Digital sampling conversion circuit of welding machine

Abstract

A digital sampling conversion circuit of a welding machine comprises a current sampling module, a voltage sampling module, a control module, a communication module and the like. The input end of the current sampling module is connected with a current Hall sensor arranged at a welding machine, and the current sampling module is used for amplifying and dividing a current signal of the current Hall sensor and then sending the current signal to the ADC input end of the control module; the voltage sampling module is used for converting the voltage output by the welding machine, converting a voltage signal converted by the second voltage dividing unit into a group of differential signals, converting the differential signals into single-end signals, and sending the single-end signals to the ADC input end of the control module; and the control module is connected with the communication module and is used for performing analog-to-digital conversion on signals which are transmitted by the current sampling module and the voltage sampling module and are acquired by the ADC input end and then uploading the signals to an upper computer through the communication module. According to the scheme, current and voltage key parameters can be sampled, converted and monitored for welding which cannot be directly accessed to a management system in the prior art, and the replacement cost can be saved.

Description

Technical Field

[0001] The present application relates to welding machine parameter monitoring technology, and in particular to a welding machine digital sampling and conversion circuit. Background Art

[0002] As the country promotes the development of intelligent and networked equipment, more and more welding equipment needs IoT monitoring. Now the new welding machine adopts digital design and has networking function, which is not compatible with old equipment. However, many old welding machines and old equipment cannot be connected to the management system and face the risk of being eliminated. If the intelligent management and related parameters of old welding equipment can be realized, the replacement cost can be saved and the maintenance efficiency can be improved. Utility Model Content

[0003] In order to solve the above-mentioned deficiencies of the prior art, the present application provides a digital sampling and conversion circuit for a welding machine, which is used to sample and convert key parameters of current and voltage of traditional welding machines that cannot be directly connected to a management system, thereby realizing monitoring and saving replacement costs.

[0004] In order to achieve the above purpose, the utility model adopts the following technologies:

[0005] A welding machine digital sampling and conversion circuit comprises a current sampling module, a voltage sampling module, a control module, a communication module and the like.

[0006] The input end of the current sampling module is connected to the current Hall sensor provided at the welding machine, and the output end is connected to the control module. The current sampling module is used to amplify and divide the current signal of the current Hall sensor and then send it to the ADC input end of the control module. Further, the current sampling module includes an operational amplifier U115 and a first voltage divider unit connected in sequence. Pin 3 of the operational amplifier U115 is connected to the current Hall sensor at the welding machine through the connector CN11, pin 2 is connected to GND, pin 1 is connected to pin 5, pin 4 is connected to +5V and one end of the capacitor C225, and the other end of the capacitor C225 is connected to GND. The first voltage divider unit is connected to pin 1 of the operational amplifier U115 and the ADC input end of the control module.

[0007] The voltage sampling module includes a second voltage dividing unit, an isolated voltage sampling chip U113, and an operational amplifier U114 which are connected in sequence. The second voltage dividing unit is connected to the positive and negative terminals of the welding machine output. The operational amplifier U114 is connected to the control module. The second voltage dividing unit is used to convert the voltage output by the welding machine. The isolated voltage sampling chip U113 is used to convert the voltage signal converted by the second voltage dividing unit into a group of differential signals. The operational amplifier U114 is used to convert a group of differential signals into single-ended signals and then send them to the ADC input end of the control module.

[0008] The control module is connected to the communication module, and is used to convert the signals transmitted by the current sampling module and the voltage sampling module obtained by the ADC input end into analog-to-digital signals, and then upload them to the host computer through the communication module. Further, the control module includes a microcontroller U69, and the communication module includes an RS485 isolation module U116, a protection unit, and a common mode filter unit connected in sequence. Pins 3 and 4 of the RS485 isolation module U116 are respectively connected to the 485_TX pin and the 485_RX pin of the microcontroller U69, pin 2 of the RS485 isolation module U116 is connected to GND, pin 1 of the RS485 isolation module U116 is connected to +5V, pin 10 of the RS485 isolation module U116 is connected to AGND, pins 9 and 8 of the RS485 isolation module U116 are connected to the protection unit, and the output end of the common mode filter unit is connected to the host computer through the host computer terminal, and the output end of the common mode filter unit is connected in parallel with a bus terminal resistor R264.

