CN213210770U

CN213210770U - Intelligent instrument debugger

Info

Publication number: CN213210770U
Application number: CN202022666291.1U
Authority: CN
Inventors: 崔家铭
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2021-05-14
Anticipated expiration: 2030-11-18

Abstract

The utility model provides an intelligent instrument debugger, which comprises a microcontroller module, a digital signal processing module and a digital/analog (D/A) module, wherein the microcontroller module receives signals from a keyboard module and a measuring module, converts the signals of the measuring module into digital signals and sends the digital signals to a liquid crystal display, or sends the digital signals to the D/A module and converts the digital signals into analog current output; the switching power supply module is used for providing a power supply for other modules of the debugger; the D/A conversion module is used for receiving a high-voltage power supply provided by the high-voltage output switch power supply module and a serial digital instruction value from the microcontroller, and outputting a current or voltage signal for instrument adjustment; the liquid crystal display module is used for displaying the display content sent by the microcontroller module; the keyboard module sets the current number required by the intelligent instrument or the percentage opening number of the intelligent instrument; and the measuring module is used for measuring a control signal which is sent to the intelligent instrument to be calibrated by the central control room in the process of calibrating the intelligent instrument, and the debugger has the characteristic of facilitating the calibration of the instrument.

Description

Intelligent instrument debugger

Technical Field

The utility model relates to a debugger technical field especially relates to an intelligent instrument debugger.

Background

In a process control system, such as a production system in the petrochemical industry, many types of instruments, such as positioners, electric actuators, secondary instruments, etc. used in various control valves, require control signals of 4-20 mA. In normal production, signals of the control instruments come from a Distributed Control System (DCS), and the signals are generally fixed at a certain value according to control requirements; however, in the process of maintaining and adjusting the instrument, the debugging signal needs to be randomly changed from 4-20mA, and the communication equipment and the central control room generally need to be used to request to continuously change the output value as the adjusting signal, which is very inconvenient.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve is: in order to overcome the deficiencies in the prior art, the utility model provides an intelligent instrument debugger.

The utility model provides a technical scheme that its technical problem will adopt is: an intelligent instrument debugger comprises a microcontroller module, a switching power supply module, a D/A conversion module, a liquid crystal display module, a keyboard module and a measurement module, wherein the microcontroller module is used for receiving signals from the keyboard module and the measurement module, converting analog signals of the measurement module into digital signals and sending the digital signals to the liquid crystal display module for display; a built-in SPI asynchronous serial module is utilized to send digital signals to a D/A module, and the digital signals are converted into required analog current to be output; the switching power supply module is used for providing a power supply for other modules of the debugger; the D/A conversion module is used for receiving a high-voltage power supply provided by the high-voltage output switch power supply module and a serial digital command value from the microcontroller U6, and outputting a current (0-24mA) and a voltage signal (0-5VDC) with certain magnitude for instrument calibration; the liquid crystal display module is used for displaying the display content sent by the microcontroller module; the keyboard module is used for setting a display mode, the number of currents required by the intelligent instrument or the equal percentage opening number of the intelligent instrument; and the measuring module is used for measuring a control signal which is sent to the intelligent instrument to be calibrated by the central control room in the intelligent instrument calibration process, measuring a direct current voltage less than 30VDC and a direct current less than 30mA, and avoiding the encumbrance and inconvenience of carrying the universal meter during the debugging.

