CN104214082B - The controller of a kind of machine based on DSP load intelligent pump origin system - Google Patents

Abstract

The invention provides a controller of a DSP-based airborne intelligent pump source system, which includes an intelligent pump control board and a signal conditioning board. The intelligent pump control board includes DSP chip and its minimum circuit, AD sampling circuit, CAN communication module, DA output and voltage-to-current circuit. The signal conditioning board supplies power to the intelligent pump control board and sensors, and regulates the collected analog signals. The DSP chip communicates with the host computer through the CAN communication module, receives control commands, aircraft status parameters and work cycle task profiles from the host computer, determines the working mode of the hydraulic pump from the mode switching table, calculates and outputs the digital voltage that controls the action of the electro-hydraulic servo valve Signal to control the swash plate inclination angle of the hydraulic pump in real time, and control the outlet pressure or outlet flow of the hydraulic pump by changing the displacement of the hydraulic pump. The invention can change the control target according to the actual working conditions, effectively reduce the reactive power, control the heating of the hydraulic system, and reduce the overall weight of the airborne hydraulic system.

Description

A DSP-based controller for airborne intelligent pump source system

technical field

The invention belongs to the technical field of hydraulic pump control and state monitoring, and in particular relates to a controller of an airborne intelligent pump source system based on DSP (Digital Signal Processor, digital signal processor).

Background technique

The on-board hydraulic system of civil aircraft refers to the system on the aircraft that uses oil as the working medium and relies on hydraulically driven actuators to complete specific manipulation actions. As one of the secondary energy sources of the aircraft, the onboard hydraulic system mainly provides energy for the functions of the aircraft's main control system, auxiliary control system, auxiliary adjustment of engine-related components, speed brake retraction, landing gear retraction, wheel brakes, and ground turning. , its performance and reliability play a decisive role in ensuring the safe flight of the aircraft, the realization of the design performance and the survival guarantee of the pilot.

With the increase of civil aircraft's demand for small weight and large payload, the overall design of the aircraft requires that the onboard hydraulic system should not only be light in weight and small in size, but also high in power and high in reliability, so that the airborne The hydraulic system develops in the direction of high pressure and high power. At the same time, high voltage and high power increase the heating power and temperature rise, making it more difficult for the system to dissipate heat, making the system very bloated, and instead increasing the weight of the aircraft.

For the onboard hydraulic system of modern civil aircraft, the most ideal form of pump source is constant pressure source. Currently, constant pressure variable pumps are widely used in civil aircraft. However, since the working pressure of the constant pressure source is designed according to the maximum operating conditions, and in the typical flight profile of the aircraft, the flight time where the hydraulic system needs to use high pressure accounts for less than 10% of the total flight time, and the rest exceeds 90%. Only low pressure is needed to meet flight requirements during the time period. The efficiency of the onboard hydraulic system is relatively low when using a constant pressure source, and a large amount of reactive power is an important reason for the increase in the heating power of the onboard hydraulic system. one. Therefore, in order to effectively reduce the heating power of the hydraulic system and meet the requirements of various situations, it is necessary to actively control the swash plate plunger hydraulic pump, and achieve continuous adjustment of pressure or flow within a certain range to reduce generation of reactive power.

Contents of the invention

The purpose of the present invention is to provide a constant pressure variable pump controller, which can control the inclination angle of the swash plate in real time, and then control the displacement of the pump. By controlling the change of displacement, the controller can effectively control the pressure or flow of the pump, provide reasonable pressure or flow under different working conditions, reduce reactive power, and lower system temperature. At the same time, the controller can also monitor the operating status of the pump to ensure safe operation.

The DSP-based airborne intelligent pump source system controller provided by the present invention includes an intelligent pump control board and a signal conditioning board. The intelligent pump control board includes DSP chip and its minimum circuit, AD sampling circuit, CAN communication module, DA output and voltage-to-current circuit.

The signal conditioning board adjusts the analog signal input to the AD sampling circuit, and at the same time supplies power to the intelligent pump control board and sensors for measuring the pressure, temperature and displacement of the hydraulic pump. The pressure includes the outlet pressure and oil return pressure of the hydraulic pump, and the temperature includes the outlet temperature, oil return port temperature and shell temperature of the hydraulic pump.