[0009] The beneficial effects of the utility model are:

[0010] 1. Collect the key parameters of current and voltage of traditional welding machines, convert them, and connect them to the host computer through RS485 bus to monitor the continued operation of old equipment and save replacement funds;

[0011] 2. The microcontroller U69 provides control for the entire circuit, the isolated voltage sampling chip U113 is used to collect the voltage of the traditional welding machine, the operational amplifier and the current Hall sensor are used to collect the current of the traditional welding machine, and the converted current is sent to the ADC port. The isolated RS485 module TD501D485H-A is used to provide 485 bus support for the system. The microcontroller U69 converts the collected analog current and voltage of the welding machine into digital quantities, and the control program packages and converts the data into ModBus protocol data. The upper computer monitoring software or the Internet of Things system exchanges data with the system through the RS485 bus, thereby realizing intelligent supervision of the traditional welding machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a block diagram of the overall structure of the welding machine digital sampling and conversion circuit according to an embodiment of the present application.

[0013] Figure 2 This is an example diagram of the circuit principle of the current sampling module of an embodiment of the present application.

[0014] Figure 3 This is an example diagram of the circuit principle of the voltage sampling module in an embodiment of the present application.

[0015] Figure 4 This is an example diagram of the control module circuit principle of an embodiment of the present application.

[0016] Figure 5 This is an example diagram of the communication module circuit principle of an embodiment of the present application.

[0017] Figure 6 This is an example diagram of the power module circuit principle of an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings, but the embodiments described in the utility model are only part of the embodiments of the utility model, rather than all the embodiments.

[0019] The present application embodiment provides a welding machine digital sampling and conversion circuit, which is used to sample, convert and upload the current and voltage parameters of a traditional (old / outdated) welding machine, such as Figure 1 As shown, it includes a current sampling module, a voltage sampling module, a control module, a communication module, and a power supply module.

[0020] Among them, the power module is used to provide +5V and +3.3V voltages for the circuit, the input end of the current sampling module is connected to the current Hall sensor installed at the welding machine, and the output end is connected to the control module. The current sampling module is used to amplify and divide the current signal of the current Hall sensor and send it to the ADC input end of the control module; the input end of the voltage sampling module is connected to the positive and negative terminals of the welding machine output, and the output end is connected to the control module, which is used to step down the voltage output by the welding machine, convert it into a set of differential signals through isolated voltage sampling, and then convert it into a single-ended signal and send it to the ADC input end of the control module. The control module is connected to the communication module, which is used to convert the signals transmitted by the current sampling module and the voltage sampling module obtained at the ADC input end into analog-to-digital conversion, and then upload them to the host computer through the communication module.

[0021] like Figure 6 As shown, the power module includes a part that provides +5V and a part that provides +3.3V, which are respectively implemented by the DC / DC chip U112 and the linear voltage regulator chip LDO2. Specifically, the 4th pin of the DC / DC chip U112 is connected to +24V through the resistor R240, the 5th pin is connected to +24V and one end of the capacitor C217, and the other end of the capacitor C217 is connected to GND, the 6th pin is connected to the 1st pin through the capacitor C220, the 2nd pin is connected to the positive electrode of the diode D36, and the negative electrode of the diode D36 is connected to the 6th pin. The 6th pin is also connected to one end of the inductor L12, and the other end of the inductor L12 is connected to one end of the inductor R239, the positive end of the capacitor C219, and one end of the capacitor C218, which is the +5V output end. The other end of the resistor R239 is connected to the 3rd pin and one end of the resistor R238, and the other end of the resistor R238 is connected to the 2nd pin, the negative end of the capacitor C219, the other end of the capacitor C218, and GND. Optionally, the DC / DC chip U112 uses ME3116AM6G.