Further, the microcontroller module specifically includes microcontroller U6 and external voltage signal detection circuit, wherein, microcontroller U6 adopts former Motorola semiconductor, later more name is S08QG8 of flying sieckel, this microcontroller U6(MCU, commonly called singlechip) instruction execution speed is fast, the low power consumption, the interference killing feature is strong, the operation is stable, be the high-end chip in the industrial control field, there is 8KFlash program memory space, there is the on-chip ADC converter, and abundant SCI, SPI, IIC interface, KBI keyboard interrupt module, and programmable, the operating frequency up to 20MHz, just in time be applicable to this intelligent instrument debugger. The external voltage signal detection circuit comprises a resistor R13, a variable resistor R14 and a diode D4, wherein the anode of the diode D4 is connected with a terminal J2, the cathode of the diode D4 is sequentially connected with the variable resistor R14 and the resistor R13 in series and then grounded, the sliding end of the variable resistor R14 is connected with the common end of the variable resistor R14 and the resistor R13, and the common end is connected with a pin 12 of the microcontroller and used for being connected into an A/D module in the microcontroller U6. Preferably, the diode D4 is IR 1407.

The power supply module is used for providing power supply for other modules of the debugger, and specifically comprises a power supply, a power supply switch module, a power supply detection module, a low-voltage switch power supply module and a high-voltage switch power supply module, wherein the power supply is controlled to be switched on and switched off through the power supply switch module; the power supply detection module is used for detecting whether the input power supply voltage is normal; the low-voltage switch power supply module is used for providing power supply voltage for other modules such as the microcontroller U6 and the like; the high-voltage switch power supply module is used for providing stable power supply voltage and current for the D/A module.

For realizing the functions of automatically starting up after inserting the signal wire and automatically shutting down after removing the signal wire, the power switch module comprises a socket and a plug, the socket is provided with a normally open contact, one end of the normally open contact is connected with a power supply, the other end of the normally open contact is connected with a subsequent circuit module, after the plug is inserted into the socket, the normally open contact is short-circuited, the power supply is switched on with the subsequent circuit, and the automatic starting up after inserting the plug and the automatic shutdown after pulling out the plug are realized.

The intelligent instrument debugger needs power supplies with two voltages and is uniformly powered by 1-3 sections of 5# or 7# batteries. The voltage from the battery is processed by two switching power supplies, one path of the voltage is used for providing power for the D/A module after being boosted to 16-24VDC adjustable output voltage, and the rest part of the voltage is converted into 3VDC stable voltage to provide power for a CPU, an LCD, a keyboard and the like.

The 3VDC low-voltage switching power supply module (3V switching power supply for short) specifically comprises a direct-current power supply chip U5, capacitors C10 and C11 and an inductor L2, wherein the direct-current power supply chip U5 uses a MAX1724 DC-DC chip, and is characterized in that the wide voltage input of 1.2V-5.5VDC is realized, an external resistor can be set to be 2.97 VDC-3.03 VDC and high-precision and high-stability output voltage of 400mA-600mA through pulse width modulation according to needs, the conversion efficiency can reach 90%, the utilization efficiency of a battery can be greatly improved, the service time after one-time replacement is prolonged, and the expenditure is saved. The capacitor C10 is connected between the power output end VDD and the ground for filtering the output end, the capacitor C11 is connected between the power input end VIN and the ground for filtering the input end, and two ends of the inductor L2 are respectively connected with a BATT pin and an LX pin of the MAX1724 for generating high-frequency oscillation inside the chip.

