CN102778327A - High-performance intelligent sensor digital transmitting system - Google Patents

Abstract

Translated fromChinese

一种高性能、智能传感器数字变送系统，包括传感器，其信号输出端经过小信号无失真放大电路和主处理器单元的输入端连接，主处理器单元的第一输入/输出端和液晶模块连接，主处理器单元的第二输入/输出端和数字隔离器的第一输入/输出端连接，数字隔离器的第二输入/输出端通过RS485总线处理器和变送器接口连接，主处理器单元的第三输入/输出端经4-20mA回路信号、4-20mA隔离器件和变送器接口连接，电源处理模块提供流源的电压，主处理器单元将参数优化后显示在液晶显示模块上，并通过RS-485总线处理器将数据上传到总线上，并利用修正后的压力值转换成两线制4-20mA回路信号，本发明具有高精度、智能化的优点。

A high-performance, intelligent sensor digital transmission system, including a sensor, its signal output terminal is connected to the input terminal of the main processor unit through a small signal distortion-free amplifier circuit, the first input/output terminal of the main processor unit and the liquid crystal module Connection, the second input/output terminal of the main processor unit is connected with the first input/output terminal of the digital isolator, the second input/output terminal of the digital isolator is connected with the transmitter interface through the RS485 bus processor, the main processing unit The third input/output terminal of the transmitter unit is connected to the interface of the transmitter through the 4-20mA loop signal, the 4-20mA isolation device, the power processing module provides the voltage of the current source, and the main processor unit optimizes the parameters and displays them on the liquid crystal display module and upload the data to the bus through the RS-485 bus processor, and use the corrected pressure value to convert it into a two-wire 4-20mA loop signal. The invention has the advantages of high precision and intelligence.

Description

A kind of high-performance, intelligence sensor numeral transmitting system

Technical field

The present invention relates to pressure transducer transmitter technical field, particularly a kind of high-performance, intelligence sensor numeral transmitting system.

Background technology

Transmitter is a kind of pick-up unit that is widely used in petrochemical industry.The function of transmitter mainly is the electric signal that the dissimilar non-electrical signals of pressure transducer output is changed into industrial standard, like 4-20mA current signal, 1-5V voltage signal.Through this type of conversion, receivable analog quantity electric signal just can be transferred on hundreds of the rice outer pulpit or display device.

Existing pressure transducer transmitter mainly realizes pressure signal is changed into the function of electric signal, but the precision of this type of transmitter is generally lower.Because the linearity that output showed of pressure transducer under different temperature is different, the existence that temperature is floated makes the output of sensor itself have nonlinear feature.Bring temperature into through the signal of traditional transmitter conversion and floated, greatly reduced the precision of transmitter.Both at home and abroad relevant industries are devoted to study the solution of the problem of floating to temperature always, do not float problem but existing transmitter industry proposes the temperature that a kind of intelligent transfer mode comparatively reliably solves sensor as yet.

Summary of the invention

In order to overcome the defective of above-mentioned prior art, the object of the present invention is to provide a kind of high-performance, intelligence sensor numeral transmitting system, have high precision, high-performance, intelligentized advantage.

In order to achieve the above object, the technical scheme taked of the present invention is:

A kind of high-performance, intelligence sensor numeral transmitting system;Comprise sensor 1; The signal output part ofsensor 1 is connected with the input end of the undistorted amplifyingcircuit 2 of small-signal; Small-signal is undistorted, and the output terminal of amplifyingcircuit 2 and the input end ofmain processor unit 3 are connected; The first I/O end ofmain processor unit 3 is connected with Liquid CrystalModule 4; Second I/O end ofmain processor unit 3 and the first I/O end ofdigital isolator 5 are connected, and the second I/O end ofdigital isolator 5 is connected with the transmitter interface through RS485bus processor 7, and the 3rd I/O end ofmain processor unit 3 and the I/O end of 4-20mA loop signal 6 are connected; The output terminal of 4-20mA loop signal 6 is connected with the input end of 4-20mA isolating device 8; The output terminal of 4-20mA isolating device 8 is connected with the transmitter interface, and the power input ofpower management module 9 andsensor 1, small-signal is undistorted amplifyingcircuit 2,main processor unit 3 is connected, andpower circuit protection 11 is connectedpower management module 9 through isolated frompower 10 and before isolating; The final transmitter interface that inserts,power management module 9 and isolated frompower 10, the precedingpower circuit protection 11 common powersupply processing modules 12 of forming of isolation.