[0022] Optionally, the linear voltage regulator chip LDO2 adopts ME6211C33M5G-N, whose pins 1 and 3 are connected to +5V and connected to one end of capacitor C210, and the other end of capacitor C210 is connected to GND and pin 2, pin 4 of the linear voltage regulator chip LDO2 is suspended, pin 5 outputs +3.3V, and is connected to one end of capacitor C211, the positive end of capacitor C212, one end of capacitor C213, one end of capacitor C214, one end of capacitor C215, and one end of capacitor C216, and the other end of capacitor C211, the negative end of capacitor C212, the other end of capacitor C213, the other end of capacitor C214, the other end of capacitor C215, and the other end of capacitor C216 are connected to GND.

[0023] Specifically, the DC24V enters the power module, is first converted into DC5V by the DC / DC chip U112 to power the circuit, and then the DC5V is converted into DC3.3V by the linear voltage regulator chip LDO2 to power the control module.

[0024] like Figure 4 As shown, the control module includes a microcontroller U69, which optionally uses GD32F303CCT6. Among them, the resistor R162 and the capacitor C151 form a reset circuit, one end of the resistor R162 is connected to +3.3V, and the other end is connected to one end of the capacitor C151 and the 7th pin of the microcontroller U69, and the other end of the capacitor C151 is connected to GND. The 10th, 11th and 12th pins of the microcontroller U69 are ADC input pins, and the 30th and 31st pins are 485_TX and 485_RX pins respectively. The control module is also provided with a light-emitting diode LED3 and a light-emitting diode LED6 as a status indicator. The positive pole of the light-emitting diode LED3 is connected to +3.3V through a resistor R87, and the negative pole is connected to the 33rd pin of the microcontroller U69. The positive pole of the light-emitting diode LED6 is connected to +3.3V through a resistor R211, and the negative pole is connected to the 32nd pin of the microcontroller U69. The resistor R22, the resistor R21 and the connector CN3 constitute a SW program download circuit. One end of the resistor R22 is connected to the 47th pin of the microcontroller U69 and the connector CN3, and the other end is connected to GND. One end of the resistor R21 is connected to +3.3V, and the other end is connected to the 34th pin of the microcontroller U69 and the connector CN3.

[0025] like Figure 2 As shown, the current sampling module includes an operational amplifier U115 and a first voltage divider unit connected in sequence, pin 3 of the operational amplifier U115 is connected to the current Hall sensor at the welding machine through the connector CN11, pin 2 is connected to GND, pin 1 is connected to pin 5, pin 4 is connected to +5V and one end of the capacitor C225, and the other end of the capacitor C225 is connected to GND, and the first voltage divider unit is connected to pin 1 of the operational amplifier U115 and the ADC input end of the control module, specifically connected to pin 12 of the microcontroller U69.

[0026] Optionally, the operational amplifier U115 uses COS721TR. The first voltage divider unit includes a resistor R255 and a resistor R254, wherein one end of the resistor R255 is connected to pin 1 of the operational amplifier U115, and the other end is connected to one end of the resistor R254 and the ADC input end of the control module, and the other end of the resistor R254 is connected to GND.

[0027] As a preferred solution of the current sampling module, it also includes a capacitor C224, one end of the capacitor C224 is connected to the other end of the resistor R255, and the other end of the capacitor C224 is connected to GND. The capacitor C224 is used to form an RC filtering unit with the resistor R255.