The 16-24VDC high-voltage switch power supply module (24V switch power supply for short) is realized by adopting a switch power supply U2, and the voltage of 0.9-4.5V supplied by the battery pack is increased to stable 16-24VDC adjustable output voltage and current output to provide power for the D/A module. The power supply module comprises an MOS tube U1, a switching power supply chip U2, a diode D1, an inductor L1, a variable resistor RK1, resistors R1, R2, R3 and R4, capacitors C1, C2, C3, C4 and C5, preferably, the MOS tube U1 is IR7401, the direct-current power supply chip U2 is an MAX668/669 switching power supply module chip, the input voltage is 1.8 VDC-28 VDC, and stable output of 3VDC-30VDC and the current can reach 0.5A can be output according to different external element configurations. Pin 1 of a direct-current power supply chip U2 is grounded after passing through a capacitor C4, pin 2 is grounded after passing through a resistor R4, pin 3 is grounded, pin 4 is grounded after passing through a capacitor C3, pin 5 is grounded after passing through a capacitor C5, pin 7 is connected with a resistor R1 in series and then is connected to pin 6, pin 8 outputs EXT signals, and pin 9 and pin 10 are grounded after passing through a capacitor C2 after being short-circuited; the pin 1, the pin 2, the pin 3 and the pin 4 of the MOS tube U1 are connected to the pin 6 of the DC power supply chip U2 after being short-circuited, and the pin 5, the pin 6, the pin 7 and the pin 8 are connected to the common end of the inductor L1 and the diode D1 after being short-circuited; one end of the inductor L1 is connected with an input power Vin, the other end of the inductor L1 is connected with the anode of the diode D1, and the cathode of the diode D1 outputs an AVDD power supply; the input power Vin is grounded through a capacitor C1; one path of the AVDD power supply is used as output, the other path of the AVDD power supply is grounded after sequentially passing through a variable resistor RK1, a resistor R2 and a resistor R3, and a common leading-out end of the resistor R2 and the resistor R3 is connected to a pin 5 of a direct-current power supply chip U2.

The D/A conversion module adopts 16-24VDC power supply from a U2 module (figure 5), receives a 16-bit serial digital command value from the microcontroller, outputs a 0-24mA current signal and a 14-24 VDC voltage signal, and is used for instrument calibration. The D/A conversion module mainly adopts a D/A conversion chip U4, preferably, the D/A conversion chip U4 can adopt an AD420, AD5410 or AD5420 chip of ANALOG DEVICES company, and a circuit when the AD420 is adopted further comprises adjustable resistors R5 and R6, resistors R7, R8 and R9 and capacitors C6, C7, C8, C13 and C14.

In order to cooperate with the intelligent instrument debugger, a segment type liquid crystal display is customized, and the segment type liquid crystal display has low-voltage alarm display, percentage output display, mA signal output display and a display window for comparing a programming value with an actual output signal. The whole liquid crystal display module is provided with a driving module, receives serial data instruction input, and the corresponding register receives a corresponding display instruction, so that the display precision can reach 0.0001 mA.

The keyboard module comprises four keys S1, S2, S3 and S4, wherein one end of each key is grounded after the four keys are connected in parallel, and the other end of each key is connected with four IO pin signal ends of the microcontroller U6 respectively and is used for setting modes such as input, output and display and related information. The operation is convenient, the service life of the keyboard is prolonged, the whole intelligent instrument display is more attractive, and the membrane switch is customized.

The utility model has the advantages that: the utility model provides an intelligent instrument debugger, DCS control signal can be disengaged in the instrument calibration process, the signal outputted by the debugger replaces the control signal of the central control room to calibrate and maintain the instrument; the debugger is portable handheld equipment, so that a signal output to a control instrument can be conveniently changed at any time and any place by using the debugger without a central control room signal, and the instrument can be more conveniently calibrated; in addition, the device can also be used for detecting other related signals, such as whether the control signal from the central control room is normal or not, so that the additional carrying of measuring instruments such as a multimeter and the like is avoided, and the use by a user is facilitated.

Drawings

The present invention will be further explained with reference to the drawings and examples.

Fig. 1 is the principle schematic diagram of the utility model discloses intelligent instrument debugger.

Fig. 2 is a circuit schematic of a microcontroller.

Fig. 3 is a circuit schematic of a power switch module.

Fig. 4 is a circuit schematic of a 3VDC low voltage switching power supply module.

Fig. 5 is a circuit schematic of a 16-24VDC high voltage switching power supply module.

Fig. 6 is a circuit schematic of the D/a conversion module.

Fig. 7 is a schematic view of a liquid crystal display module.

Fig. 8 is a circuit schematic of the keyboard module.

Fig. 9 is a schematic configuration diagram of a debugger panel.