The AD sampling circuit is used to collect the pressure, temperature and displacement of the follower piston of the hydraulic pump, and convert the analog signal into a digital signal and send it to the DSP chip.

Described DSP chip communicates with upper computer by CAN communication module, is used for completing: (1) the pressure, temperature and flow of hydraulic pump are uploaded to upper computer; Described hydraulic pump flow refers to the outlet flow of hydraulic pump, according to The displacement of the follower piston is calculated; (2) Receive the aircraft state parameters and the task profile of the work cycle from the host computer, determine the working mode of the hydraulic pump from the mode switching table according to the task profile of the work cycle, and calculate the output to control the action of the electro-hydraulic servo valve The digital voltage signal is used to control the inclination angle of the swash plate of the hydraulic pump in real time, and to control the outlet pressure or outlet flow of the hydraulic pump by changing the displacement of the hydraulic pump. The task profile of the working cycle includes pressure and flow parameters required by all actuators under the current working conditions. The mode switching table is pre-stored in the DSP chip, and is a table for judging the working mode of the hydraulic pump according to the values of the pressure and flow required by the actuator, the flight height and the flight speed; three types are set in the mode switching table. Working modes of the hydraulic pump: constant pressure mode, constant flow mode and load sensing mode.

The DA output and the voltage-to-current circuit include a DA output chip and a voltage-to-current circuit, the DA output chip converts the digital voltage signal output by the DSP chip into an analog voltage signal, and the voltage-to-current circuit converts the analog voltage signal to ±40mA The current signal is sent to the intelligent pump source system to control the action of the electro-hydraulic servo valve.

The DSP-based airborne intelligent pump source system controller provided by the present invention adopts a dual-redundancy design and includes two intelligent pump control boards. The AD sampling circuit and DA output chip in each smart pump control board adopt a dual-redundancy design, each with two chips. The signal conditioning channels on the signal conditioning board are also designed with double redundancy, including double the number of signal conditioning channels. The present invention collects 6 analog signals, so there are 12 signal conditioning channels on the signal conditioning board.

The advantages and positive effects of the controller of the airborne intelligent pump source system of the present invention are:

(1) The controller of the present invention can change the control target according to the actual working conditions, effectively reduce the reactive power under the premise of meeting the requirements of the hydraulic system, thereby controlling the heating of the hydraulic system, and then reducing the overall weight of the onboard hydraulic system;

(2) The controller of the present invention adopts DSP as the core embedded system, which is small in size and light in weight compared with the industrial computer, and is suitable for airborne conditions. Compared with the single-chip microcomputer, the DSP can realize a comparatively complicated control algorithm. Rich settings, convenient performance expansion, and more versatility and practicability;

(3) The controller of the present invention adopts a double-redundancy design. One controller includes two control boards, which are redundant backups for each other. Each control board has the ability to control two hydraulic pumps at the same time, which improves the reliability of the system. Sex, to meet the conditions of airborne equipment.

Description of drawings

Figure 1 is a schematic diagram of a traditional constant pressure variable pump;

Fig. 2 is a pressure-flow curve diagram of a traditional constant pressure variable pump;

Figure 3 is a structural diagram of the intelligent pump source experimental system;

Fig. 4 is a structural diagram of the intelligent pump source system controller;

Figure 5 is the voltage-to-current circuit of the control board of the intelligent pump source system controller.

detailed description

The intelligent pump controller and control method of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, it is a structure diagram of a traditional constant pressure variable pump. The variable mechanism of the traditional constant pressure variable pump consists of a pressure compensation valve, a follower piston and a return spring. The pressure compensation valve senses the outlet pressure of the pump, and completes the mechanical feedback control by comparing the outlet pressure with the set pressure, controls the movement of the follower piston, and then changes the inclination of the swash plate.

Figure 2 is the pressure-flow curve of a traditional constant pressure variable pump. The Q _s -P _s curve in the figure is the output of the constant pressure variable pump, and the Q _L -P _L is the change curve of the load. The shaded part in the figure represents the constant pressure variable The reactive power produced by the pump. It can be intuitively seen that the hydraulic pump does not follow the load very well. Under most load conditions, the hydraulic pump generates a large amount of reactive power, which is dissipated in the form of heat through the relief valve, thereby increasing the onboard hydraulic system. The thermal power requires additional heat dissipation equipment, resulting in an increase in overall weight.