[0028] like Figure 3 As shown, the voltage sampling module includes a second voltage divider unit, an isolated voltage sampling chip U113, and an operational amplifier U114 connected in sequence, the second voltage divider unit is connected to the positive and negative terminals of the welding machine output, the operational amplifier U114 is connected to the control module, the second voltage divider unit is used to convert the voltage output by the welding machine, the isolated voltage sampling chip U113 is used to convert the voltage signal converted by the second voltage divider unit into a group of differential signals, and the operational amplifier U114 is used to convert a group of differential signals into single-ended signals and then send them to the ADC input end of the control module. Optionally, the isolated voltage sampling chip U113 uses NSI1311-DSWVR, and the operational amplifier U114 uses COS721TR.

[0029] Specifically, the second voltage divider unit includes a resistor 252 and a resistor R253, one end of the resistor 252 is connected to the positive and negative terminals of the welding machine output through the connector CN10, the other end of the resistor 252 is connected to one end of the resistor R253 and the 2nd pin of the isolation voltage sampling chip U113, the other end of the resistor R253 is connected to AGND, the 1st pin of the isolation voltage sampling chip U113 is connected to A5V and one end of the capacitor C222, the other end of the capacitor C222 is connected to AGND, the 3rd and 4th pins of the isolation voltage sampling chip U113 are connected and connected to AGND, the 8th pin of the isolation voltage sampling chip U113 is connected to +5V, and the 5th pin of the isolation voltage sampling chip U113 is connected GND, pin 7 of the isolated voltage sampling chip U113 is connected to pin 3 of the operational amplifier U114 through resistor R247, pin 6 of the isolated voltage sampling chip U113 is connected to pin 4 of the operational amplifier U114 through resistor R248, resistor R250 is connected between pin 4 and pin 1 of the operational amplifier U114, pin 5 of the operational amplifier U114 is connected to +5V, pin 3 of the operational amplifier U114 is connected to GND through resistor R249, pin 2 of the operational amplifier U114 is connected to GND, and pin 1 of the operational amplifier U114 is used to connect to the ADC input of the control module, specifically connected to pin 11 of the microcontroller U69.

[0030] Preferably, pin 1 of the operational amplifier U114 is connected to one end of the resistor R251, the other end of the resistor R251 is connected to one end of the capacitor C223 and the ADC input end of the control module, the other end of the capacitor C223 is connected to GND, and the capacitor C223 and the resistor R251 form an RC filter unit.

[0031] Preferably, the other end of the resistor 252 is also connected to the cathode of the Zener diode D37, and the anode of the Zener diode D37 is connected to AGND.

[0032] like Figure 5 As shown, the communication module includes an RS485 isolation module U116, a protection unit, and a common mode filter unit connected in sequence. Pins 3 and 4 of the RS485 isolation module U116 are respectively connected to the 485_TX pin and the 485_RX pin of the microcontroller U69, pin 2 of the RS485 isolation module U116 is connected to GND, pin 1 of the RS485 isolation module U116 is connected to +5V, pin 10 of the RS485 isolation module U116 is connected to AGND, pins 9 and 8 of the RS485 isolation module U116 are connected to the protection unit, and the output end of the common mode filter unit is connected to the host computer through the host computer terminal, and the output end of the common mode filter unit is connected in parallel with a bus terminal resistor R264. Optionally, the RS485 isolation module U116 uses TD501D485H-A.

[0033] Specifically, the protection unit includes an electrostatic surge protection diode D38 and an electrostatic surge protection diode D39, the common mode filtering unit includes a capacitor C226, a common mode filter L13 and a common mode filter L14, the 9th pin of the RS485 isolation module U116 is connected to the cathode of the electrostatic surge protection diode D38, one end of the capacitor C226, and an input end of the common mode filter L13, the 8th pin of the RS485 isolation module U116 is connected to the cathode of the electrostatic surge protection diode D39, the other end of the capacitor C226, and the other input end of the common mode filter L13, the input end of the common mode filter L13 is connected to the input end of the common mode filter L14, the output end of the common mode filter L14 is connected to the host computer through the host computer terminal, the bus terminal resistor R264 is connected in parallel between the two ends of the output end of the common mode filter L14, and the positive pole of the electrostatic surge protection diode D38 and the positive pole of the electrostatic surge protection diode D39 are respectively connected to AGND.