Detailed Description

The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, and merely illustrates the basic structure of the present invention in a schematic manner, and therefore it shows only the constitution related to the present invention.

As shown in fig. 1, the utility model discloses an intelligent instrument debugger, including microcontroller module, switching power supply module, DA conversion module, liquid crystal display module, keyboard module and measuring module, wherein, switching power supply module includes power, switch module, power detection module, 3VDC low-voltage switch power supply module and 16-24VDC high-voltage switch power supply module. Each module is described in detail below.

As shown in fig. 2, the microcontroller module receives an instruction from the keyboard by using a built-in keyboard monitoring module and an interrupt function; the display content is sent to the liquid crystal display by utilizing the built-in SPI asynchronous serial module; the built-in SPI asynchronous serial module is used for sending digital signals to the D/A module, and the digital signals are converted into needed analog current to be output; and receiving the signal from the measuring module, converting the signal into a required digital signal by using a built-in A/D module, and sending the digital signal to a liquid crystal display for display. The intelligent instrument debugger specifically comprises a microcontroller U6, wherein the microcontroller U6 adopts an original Motorola semiconductor, is called as an MC9S08QG8 of the company of Feizuhu, Enzhipu, the instruction execution speed of the microcontroller U6(MCU, commonly called as a single chip microcomputer) is high, the power consumption is low, the anti-interference capability is high, the operation is stable, the microcontroller U6 is a high-end chip in the field of industrial control, an 8KFlash program storage space is provided, an on-chip ADC converter is provided, and abundant SCI, SPI, an IIC interface, a KBI keyboard interrupt module is provided, and the microcontroller U6 is programmable and has the operation frequency of 20MHz, and the intelligent instrument debugger is just suitable for the intelligent instrument debugger. The external voltage signal detection circuit is characterized in that signals are accessed from a J2 port, pass through a diode D2, pass through a resistor R13, a variable resistor R14 and a diode D4, a diode D4 anode connecting terminal J2, a cathode is sequentially connected in series with the variable resistor R14 and the resistor R13 and then is grounded, a sliding end of a variable resistor R14 is connected to a common end of the variable resistor R14 and the resistor R13, and the common end is connected with a pin 12 of the microcontroller and used for being accessed to an A/D module in the microcontroller U6. Preferably, the diode D4 is IR 1407. The resistor R14 is used to adjust the measurement accuracy.

As shown in fig. 3-5, the switching power supply module is used to provide power supply for other modules of the debugger, and is divided into two parts, one part is used to boost the battery voltage and convert the battery voltage into a power supply with adjustable voltage of 16-24VDC, as shown in fig. 5, for D/a conversion; some of them utilize a switching power supply module, which can convert it to a stable 3VDC for the rest of the modules such as the microcontroller even if the battery voltage is below 0.8V, as shown in fig. 4. The switching power supply module specifically comprises a power supply, a power supply switching module, a power supply detection module, a 3VDC low-voltage switching power supply module and a 16-24VDC high-voltage switching power supply module. In this embodiment, the power source is a battery.

As shown in fig. 3, in order to realize the functions of automatic power-on when a signal line is inserted and automatic power-off when the signal line is removed, the power switch module skillfully uses the characteristics of a normally open contact of a stereo socket and a short circuit after a stereo plug is inserted, and the power switch module is used as a switch for communicating the positive pole of the battery, namely the positive pole of the battery is communicated with the positive pole input end of the power supply in the circuit after the plug is inserted, so that the power supply is communicated. In fig. 3, the left diagram is a schematic diagram of a stereo plug not inserted, and the right diagram is a schematic diagram of a stereo plug inserted.

The intelligent instrument debugger needs power supplies with two voltages and is uniformly powered by 1-3 sections of 5# or 7# batteries. The voltage from the battery is processed by two switching power supplies, one path of the voltage is used for providing power for the D/A module after being boosted to 16-24VDC, and the rest part of the voltage is converted into stable voltage of 3VDC to provide power for a CPU, an LCD, a keyboard and the like. The power supply detection module is used for measuring external signal voltage, and particularly passes through an internal A/D module of the U6.