In order to reduce the reactive power, the output of the hydraulic pump needs to be adjusted in real time according to the load condition. The present invention adopts the pump source system as shown in FIG. 3 . As shown in Fig. 3, the two smart pump source systems are equipped with the smart pump controller of the present invention, and the smart pump controller obtains the status information of the smart pump through the sensor, and controls the variable mechanism of the smart pump. The intelligent pump controller receives the analog signal from the sensor through the AD/DA (analog-digital/digital-analog) interface and converts it into a digital signal, converts the calculated digital control signal into an analog signal and sends it to the electro-hydraulic servo valve to control the intelligent pump variable body work. The control board communicates with the upper computer through the CAN (ControllerAreaNetwork, Controller Area Network) bus, and transfers the collected pump outlet pressure, pump return oil pressure, pump outlet temperature, pump casing temperature, pump return oil temperature and The six kinds of data of the displacement of the moving piston are uploaded to the host computer, where data display, status monitoring and parameter setting are performed, and control instructions from the host computer are received at the same time.

The controller of the intelligent pump source system changes the displacement of the hydraulic pump by controlling the inclination angle of the hydraulic pump swash plate, and through the analysis of the structure of the hydraulic pump, it can be known that the inclination angle of the swash plate needs to be controlled by controlling the position of the follower piston. Therefore, this program uses an electro-hydraulic servo valve to control the movement of the follower piston. As a preference, the electro-hydraulic servo valve uses the G701 series nozzle flapper valve of MOOG Company, and the rated control current is ±40mA.

Based on the structure and functional requirements of the intelligent pump source system, the present invention proposes a structural diagram of a DSP-based airborne intelligent pump source system controller as shown in FIG. 4 . The intelligent pump source system controller of the present invention includes two parts: an intelligent pump control board and a signal conditioning board, and the signal conditioning board is also used as a power supply board to supply power to the intelligent pump control board and sensors.

The intelligent pump control board includes DSP chip and its minimum circuit, AD sampling circuit, CAN communication module, DA output and voltage-to-current circuit.

In the embodiment of the present invention, the DSP chip uses the TMS320F28335 chip of Texas Instruments, the AD sampling circuit adopts the AD7606 analog-to-digital conversion chip, the CAN communication module adopts the CAN transceiver of the SN65HVD235 model, and in the DA output and the voltage-to-current circuit, the AD5791 digital The analog conversion chip realizes the DA output function. When designing, the AD sampling circuit, DA output and voltage-to-current circuit all adopt a double-redundancy design, which meets the reliability requirements.

The AD sampling circuit is used to collect the pressure, temperature and displacement of the follower piston of the hydraulic pump, and convert the analog signal into a digital signal and send it to the DSP chip. The collected pressure signal of the hydraulic pump refers to the outlet pressure and oil return pressure of the hydraulic pump measured by the pressure sensor; the temperature signal refers to the outlet temperature, oil return port temperature and casing temperature of the hydraulic pump measured by the temperature sensor; The displacement of the piston is used to calculate the outlet flow of the hydraulic pump, which is obtained by further calculation according to the displacement of the follower piston measured by the displacement sensor.

DA output and voltage-to-current circuit, including DA output chip and voltage-to-current circuit. The DA output chip converts the digital voltage signal output by the DSP chip into an analog voltage signal, and the power-to-current circuit converts the analog voltage signal into a ±40mA current signal. And transmit the current signal to the intelligent pump source system to control the action of the electro-hydraulic servo valve.

The DSP chip communicates with the upper computer through the CAN communication module, and the control program based on the PID algorithm is encapsulated in the DSP chip. The functions realized by the DSP chip include: (1) upload the pressure, temperature and flow of the hydraulic pump to the host computer; the flow of the hydraulic pump refers to the outlet flow of the hydraulic pump, which is calculated according to the displacement of the servo piston; The inclination angle of the swash plate of the pump outputs a digital voltage signal to control the action of the electro-hydraulic servo valve, and controls the output pressure or output flow of the hydraulic pump by changing the displacement of the hydraulic pump.