[0034] Current sampling part: The current Hall sensor transmits the current signal to the operational amplifier U115, and then passes through the voltage divider and RC filtering unit composed of resistor R254, resistor R255, and capacitor C224, and enters the 12th pin (ADC_IN3) of the microcontroller U69.

[0035] Voltage sampling part: The 0-75V voltage of the welding machine is converted into 0-2V through the resistor divider circuit composed of resistors R252 and R253. The signal is converted into a set of differential signals through the isolated voltage sampling chip U113, and the operational amplifier U114 converts the differential signal into a single-ended signal, and then the RC filter unit composed of resistor R251 and capacitor C223 inputs the 11th pin (ADC_IN2) of the microcontroller U69.

[0036] RS485 bus part: The 485_TX and 485_RX signals of the microcontroller U69 are connected to the RS485 isolation module U116 and converted into isolated bus signals. The signals pass through the common-mode filtering circuit composed of capacitor C226, common-mode filter L13 and common-mode filter L14, and are transmitted to the host computer through the host computer bus terminal.

[0037] By applying the circuit in this example, the current and voltage parameters of old traditional welding equipment can be connected to the management and monitoring system through this circuit. At the same time, digital intelligent manufacturing is also promoted, which is convenient for better management of equipment and can also save a lot of money for purchasing new equipment.

[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application.

Claims

1. A welding machine digital sampling and conversion circuit, characterized in that: Including current sampling module, voltage sampling module, control module and communication module; The input end of the current sampling module is connected to the current Hall sensor provided at the welding machine, and the output end is connected to the control module. The current sampling module is used to amplify and divide the current signal of the current Hall sensor and then send it to the ADC input end of the control module; The voltage sampling module includes a second voltage dividing unit, an isolated voltage sampling chip U113, and an operational amplifier U114 which are connected in sequence. The second voltage dividing unit is connected to the positive and negative terminals of the welding machine output. The operational amplifier U114 is connected to the control module. The second voltage dividing unit is used to convert the voltage output by the welding machine. The isolated voltage sampling chip U113 is used to convert the voltage signal converted by the second voltage dividing unit into a group of differential signals. The operational amplifier U114 is used to convert a group of differential signals into single-ended signals and then send them to the ADC input end of the control module. The control module is connected to the communication module and is used to convert the signals transmitted by the current sampling module and the voltage sampling module obtained by the ADC input end into analog-to-digital signals and then upload them to the host computer through the communication module.

2. The welding machine digital sampling and conversion circuit according to claim 1 is characterized in that: The current sampling module includes an operational amplifier U115 and a first voltage divider unit connected in sequence. Pin 3 of the operational amplifier U115 is connected to the current Hall sensor at the welding machine through the connector CN11, pin 2 is connected to GND, pin 1 is connected to pin 5, pin 4 is connected to +5V and one end of the capacitor C225, and the other end of the capacitor C225 is connected to GND. The first voltage divider unit is connected to pin 1 of the operational amplifier U115 and the ADC input end of the control module.

3. The welding machine digital sampling conversion circuit according to claim 2 is characterized in that: The first voltage dividing unit includes a resistor R255 and a resistor R254. One end of the resistor R255 is connected to pin 1 of the operational amplifier U115, and the other end is connected to one end of the resistor R254 and the ADC input end of the control module. The other end of the resistor R254 is connected to GND.

4. The welding machine digital sampling conversion circuit according to claim 3 is characterized in that: The current sampling module further includes a capacitor C224, one end of the capacitor C224 is connected to the other end of the resistor R255, and the other end of the capacitor C224 is connected to GND. The capacitor C224 is used to form an RC filter unit with the resistor R255.