Describedmain processor unit 3 adopts ATMEGA128L, utilizes the least square regression algorithm that the signal thatsensor 1 is sent is carried out intelligent compensation, utilizes host computer proving operation software that original signal is revised.

Describedpower management module 9 adopts Ultra-High-Precision, Ultra-Low-Noise, and Series Voltage Reference provides as the voltage of constant current source, and maximum noise is 1.3 μ VP-P, and switching noise is 35nV/ √ Hz.

Good reliability of the present invention, measuring accuracy is high, has effectively promoted the system accuracy of sensor.Simultaneously, the present invention should have good Electro Magnetic Compatibility, and its Electro Magnetic Compatibility index should satisfy GJB151A-1997 " military equipment and subsystem Electromagnetic Launching and susceptibility require ".

Description of drawings

Fig. 1 is a system architecture synoptic diagram of the present invention.

Fig. 2-(a) ismain processor unit 3 circuit diagrams, and Fig. 2-(b) is the circuit diagram of undistorted amplifyingcircuit 2 of small-signal and 4-20mA loop signal 6, and 2-(c) is the circuit diagram of powersupply processing module 12.

Embodiment

Below in conjunction with accompanying drawing the present invention is elaborated.

With reference to Fig. 1; A kind of high-performance, intelligence sensor numeral transmitting system comprisesensor 1, and the signal output part ofsensor 1 is connected with the input end of the undistorted amplifyingcircuit 2 of small-signal; Original signal is modulated into the 4-20mA current signal of industrial standard through the undistorted amplifyingcircuit 2 of small-signal; Small-signal is undistorted, and the output terminal of amplifyingcircuit 2 and the input end ofmain processor unit 3 are connected, and the signal after the modulation insertsmain processor unit 3, and the first I/O end ofmain processor unit 3 is connected with Liquid CrystalModule 4; Signal carries out corresponding compensation inmain processor unit 3 after; Output on the Liquid CrystalModule 4 in order to show that the second I/O end ofmain processor unit 3 and the first I/O end ofdigital isolator 5 are connected, the second I/O end ofdigital isolator 5 passes through RS485bus processor 7 and is connected with the transmitter interface; Signal afterMain Processor Unit 3 will be handled throughdigital isolator 5 sends to the transmitter interface through RS485bus processor 7; To feed to master station's communication, the 3rd I/O end ofmain processor unit 3 and the I/O end of 4-20mA loop signal 6 are connected, and the output terminal of 4-20mA loop signal 6 is connected with the input end of 4-20mA isolating device 8; The output terminal of 4-20mA isolating device 8 is connected with the transmitter interface; Electric signal after will modulating through 4-20mA loop signal 6 sends to the transmitter interface, makes transmitter can send the accurate 4-20mA electric signal of a road sign and uses for expansion, between 4-20mA loop signal 6 and the transmitter interface 4-20mA isolating device 8 is arranged; Digital signal and simulating signal in the circuit are isolated fully; Improve the signal to noise ratio (S/N ratio) of signal, the power input ofpower management module 9 andsensor 1, small-signal is undistorted amplifyingcircuit 2,main processor unit 3 is connected, and tosensor 1, small-signal is undistorted amplifyingcircuit 2,main processor unit 3 corresponding stabilized power source is provided throughpower management module 9;Power management module 9 is connected through the precedingpower circuit protection 11 of isolated frompower 10 and isolation; The final transmitter interface that inserts owing to having added isolated frompower 10 protection modules, has promoted the stability of power supply; Reduced the ripple noise of power supply,power management module 9 and isolated frompower 10, the precedingpower circuit protection 11 common powersupply processing modules 12 of forming of isolation.

