unit 30 (detector 31 and isolation circuit control unit 32), and the determination unit 30 (detector 31 and isolation circuit control unit 32) is not affected by the high-frequency high voltage during arc ignition.

[0043] The measuring instrument 22 measures the voltage profile during welding, and a data logger that can obtain a high sampling rate is preferable. This is because the voltage profile reflects the torch movement of the welder 101, and abrupt torch movements can cause welding defects. If the expected voltage is higher than the withstand voltage of the measuring instrument 22, for example, a circuit that reduces the voltage to 1 / 10 is used to reduce the input voltage, and then the actual voltage is calculated by multiplying it by 10 during data processing. (However, the step-down circuit is not a mandatory configuration.) For example, as shown in Figure 3, the measuring device 100 may have a configuration in which a step-down circuit 23 is added between the isolation circuit 21 and the measuring instrument 22.

[0044] <Examples> The operation of the measuring device 100 according to this embodiment will be described below with reference to the flowchart in Figure 4 and the sequence diagram in Figure 5.

[0045] In S01 of Figure 4, the luminance measurement by the detector 31 is initiated. To prevent any malfunctions, it is preferable to start the luminance measurement immediately before the voltage measurement.

[0046] In S02, in the case of manual welding, the welder 101 prepares for welding and attempts to ignite the arc. Generally, pressing the switch on the welding torch 13 applies a high-frequency high voltage to ignite the arc (Figure 5a). At this time, the measuring instrument 22 is electrically insulated by the insulating circuit 21, so it is not subjected to high-frequency high voltage and is not damaged.

[0047] In S03, before arc generation, the brightness measured by the detector 31 does not exceed the threshold (b in Figure 5), so the isolation circuit control unit 32 does not generate an ON trigger signal.

[0048] In S04, when the brightness exceeds the threshold due to arc generation (c in Figure 5), an ON trigger signal is generated by the isolation circuit control unit 32 (d in Figure 5). Then, when the arc is ignited, the voltage drops from a high-frequency voltage of several tens of kV to a voltage of several tens of V required for welding (e in Figure 5). This is a voltage that can be measured with a general measuring instrument.

[0049] In S05, the isolation circuit 21 receives the ON trigger signal and switches from the isolation state to the energized state (f in Figure 5). As a result, the welding voltage is applied to the measuring instrument 22, and the voltage profile during welding can be measured. Normally, the welder 101 does not move the torch when the high-frequency high voltage is applied, but moves the torch after the arc is lit, so there is no data loss other than the voltage value of the high-frequency high voltage. After that, the welder 101 performs arc welding for a certain period of time.

[0050] In S06, after welding for a certain period of time, the welder 101 extinguishes the arc at the end of welding (g in Figure 5). Generally, the arc is extinguished by the welder 101 pressing the switch on the welding torch 13 again. At this time, if the arc is extinguished abruptly, a crack (crater crack) will occur at the end of the weld, so a method of gradually lowering the current and voltage values ​​(crater treatment) is often adopted. In S07, when the brightness falls below a threshold (h in Figure 5), an OFF trigger signal is generated by the isolation circuit control unit 32 (i in Figure 5).

[0051] In S08, upon receiving the OFF trigger signal, the isolation circuit 21 switches back to the isolation state (j in Figure 5), electrically isolating the welding machine 10 and the measuring instrument 22. This completes the measurement of the voltage profile.

[0052] In S08, the brightness measurement by the detector 31 is also completed. To prevent any malfunctions, it is preferable to complete the brightness measurement immediately after the voltage measurement.

[0053] <An example of an image processing method> Next, the image processing operation according to the embodiment when a camera is used as the detector 31 will be explained with reference to the flowchart in Figure 6. This process corresponds to S03 in the flowchart of Figure 4, and the internal processing will be explained in detail.

[0054] In S3-1, image processing begins.

[0055] In S3-2, the isolation circuit control unit 32 acquires one image at time tn.

[0056] In S3-3, the average brightness of each pixel in the image is calculated sequentially. That is, the average brightness Bave,j of the j-th pixel in the image is calculated. Various methods have been proposed for calculating the average brightness, but for example, in a color image composed of RGB, the calculation method using formula (1) is assumed. Bave,j = 1 / 3R+ 1 / 3G+ 1 / 3B...Formula (1)

[0057] In steps S3-4, it is determined whether the average brightness for all pixels in the image has been calculated. If there are any uncalculated pixels, j is added and the calculation continues. Once all pixels have been processed, the process proceeds to step S3-5.

[0058] In S3-5, the average brightness of all pixels is summed up and averaged to calculate the average brightness of the image at time tn, Bave-all,n (i.e., calculated using formula (2)). Bave-all,n = Σ Bave,j / Total number of pixels...Calculation formula (2)

[0059] In S3-6, the average brightness Bave-all,n is compared with the threshold Bs. Because the arc emits very strong light, the brightness differs significantly before and after firing. Therefore, the threshold Bs can be easily determined. If the average brightness Bave-all,n does not exceed the threshold Bs, the process returns to S3-2 and the average brightness at time tn+1 is calculated again. If the average brightness Bave-all,n exceeds the threshold Bs, the process proceeds to S3-7.