5. The welding machine digital sampling and conversion circuit according to claim 1 is characterized in that: The second voltage divider unit includes a resistor 252 and a resistor R253. One end of the resistor 252 is connected to the positive and negative terminals of the welding machine output through the connector CN10. The other end of the resistor 252 is connected to one end of the resistor R253 and the 2nd pin of the isolation voltage sampling chip U113. The other end of the resistor R253 is connected to AGND. The 1st pin of the isolation voltage sampling chip U113 is connected to A5V and one end of the capacitor C222. The other end of the capacitor C222 is connected to AGND. The 3rd and 4th pins of the isolation voltage sampling chip U113 are connected and connected to AGND. The 8th pin of the isolation voltage sampling chip U113 is connected to +5V. Pin 5 of 3 is connected to GND, pin 7 of the isolated voltage sampling chip U113 is connected to pin 3 of the operational amplifier U114 through resistor R247, pin 6 of the isolated voltage sampling chip U113 is connected to pin 4 of the operational amplifier U114 through resistor R248, resistor R250 is connected between pin 4 and pin 1 of the operational amplifier U114, pin 5 of the operational amplifier U114 is connected to +5V, pin 3 of the operational amplifier U114 is connected to GND through resistor R249, pin 2 of the operational amplifier U114 is connected to GND, and pin 1 of the operational amplifier U114 is used to connect to the ADC input of the control module.

6. The welding machine digital sampling and conversion circuit according to claim 5 is characterized in that: Pin 1 of the operational amplifier U114 is connected to one end of the resistor R251, the other end of the resistor R251 is connected to one end of the capacitor C223 and the ADC input end of the control module, the other end of the capacitor C223 is connected to GND, and the capacitor C223 and the resistor R251 form an RC filter unit.

7. The welding machine digital sampling and conversion circuit according to claim 5 is characterized in that: The other end of the resistor 252 is also connected to the cathode of the Zener diode D37, and the anode of the Zener diode D37 is connected to AGND.

8. The welding machine digital sampling and conversion circuit according to claim 1 is characterized in that: The control module includes a microcontroller U69, and the communication module includes an RS485 isolation module U116, a protection unit, and a common-mode filter unit which are connected in sequence. Pins 3 and 4 of the RS485 isolation module U116 are respectively connected to the 485_TX pin and the 485_RX pin of the microcontroller U69, pin 2 of the RS485 isolation module U116 is connected to GND, pin 1 of the RS485 isolation module U116 is connected to +5V, pin 10 of the RS485 isolation module U116 is connected to AGND, pins 9 and 8 of the RS485 isolation module U116 are connected to the protection unit, and the output end of the common-mode filter unit is connected to the host computer through the host computer terminal, and the output end of the common-mode filter unit is connected in parallel with a bus terminal resistor R264.

9. The welding machine digital sampling and conversion circuit according to claim 8, characterized in that: The protection unit includes an electrostatic surge protection diode D38 and an electrostatic surge protection diode D39, the common mode filtering unit includes a capacitor C226, a common mode filter L13 and a common mode filter L14, the 9th pin of the RS485 isolation module U116 is connected to the cathode of the electrostatic surge protection diode D38, one end of the capacitor C226, and an input end of the common mode filter L13, the 8th pin of the RS485 isolation module U116 is connected to the cathode of the electrostatic surge protection diode D39, the other end of the capacitor C226, and the other input end of the common mode filter L13, the input end of the common mode filter L13 is connected to the input end of the common mode filter L14, the output end of the common mode filter L14 is connected to the host computer through the host computer terminal, the bus terminal resistor R264 is connected in parallel between the two ends of the output end of the common mode filter L14, and the positive pole of the electrostatic surge protection diode D38 and the positive pole of the electrostatic surge protection diode D39 are respectively connected to AGND.

10. The welding machine digital sampling and conversion circuit according to claim 1, characterized in that: A power supply module is also included to provide +5V and +3.3V to the circuit.

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