With reference to Fig. 2-(a); Describedmain processor unit 3 has been selected ATMEGA128L for use; Utilize the least square regression algorithm that the signal thatsensor 1 is sent is carried out intelligent compensation, utilize host computer proving operation software that original signal is revised, according to certain frequency sampling;Main processor unit 3 is presented at sampled data on theLCD MODULE 4 after according to the parameter optimization of revising; And upload the data on the bus through RS-485bus processor 7, and utilize revised force value to convert two-wire system 4-20mA loop signal 6 to, calibration system is calibration sensor intelligent digital transmitter and can effectively promote the system accuracy of sensor easily.The inner least square regression algorithm that adopts of single-chip microcomputer carries out linear compensation to the output of sensor, adopts many temperature spots multiple pressure force to demarcate, and between adjacent two temperature spots, carries out match again, thereby makes transmitter reach full accuracy in the total temperature scope.

ATMEGA128L is a kind of high-performance single-chip microcomputer, adopts its inner 1 tunnel 16 high-speed a/d converter and 1 tunnel 10 A/D converter, and one tunnel acquired signal one tunnel is gathered baseline; Adopt 2 tunnel 12 D/A converters, the output of one tunnel control baseline, one tunnel control, 4 ~ 20mA signal.The high-precision high-speed analog to digital converter be high precision transmitter (0.1%FS or 0.05%FS) provide maybe, its inner integrated 64KFLASH storer has been cancelled the outside EEPROM that is used for data table memory in addition, has simplified external circuit.

With reference to Fig. 2-(b), this figure is the circuit diagram of undistorted amplifyingcircuit 2 of small-signal and 4-20mA loop signal 6.Native system is selected high performance front-end amplifier for use, improves the inhibition ability of amplifying circuit to interference noise.Adopt low-pass filter to suppress high frequency interference, adopt the instrument amplifier of high cmrr to suppress common mode interference.Automatically the method for baseline adopts the reference edge of 12 D/A control instrument amplifiers, thereby realizes the inhibition of temperature drift, baseline wander, linear drift automatically.Instrument amplifier adopts the AD623 of U.S. ADI company, and its common-mode rejection ratio is greater than 90dB.Precision amplifier adopts the OPA335 of American TI Company.

With reference to Fig. 2-(c), this figure is the circuit diagram of power supply processing module 12.Circuit protection designs such as anti-thunderbolt, surge inhibition have been added in this design, make that the stability of native system is more remarkable, under extreme environment, can guarantee the normal operation of system.Describedpower management module 9 adopts Ultra-High-Precision, Ultra-Low-Noise, and Series Voltage Reference provides as the voltage of constant current source, and maximum noise is 1.3 μ VP-P, and switching noise is 35nV/ √ Hz.

Principle of work of the present invention is:

With reference to Fig. 1, the signal that a kind of high-performance, intelligence sensor numeral transmitting system are sent through receivingsensor 1 is modulated into the electric signal thatmain processor unit 3 can be used with signal through the undistorted amplifyingcircuit 2 of small-signal.The technical indicator of amplifying circuit is frequency analog signal response 0.01 ~ 100KHz, conjugated analoging systeming ratio>90dB, input impedance>5M Ω, input dynamic range 0 ~ 500mV, SF 1MHz.Amplifying circuit adopts three grades of structure for amplifying, and the enlargement factor of each grade all is not more than 10 times, and first order instrument amplifier enlargement factor is 5 times, and its effect mainly is to convert differential signal to mono signal, and the conjugated analoging systeming ratio of 90dB is provided.Second level amplifier adopts reverse input, and enlargement factor is 2 times, and its effect mainly is to form a low-pass filter, and signal to noise ratio (S/N ratio) is significantly promoted.Third level amplifier adopts reverse input, and enlargement factor is 10 times, and its effect mainly is that signal amplifies, and converts reverse signal to forward signal, at last signal is carried out filter shape, and offers the 16-bitA/D converter.