As shown in fig. 4, one switching power supply is a 3VDC low-voltage switching power supply module (referred to as 3V switching power supply for short), and specifically includes a DC power supply chip U5, capacitors C10 and C11, and an inductor L2, where the DC power supply chip U5 uses a MAX1724 DC-DC chip, and is characterized by a wide voltage input of 1.2V-5.5VDC, and an external resistor may be set to a high-precision and high-stability output voltage of 2.97 VDC-3.03 VDC and up to 400mA-600mA by pulse width modulation as required, and the conversion efficiency may reach 90%, which may greatly improve the utilization efficiency of the battery, prolong the service time after one replacement and save expenses. The capacitor C10 is connected between the power output end VDD and the ground for filtering the output end, the capacitor C11 is connected between the power input end VIN and the ground for filtering the input end, and two ends of the inductor L2 are respectively connected with a BATT pin and an LX pin of the MAX1724 for generating high-frequency oscillation inside the chip.

As shown in fig. 5, another switching power supply is a 16-24VDC high voltage switching power supply module (abbreviated as 24V switching power supply), which provides stable power supply voltage and current for the D/a module, and specifically includes a MOS transistor U1, a dc power supply chip U2, a diode D1, an inductor L1, a variable resistor RK1, resistors R1, R2, R3 and R4, capacitors C1, C2, C3, C4 and C5, preferably, the MOS transistor U1 is an IR7401, the dc power supply chip U2 is a MAX668/669 power supply module chip, the input voltage is 1.8 VDC-28 VDC, and a stable output of 3VDC-30VDC and current up to 0.5A can be output according to different external element configurations. Referring to fig. 5, a pin 1 of a dc power supply chip U2 is grounded after passing through a capacitor C4, a pin 2 is grounded after passing through a resistor R4, a pin 3 is grounded, a pin 4 is grounded after passing through a capacitor C3, a pin 5 is grounded after passing through a capacitor C5, a pin 7 is connected in series with a resistor R1 and then connected to a pin 6, a pin 8 outputs an EXT signal, and a pin 9 and a pin 10 are grounded after being shorted and passing through a capacitor C2; the pin 1, the pin 2, the pin 3 and the pin 4 of the MOS tube U1 are connected to the pin 6 of the DC power supply chip U2 after being short-circuited, and the pin 5, the pin 6, the pin 7 and the pin 8 are connected to the common end of the inductor L1 and the diode D1 after being short-circuited; one end of the inductor L1 is connected with an input power Vin, the other end of the inductor L1 is connected with the anode of the diode D1, and the cathode of the diode D1 outputs an AVDD power supply; the input power Vin is grounded through a capacitor C1; one path of the AVDD power supply is used as output, the other path of the AVDD power supply is grounded after sequentially passing through a variable resistor RK1, a resistor R2 and a resistor R3, and a common leading-out end of the resistor R2 and the resistor R3 is connected to a pin 5 of a direct-current power supply chip U2.

As shown in fig. 5, the D/a conversion module is powered by 16-24VDC from a dc power supply chip U2, receives a 16-bit serial digital command value from the microcontroller, and outputs an analog current signal of 0-24mA and a voltage signal of 16-24VDC for calibration of the smart meter. The D/A conversion module mainly adopts a D/A conversion chip U4, preferably, the D/A conversion chip U4 can adopt an AD420, AD5410 or AD5420 chip of ANALOG DEVICES company, and a circuit when the AD420 is adopted further comprises adjustable resistors R5 and R6, resistors R7, R8 and R9 and capacitors C6, C7, C8, C13 and C14.