The DSP chip receives control commands from the host computer, mainly including commands to control the start and stop of the controller. The DSP chip receives the current engine speed, atmospheric parameters, aircraft state parameters, actuation system state parameters and duty cycle task profiles from the host computer. Atmospheric parameters mainly include external air pressure and air temperature. Aircraft state parameters mainly include flight altitude, flight speed, Mach number and attitude angle. The state parameters of the actuation system include the displacement of each actuator and the pressure of the two chambers. The duty cycle task profile includes the pressure and flow parameters required by all actuators under the current working conditions calculated by the host computer. According to the task profile of the working cycle, the DSP chip determines the working mode of the hydraulic pump from the mode switching table, calculates the inclination angle of the swash plate of the hydraulic pump, and outputs a digital voltage signal to control the action of the electro-hydraulic servo valve. The mode switching table is pre-generated and stored in the DSP chip. It is a table for judging the working mode of the hydraulic pump according to the values of the four parameters required by the actuator, the pressure and flow, the flight altitude and the flight speed.

Three working modes of the hydraulic pump are set in the mode switching table:

(1) In constant pressure mode, the reference input is the pressure required by the actuator, and the feedback signal is the outlet pressure of the hydraulic pump;

(2) Constant flow mode, the reference input is the flow required by the actuator, and the feedback signal is the outlet flow of the hydraulic pump;

(3) Load-sensing mode, that is, the outlet pressure of the hydraulic pump follows the demand pressure of the load, the reference input is the sum of the load pressure and the pressure drop of the electro-hydraulic servo valve, and the feedback signal is the outlet pressure of the hydraulic pump.

The DSP chip calculates and outputs a digital voltage signal to control the action of the electro-hydraulic servo valve according to the reference input and feedback signal, so as to change the displacement of the hydraulic pump.

The DSP chip of the intelligent pump control board in the embodiment of the present invention adopts the chip of model TMS320F28335, and this chip supports floating-point calculation, and can meet the calculation speed requirement of real-time control. At the same time, the F28335 integrates rich peripherals on the chip, which provides convenient conditions for the communication and control of the system. In order to meet the expansibility of the future program, the present invention also expands the FLASH chip of 4Mb of model SST39VF and the SRAM chip of 2Mb of CY7C1011CV33 for DSP, and the FLASH chip is controlled by XINTF6 of DSP, and the SRAM chip is controlled by XINTF7 of DSP. In practical application, the intelligent pump control board communicates with the flight control computer through the flight control bus 1553B. The present invention uses the BU61580 protocol chip to complete the communication protocol and controls it through the XINTF1 of the F28335. During system debugging, CAN bus is used to communicate with the laptop computer as the host computer. F28335 has its own ECAN module, which supports a maximum transmission rate of 1Mbps, and has 32 individually configurable mailboxes, which provide great convenience for the realization of communication. When using the CAN bus, only need to configure a CAN transceiver SN65HVD235 to achieve communication. As shown in Figure 4, the minimum circuit of the DSP chip also includes a chip power supply module, a clock circuit and an emulator interface circuit. The chip power supply module is used to convert the voltage transmitted by the signal conditioning board into a working voltage suitable for the DSP chip to supply power for the DSP chip. The function of the clock circuit is to provide a stable clock source for the DSP chip. The function of the interface circuit of the emulator is to burn and write the program when debugging the program in the DSP chip. The control program in the DSP chip also realizes the control of the external analog-to-digital conversion chip AD7606.

In order to meet the redundancy configuration requirements, each control board has two AD7606 analog-to-digital conversion chips and two AD5791 digital-to-analog conversion chips. AD7606 is an 8-channel 16-bit chip, and each AD7606 collects 6 sensor signals of an intelligent pump. AD5791 is a single-channel 20-bit chip, and each AD5791 controls an electro-hydraulic servo valve of a smart pump. The AD7606 uses a parallel output with a range of ±10V. The output ends of two slices of AD7606 are connected with 115- 136 ports of F28335. F28335 completes the signal acquisition of different pumps by controlling the chip selection signal of AD7606. The AD7606 has an input buffer with 1MΩ analog input impedance and a second-order anti-aliasing analog filter, which can greatly simplify the front-end analog signal conditioning circuit. AD5791 completes data transmission through SPI bus, and the present invention uses GPIO port of F28335 to simulate SPI timing to complete the control of AD5791.