[0060] In S3-7, the isolation circuit control unit 32 outputs an ON trigger signal to the isolation circuit 21, the isolation circuit 21 becomes energized, and voltage measurement begins.

[0061] The process described above is for when the ON trigger signal is output, but the same process is applied when the OFF trigger signal is output. Only the comparison with the threshold Bs is reversed; if the average brightness Bave-all,n falls below the threshold Bs, the OFF trigger signal is output and image processing ends.

[0062] According to the measuring device 100 of this embodiment, the isolation circuit 21 and the determination unit 30 (detector 31 and isolation circuit control unit 32) can be separated, making it possible to measure voltage that is less susceptible to high-frequency, high-voltage noise. Furthermore, since this disclosure is triggered by the clear occurrence of an arc as a phenomenon, the brightness threshold is clear. Therefore, there is no need to determine the current value and time thresholds, and malfunctions due to inappropriate thresholds do not occur.

[0063] This allows for stable measurement of the voltage profile during welding, which can be useful for welding skills training. Furthermore, since welding voltage is a parameter that affects the amount of heat input to the welding material, obtaining the voltage profile is considered important from a quality control perspective.

[0064] Furthermore, the measurement device 100 of the embodiment provides the following effects (1) and (2): (1) Voltage measurement that is less susceptible to high-frequency high-voltage noise becomes possible. This is because, while Patent Document 2 (JP 2019-30898 A) requires the calculation unit to be incorporated into the insulation unit, the present disclosure allows the insulation circuit 21 and the determination unit 30 (detector 31 and insulation circuit control unit 32) to be separate. (2) Since there is no need to determine thresholds (current value and time), malfunctions due to inappropriate thresholds do not occur. This is because, while Patent Document 2 (JP 2019-30898 A) may malfunction if the current and time thresholds are not appropriately determined, the present disclosure uses the clear phenomenon of arc generation as a trigger, so there is no need to determine these.

[0065] This disclosure is not limited to the embodiments described above, but includes various modifications. For example, the embodiments described above are described in detail for the purpose of explaining this disclosure and are not necessarily limited to having all the configurations described. Furthermore, it is possible to replace some of the configurations of the embodiments with other configurations, and it is also possible to add other configurations to the configurations of the embodiments. In addition, it is possible to add, delete, or replace some of the configurations of each configuration with other configurations.

[0066] Figure 7 shows a modified example of the configuration of the determination unit 30 and the measurement unit 20 using a relay circuit. As shown in Figure 7, the determination unit 30 includes a detector 31, an isolation circuit control unit 32, a coil unit 301, and a signal switch 302.

[0067] The insulating circuit 21 includes a contact 201. The contact 201 is controlled to be either ON (conductive) or OFF (non-conductive). When the contact 201 is OFF, the insulating circuit 21 is in an insulating state, insulating the measuring instrument 22 from the welding machine 10. When the contact 201 is ON, the insulating circuit 21 is in an energized state, allowing current to flow between the measuring instrument 22 and the welding machine 10.

[0068] The signal switch 302 turns ON (conductive) when an ON trigger signal is input from the isolation circuit control unit 32, and turns OFF (non-conductive) when an OFF trigger signal is input from the isolation circuit control unit 32.

[0069] When the signal switch 302 is turned ON, current flows through the coil section 301, and the contact 201 turns ON. When the signal switch 302 is turned OFF, no current flows through the coil section 301, and the contact 201 turns OFF. In this modified example, the determination section 30 and the measurement section 20 are insulated, and the determination section 30 is insulated from the voltage path used to measure the voltage of the welding machine 10, which is provided between the welding machine 10 and the measuring instrument 22. Therefore, the high-frequency high voltage during arc ignition is not transmitted to the determination section 30, and the determination section 30 is not affected by the high-frequency high voltage.

[0070] This disclosure may also take the following configuration.

[0071] [1] A measuring device applied to arc welding using a welding machine, A measuring instrument for measuring the voltage of the welding machine, A detector that acquires information for detecting the generation and extinction of arc light, An insulating circuit that can be controlled to either an insulating state that insulates the welding machine and the measuring instrument, or an energized state that conducts electricity between the welding machine and the measuring instrument, An isolation circuit control unit detects either the generation of the arc light or the extinction of the arc light based on the information acquired by the detector, and controls the isolation circuit to either the isolation state or the energized state according to which of the detected generation of the arc light or the extinction of the arc light is detected, Equipped with, Measuring device.