A liquid crystal display module: 5-bit pen segment type digital display, 3-bit pen segment type digital display, and low voltage, error, percent and mA state display. The 5-bit pen-segment type digital part is used for displaying the mA number or the opening percentage number required to be output; displaying the value measured by the measuring module; a "PRG" section, a 3-bit pen-segment numerical display, which increases or decreases the change value (step) of the output value every time a key is pressed; displaying the power supply detection condition and prompting a user to replace the battery as soon as possible; the D/A conversion module receives a 16-24VDC power supply provided by the high-voltage output switching power supply module and a 16-bit serial digital command value from the microcontroller, outputs output signals of 0-24mA and 14-24 VDC, and is used for instrument calibration. The D/a conversion module mainly uses a D/a conversion chip U4, preferably, the D/a conversion chip U4 may use AD420, AD5410 or AD5420 chips of ANALOG DEVICES, and the circuit when using AD420 further includes adjustable resistors R5 and R6, resistors R7, R8 and R9, and capacitors C6, C7, C8, C13 and C14, and the specific connection relationship is as shown in fig. 6.

In order to cooperate with the intelligent instrument debugger, a segment type liquid crystal display is customized, and the intelligent instrument debugger has low-voltage alarm, percentage output display, mA signal output display modes and a display window for comparing a programming value with an actual output signal. The whole liquid crystal display module is provided with a driving module, receives input of an SPI asynchronous serial data instruction, a corresponding register receives a corresponding display instruction, and the liquid crystal display module with the display precision reaching 0.0001mA is shown in fig. 7.

As shown in fig. 8 and 9, the keyboard module sets the output mode to a mA current signal mode, or a% mode by meter opening; setting the mA current number or the opening percentage number required to be output by each mode; receiving and displaying a measured value sent by a microcontroller signal; setting the number of mA or opening% change (step distance, PRG part) for each press of key; the four-key keyboard specifically comprises four keys S1, S2, S3 and S4, wherein one end of each key is grounded, and the other end of each key is connected with signal ends of four IO pins (pin 13-pin 16) of a microcontroller U6 respectively and used for inputting four-bit keyboard information. In order to facilitate the operation, prolong the service life of the keyboard and make the whole intelligent instrument display more beautiful, a membrane switch is customized as shown in fig. 9.

The measuring module is similar to a universal meter and is used for measuring a control signal which is sent to the intelligent instrument needing to be calibrated by a central control room in the calibration process of the intelligent instrument, measuring a direct current which is less than 30VDC (direct current) voltage and less than 30mA, and avoiding the encumbrance and inconvenience of carrying the universal meter during debugging.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. An intelligent instrument debugger, characterized in that: comprises that

The microcontroller module is used for receiving signals from the keyboard module and the measuring module, converting analog signals of the measuring module into digital signals and sending the digital signals to the liquid crystal display module for display; a built-in SPI asynchronous serial module is utilized to send digital signals to a D/A module, and the digital signals are converted into required analog current to be output;

the switching power supply module is used for providing a power supply for other modules of the debugger;

the D/A conversion module is used for receiving a high-voltage power supply provided by the high-voltage output switch power supply module and a serial digital instruction value from the microcontroller U6, and outputting a current or voltage signal with a certain magnitude for instrument calibration;

the liquid crystal display module is used for displaying the display content sent by the microcontroller module;

the keyboard module is used for setting a display mode, the number of currents required by the intelligent instrument or the equal percentage opening number of the intelligent instrument;

and the measuring module is used for measuring a control signal which is sent to the intelligent instrument to be calibrated by the central control room in the process of calibrating the intelligent instrument.

2. The smart meter debugger of claim 1, wherein: the microcontroller module comprises a microcontroller U6 and an external voltage signal detection circuit, wherein the microcontroller U6 adopts an MC9S08QG8 chip; the external voltage signal detection circuit comprises a resistor R13, a variable resistor R14 and a diode D4, wherein the anode of the diode D4 is connected with a terminal J2, the cathode of the diode D4 is connected with the variable resistor R14 and the resistor R13 in series in sequence and then grounded, the sliding end of the variable resistor R14 is connected with the common end of the variable resistor R14 and the resistor R13, and the common end is connected with a pin 12 of a microcontroller U6.