The voltage output by AD5791 is converted into a ±40mA current signal through the voltage-to-current circuit in Figure 5, and then controls the electro-hydraulic servo valve. In the voltage-to-current circuit, the first stage uses AD622 as a voltage follower to regulate the voltage output by AD5791. After conditioning, the voltage signal is converted into a ±40mA current signal through a current negative feedback amplifier circuit composed of LH0041. The input voltage VOUT ^* has the following relationship with the output current I:

$\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; Rs.</span>}\mathrm{<span\; class="notranslate">\; 8</span>}}{\mathrm{<span\; class="notranslate">\; Rs.</span>}\mathrm{<span\; class="notranslate">\; 7</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; VOUT</span>}}^{<span\; class="notranslate">\; *</span>}}{\mathrm{<span\; class="notranslate">\; Rs.</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; Rs.</span>}\mathrm{<span\; class="notranslate">\; 5</span>}}}{\mathrm{<span\; class="notranslate">\; Rs.</span>}\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; )</span>$

Among them, U _Rs5 represents the zeroing voltage, its value can be changed by adjusting the potentiometer Rs6, and its function is to adjust the zero bias of the circuit. The amplification gain can be changed by adjusting the size of the potentiometer Rs8, and the output of the circuit can be adjusted to ±40mA by adjusting the gain. Resistor Rs1 is connected in series between AD622 output terminal and LH0041 negative input terminal, resistor Rs5 is connected in series between potentiometer Rs6 input terminal and LH0041 negative input terminal, resistor Rs7 is connected in series between analog ground and LH0041 output terminal, resistor Rs8 is connected in series between the negative input terminal of LH0041 and the output terminal of LH0041. In Figure 5, the current signal after passing through the DA output and the voltage-to-current circuit physically passes through the signal conditioning board, but no signal conditioning is required.

The function of the signal conditioning board is to condition the analog signal input to the AD sampling circuit, and at the same time supply power to the intelligent pump control board and the sensor. The signal conditioning board regulates the hydraulic pump outlet pressure signal, oil return pressure signal, temperature signal and linear displacement sensor signal. Due to the redundancy backup involved, there are 12 signal conditioning channels on one conditioning board. Due to the convenience brought by AD7606 to the design of the conditioning circuit, each signal conditioning channel can use a voltage follower composed of AD622. For the temperature sensor and LVDT, since the output of the sensor is 4-20mA, a 500Ω precision sampling resistor is designed at the front end of the voltage follower to convert the signal into a voltage signal of 2-10V. At the same time, the signal conditioning board, as the motherboard of the controller, also needs to supply power to the control board and sensors. Since the voltage of the aviation DC power supply is 28V, the signal conditioning board needs to convert 28V into three voltages of ±15V and +5V for use by various chips and sensors.

The controller of the airborne intelligent pump source system of the present invention can control the pump source system to work in a constant pressure, constant flow or load sensitive mode. The constant pressure mode is basically the same as the traditional constant pressure variable pump, and the pressure-flow characteristic curve is also consistent. The constant flow mode is mainly used in the conditions that require large flow or constant speed. The load sensing mode is used when the aircraft is cruising, and its characteristic is that it can change with the change of the load and maintain a pressure difference to ensure the normal operation of the servo valve of the aircraft actuation system. The switching of the working mode is completed by the controller after analyzing the atmospheric and aircraft status data transmitted from the flight control computer (host computer) and comparing it with the mode switching table stored in the controller. The controller adopts PID algorithm when calculating the control signal, and uses different PID parameters according to the different modes.

Through simulation and experimental analysis, the present invention can stably control the inclination angle of the swash plate of the hydraulic pump, thereby accomplishing a series of control objectives and suppressing the reactive power of the hydraulic pump.