[0072] [2] In the measuring device described in [1], The detector is a current sensor that acquires the welding current as information for detecting the generation and extinction of the arc light. Measuring device. [2] An example of the configuration when the configuration is adopted is shown in Figure 8. As shown in Figure 8, the measuring device 100 has a determination unit 30 which is equipped with a current sensor 33. The current sensor 33 measures the welding current and inputs it to the isolation circuit control unit 32. Based on the welding current, the isolation circuit control unit 32 detects either the generation of arc light or the extinction of arc light.

[0073] [3] A measurement method applicable to arc welding using a welding machine, which uses a measuring device equipped with a measuring instrument, a detector, an insulating circuit, and an insulating circuit control unit, The voltage of the welding machine is measured using the aforementioned measuring instrument. The detector acquires information for detecting the generation and extinction of arc light. The aforementioned insulating circuit controls the welding machine and the measuring instrument to either an insulating state, which insulates them from each other, or an energized state, which conducts electricity between the welding machine and the measuring instrument. The isolation circuit control unit detects either the generation of the arc light or the extinction of the arc light based on the information acquired by the detector, and controls the isolation circuit to either the isolation state or the energized state according to the detected generation of the arc light or the extinction of the arc light. Measurement method. [Explanation of Symbols]

[0074] 10...Welding machine, 11...Power supply unit, 12...Material to be welded, 13...Welding torch, 14...Electrode, 20...Measurement unit, 21...Insulation circuit, 22...Measuring instrument, 30...Determination unit, 31...Detector, 32...Insulation circuit control unit, 100...Measurement device, 101...Welder

Claims

1. A measuring device applied to arc welding using a welding machine, A measuring instrument for measuring the voltage of the welding machine, A detector that acquires information for detecting the generation and extinction of arc light, An insulating circuit that can be controlled to either an insulating state that insulates the welding machine and the measuring instrument, or an energized state that conducts electricity between the welding machine and the measuring instrument, An isolation circuit control unit detects either the generation of the arc light or the extinction of the arc light based on the information acquired by the detector, and controls the isolation circuit to either the isolation state or the energized state according to which of the detected generation of the arc light or the extinction of the arc light is detected, Equipped with, Measuring device.

2. In the measuring device according to claim 1, The isolation circuit control unit is isolated from the voltage path for measuring the voltage of the welding machine, which is provided between the welding machine and the measuring instrument. Measuring device.

3. In the measuring device according to claim 1, The isolation circuit control unit generates trigger signals corresponding to the detection of the generation and extinction of the arc light, and controls the state of the isolation circuit to either the isolation state or the energized state based on the trigger signals. Measuring device.

4. In the measuring device according to claim 1, When the isolation circuit control unit detects the occurrence of the arc light, it generates a first trigger signal indicating the occurrence of the arc light, and controls the isolation circuit to switch from the isolation state to the energized state based on the first trigger signal. When the extinction of the arc light is detected, a second trigger signal indicating the extinction of the arc light is generated, and the isolation circuit is controlled by the second trigger signal to switch from the energized state to the isolated state. Measuring device.

5. In the measuring device according to claim 3, The detector is a brightness sensor that acquires brightness as information for detecting the generation and extinction of the arc light. The isolation circuit control unit acquires the brightness obtained by the brightness sensor and detects either the generation of the arc light or the extinction of the arc light by comparing the brightness with a threshold value. Measuring device.

6. In the measuring device according to claim 3, The detector is an imaging device that acquires an image as information for detecting the generation and extinction of the arc light. The isolation circuit control unit acquires the image obtained by the imaging device, calculates brightness equivalent information by performing image processing on the image, and detects either the generation of the arc light or the extinction of the arc light by comparing the brightness equivalent information with a threshold. Measuring device.

7. In the measuring device according to claim 1, The device includes a step-down circuit that steps down the voltage from the welding machine and inputs it to the measuring instrument. Measuring device.

8. In the measuring device according to claim 1, The detector is a current sensor that acquires the welding current as information for detecting the generation and extinction of the arc light. Measuring device.

9. In the measuring device according to claim 1, The detector comprises two or more of the above-mentioned detectors. Measuring device.

10. In the measuring device according to claim 3, The isolation circuit includes a relay circuit that controls the state of the isolation circuit to either the isolation state or the energized state based on the trigger signal. Measuring device.

11. A measurement method applicable to arc welding using a welding machine, which uses a measuring device equipped with a measuring instrument, a detector, an insulating circuit, and an insulating circuit control unit, The voltage of the welding machine is measured using the aforementioned measuring instrument. The detector acquires information for detecting the generation and extinction of arc light. The aforementioned insulating circuit controls the welding machine and the measuring instrument to either an insulating state, which insulates them from each other, or an energized state, which conducts electricity between the welding machine and the measuring instrument. The isolation circuit control unit detects either the generation of the arc light or the extinction of the arc light based on the information acquired by the detector, and controls the isolation circuit to either the isolation state or the energized state according to the detected generation of the arc light or the extinction of the arc light. Measurement method.

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