3. The smart meter debugger of claim 1, wherein: the switch power supply module comprises a power supply, a power switch module, a power detection module, a low-voltage switch power supply module and a high-voltage switch power supply module, wherein the power supply is controlled to be switched on and switched off through the power switch module, the power supply is divided into three paths after being input, the three paths are used as the input of the power detection module, the other paths are used as the input of the low-voltage switch power supply module, and the third path is used as the input of the high-voltage switch power supply module.

4. The smart meter debugger of claim 3, wherein: the power switch module comprises a socket and a plug, the socket is provided with a normally open contact, one end of the normally open contact is connected with a power supply, the other end of the normally open contact is connected with the subsequent circuit module, and after the plug is inserted into the socket, the normally open contact is short-circuited to realize the connection of the power supply and the subsequent circuit.

5. The smart meter debugger of claim 3, wherein: the low-voltage switching power supply module comprises a direct-current power supply chip U5, capacitors C10 and C11 and an inductor L2, wherein the direct-current power supply chip U5 adopts MAX1724, the capacitor C10 is connected between a power output end VDD and the ground and used for filtering of the output end, the capacitor C11 is connected between a power input end VIN and the ground and used for filtering of the input end, and two ends of the inductor L2 are respectively connected with a BATT pin and an LX pin of the MAX1724 and used for generating high-frequency oscillation inside the chip.

6. The smart meter debugger of claim 3, wherein: the high-voltage switching power supply module comprises an MOS tube U1, a direct-current power supply chip U2, a diode D1, an inductor L1, a variable resistor RK1, resistors R1, R2, R3 and R4, capacitors C1, C2, C3, C4 and C5, wherein the direct-current power supply chip U2 is a chip with the model of MAX669, a pin 1 of the chip is grounded through a capacitor C4, a pin 2 is grounded through a resistor R4, a pin 3 is grounded, a pin 4 is grounded through a capacitor C3, a pin 5 is grounded through a capacitor C5, a pin 7 is connected to a pin 6 after being connected with a resistor R1 in series, a pin 8 outputs an EXT signal, and a pin 9 and a pin 10 are grounded through a capacitor C2 after being short-circuited; the MOS tube U1 adopts IR7401, and is connected to a pin 6 of a DC power supply chip U2 after a pin 1, a pin 2, a pin 3 and a pin 4 are short-circuited, and is connected to a common end of an inductor L1 and a diode D1 after a pin 5, a pin 6, a pin 7 and a pin 8 are short-circuited; one end of the inductor L1 is connected with an input power Vin, the other end of the inductor L1 is connected with the anode of the diode D1, and the cathode of the diode D1 outputs an AVDD power supply; the input power Vin is grounded through a capacitor C1; one path of the AVDD power supply is used as output, the other path of the AVDD power supply is grounded after sequentially passing through a variable resistor RK1, a resistor R2 and a resistor R3, and a common leading-out end of the resistor R2 and the resistor R3 is connected to a pin 5 of a direct-current power supply chip U2.

7. The smart meter debugger of claim 1, wherein: the D/A conversion module comprises a D/A conversion chip U4, and the D/A conversion chip U4 adopts an AD420, an AD5410 or an AD5420 chip.

8. The smart meter debugger of claim 1, wherein: the liquid crystal display module adopts a pen-segment liquid crystal display and comprises low-voltage alarm display, percentage output display, mA signal output display and comparison display of a programming value and an actual output signal.

9. The smart meter debugger of claim 1, wherein: the keyboard module comprises four keys S1, S2, S3 and S4, wherein one end of each key is grounded after the four keys are connected in parallel, and the other end of each key is connected with four IO signal ends of the microcontroller U6.