Claims (4)

1. the controller of the load intelligent pump origin system of the machine based on DSP, it is characterised in that, intelligent pump origin system controller obtains the status information of intelligent pump by sensor, the variable mechanism of control intelligent pump; Intelligent pump origin system controller comprises intelligent pump switchboard and signal regulating panel; Wherein, intelligent pump switchboard comprises dsp chip and minimum circuit thereof, AD sample circuit, CAN communication module and DA and exports and Voltage-current conversion circuit;

Intelligent pump origin system controller changes hydraulic pressure pump duty by hydraulic control pump swashplate angle, and by analyzing the structure of hydro-pump it will be seen that need the position by controlling piston follower could control swashplate angle;

The simulating signal that described signal regulating panel is input AD sample circuit is nursed one's health, and powers to intelligent pump switchboard and for measuring the sensor of the pressure of hydro-pump, temperature and piston follower displacement simultaneously;

Described AD sample circuit is for gathering the displacement of the pressure of hydro-pump, temperature and piston follower, and simulating signal is converted to numerary signal and sends dsp chip to;

Described dsp chip passes through CAN communication module and upper machine communication, for completing: the pressure of hydro-pump, temperature and flow are uploaded to upper computer by (1); Described hydraulic pump flow refers to the rate of discharge of hydro-pump, calculates according to the displacement of piston follower; (2) aircraft state parameter and work period task section is received from upper computer, from pattern switching table, the operating mode of hydro-pump is determined according to work period task section, calculate the digital voltage signal exporting control electro-hydraulic servo valve events, with the swashplate angle of real-time hydraulic control pump, by changing displacement control hydraulic pump outlet pressure or the rate of discharge of hydro-pump; The pressure versus flow parameter of described work period task section all actuator needs under comprising current working; Described pattern switching table is stored in advance in dsp chip, is the form that pressure versus flow, flight height and the numerical value of flight velocity four kinds of parameters needed according to actuator judges hydraulic pump works pattern; Pattern switching table arranges the operating mode of three kinds of hydro-pumps: constant pressure pattern, permanent flow rate mode and load-sensitive pattern;

Described DA exports and Voltage-current conversion circuit, comprise DA pio chip and Voltage-current conversion circuit, the digital voltage signal that dsp chip exports is converted to analog voltage signal by DA pio chip, analog voltage signal is converted to �� 40mA electric current signal by Voltage-current conversion circuit, and send electric current signal to intelligent pump origin system, control electro-hydraulic servo valve events;

The model of described dsp chip is that TMS320F28335, F28335 carry ECAN module, and the transfer rate of the highest support 1Mbps, has 32 mailboxes that can configure separately; AD sample circuit adopts model to be the modulus conversion chip of AD7606, CAN communication module adopts model to be the CAN transceiver of SN65HVD235, DA pio chip adopts model to be the analog-digital chip of AD5791, and described signal regulating panel employing model is the chip composition voltage follow device of AD622.

2. the controller of a kind of machine based on DSP according to claim 1 load intelligent pump origin system, it is characterized in that, the minimum circuit of described dsp chip, comprise: the model extended out is the FLASH chip of the 4Mb of SST39VF, model is the SRAM chip of the 2Mb of CY7C1011CV33, with the 1553B module of upper machine communication, chip power supply module, clock circuit and emulator interface circuit; Wherein, 1553B module is model is BU61580 protocol chip; Chip power supply module is used for signal regulating panel transmits the operating voltage that the voltage transitions come is applicable dsp chip; Clock circuit provides stable clock source for dsp chip.

3. the controller of a kind of machine based on DSP according to claim 1 load intelligent pump origin system, it is characterized in that, described intelligent pump origin system controller comprises two pieces of intelligent pump switchboards, every block intelligent pump switchboard comprises two pieces of AD sample circuits and two pieces of DA export and Voltage-current conversion circuit, and signal regulating panel comprises the signal conditioning passage of double amount.

4. the controller of a kind of machine based on DSP according to claim 1 load intelligent pump origin system, it is characterized in that, described Voltage-current conversion circuit, use AD622 to make voltage follow device to be nursed one's health by the voltage that AD5791 exports, the voltage signal after conditioning is amplified by the Current Negative Three-Point Capacitance being made up of LH0041 the electric current signal of circuit conversion one-tenth �� 40mA.