Aftermain processor unit 3 is demarcated through upper computer software, with being presented on the Liquid CrystalModule 4 after the parameter optimization of the signal that receives through the sampled data correction.The correction of data utilizes the least square regression fitting algorithm.Adopt many temperature spots multiple pressure force to demarcate, between adjacent two temperature spots, carry out match again, thereby make transmitter reach full accuracy in the total temperature scope.Simultaneously, this intelligent digital transmitting system also through RS485bus processor 7, sends the current pressure value that is collected according to certain agreement, can be used for remote monitoring.In addition, the intelligent digital transmitting system also pressure signal is modulated into industrial standard through 4-20mA loop signal 6,4-20mA isolating device 8 the 4-20mA current signal in order to output.

The present invention adopts constant current source as excitation, and whether system's constant current source design precisely is directly connected to the accuracy of pressure transducer acquired signal.The present invention adopts Ultra-High-Precision, Ultra-Low-Noise, and Series Voltage Reference provides as the voltage of constant current source, and maximum noise is 1.3 μ VP-P, and switching noise is 35nV/ √ Hz.Simultaneously, the native system circuit protection adopts three grades of lightning surge protection circuits, and its protective capacities meets and surpasses IEC61000-4-5, and ITU-T K20/K21 and GB GB9043 are all relevant for lightning surge immunity to interference testing standard.The highest testing standard of its communication line is 10/700us, 4KV.10/700us is the lightning voltage waveform that induces in the communication line, and it is that the time is 10us that expression rises to peak value from null value, drops to the half the 700us of being of peak value.

Claims (3)

1. a high-performance, intelligence sensor numeral transmitting system; Comprise sensor (1); It is characterized in that: the signal output part of sensor (1) is connected with the input end of the undistorted amplifying circuit of small-signal (2); The output terminal of the undistorted amplifying circuit of small-signal (2) is connected with the input end of main processor unit (3); The first I/O end of main processor unit (3) is connected with Liquid Crystal Module (4); The second I/O end of main processor unit (3) is connected with the first I/O end of digital isolator (5); The second I/O end of digital isolator (5) is connected with the transmitter interface through RS485 bus processor (7); The 3rd I/O end of main processor unit (3) is connected with the I/O end of 4-20mA loop signal (6), and the output terminal of 4-20mA loop signal (6) is connected with the input end of 4-20mA isolating device (8), and the output terminal of 4-20mA isolating device (8) is connected with the transmitter interface; Power management module (9) is connected with the power input of sensor (1), the undistorted amplifying circuit of small-signal (2), main processor unit (3); Power management module (9) protects (11) to be connected through isolated from power (10) with isolating preceding power circuit, finally inserts the transmitter interface, and power circuit protects (11) to form power supply processing module (12) jointly before power management module (9) and isolated from power (10), the isolation.

2. a kind of high-performance according to claim 1, intelligence sensor numeral transmitting system; It is characterized in that: described main processor unit (3) adopts ATMEGA128L; Utilize the least square regression algorithm that the signal that sensor (1) is sent is carried out intelligent compensation, utilize host computer proving operation software that original signal is revised.

3. a kind of high-performance according to claim 1, intelligence sensor numeral transmitting system; It is characterized in that: described power management module (9) adopts Ultra-High-Precision; Ultra-Low-Noise; Series Voltage Reference provides as the voltage of constant current source, and maximum noise is 1.3 μ VP-P, and switching noise is 35nV/ √ Hz.

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