阅读说明：本技术 一种智能化的电流输出传感器信号调理电路及调理方法 (Intelligent current output sensor signal conditioning circuit and conditioning method ) 是由 刘敏侠 田泽 邵刚 蒲石 余立宁 胡曙凡 权炜 于 2020-12-24 设计创作，主要内容包括：本发明涉及一种智能化的电流输出传感器信号调理电路及调理方法。本发明包括铂电阻温度传感器RTD、多个精密电阻RZ、多路选通器、第一级可编程增益放大器PGA1、第二级可编程增益放大器PGA2、线性化电路、接口SPI和高精度电压电流转换器V/I,铂电阻温度传感器RTD上并联多个精密电阻RZ,铂电阻温度传感器RTD和多个精密电阻RZ通过多路选通器接入第一级可编程增益放大器PGA1,第一级可编程增益放大器PGA1输出接入第二级可编程增益放大器PGA2输入端,第二级可编程增益放大器PGA2一路接高精度电压电流转换器V/I,另一路通过线性化电路反馈至第一级可编程增益放大器PGA1,接口SPI接第一级可编程增益放大器PGA1。本发明具有集成化程度高、操作简单、补偿精度高、并且试用范围广的优点。(The invention relates to an intelligent current output sensor signal conditioning circuit and a conditioning method. The invention comprises a platinum resistance temperature sensor RTD, a plurality of precision resistors RZ, a multi-way gate, a first-stage programmable gain amplifier PGA1, a second-stage programmable gain amplifier PGA2, a linearization circuit, an interface SPI and a high-precision voltage-current converter V/I, wherein the platinum resistance temperature sensor RTD is connected with a plurality of precision resistors RZ in parallel, the platinum resistance temperature sensor RTD and the precision resistors RZ are connected into the first-stage programmable gain amplifier PGA1 through the multi-way gate, the output of the first-stage programmable gain amplifier PGA1 is connected into the input end 387 of the second-stage programmable gain amplifier PGA2, one path of the second-stage programmable gain amplifier PGA2 is connected with the high-precision voltage-current converter V/I, the other path is fed back to the first-stage programmable gain amplifier PGA1 through the linearization circuit, and the interface SPI is. The invention has the advantages of high integration degree, simple operation, high compensation precision and wide trial range.)

1. The utility model provides an intelligent current output sensor signal conditioning circuit which characterized in that: the conditioning circuit comprises a platinum resistance temperature sensor RTD, a plurality of precision resistors RZ, a multi-way gate, a first-stage programmable gain amplifier PGA1, a second-stage programmable gain amplifier PGA2, a linearization circuit, an interface SPI and a high-precision voltage-current converter V/I, the platinum resistance temperature sensor RTD is connected with a plurality of precision resistors RZ in parallel, the platinum resistance temperature sensor RTD and the precision resistors RZ are connected into a first-stage programmable gain amplifier PGA1 through a multi-way gate, the output of the first-stage programmable gain amplifier PGA1 is connected to the input of the second-stage programmable gain amplifier PGA2, one path of the second-stage programmable gain amplifier PGA2 is connected with the high-precision voltage-current converter V/I, the other path is fed back to the first-stage programmable gain amplifier PGA1 through the linearization circuit, and the interface SPI is connected with the first-stage programmable gain amplifier PGA 1.

2. The intelligent current output sensor signal conditioning circuit of claim 1, wherein: the conditioning circuit further comprises a memory EEPROM, a current DAC1, and a current DAC 2; the memory EEPROM is connected with an interface SPI which is connected with a multiplexer through a current DAC1 and connected between a first-stage programmable gain amplifier PGA1 and a second-stage programmable gain amplifier PGA2 through a current DAC 2.

3. The intelligent current output sensor signal conditioning circuit of claim 2, wherein: the conditioning circuit further comprises an oscillator OSC, and the oscillator OSC is connected with the interface SPI.

4. The intelligent current output sensor signal conditioning circuit of claim 3, wherein: the current DAC1 is connected to the multiplexer via a two-way current source I1 and a current source I2.

5. The intelligent current output sensor signal conditioning circuit of claim 4, wherein: the platinum resistance temperature sensor RTD is grounded through a load resistor Rcm.

6. The intelligent current output sensor signal conditioning circuit of any one of claims 1 to 5, wherein: the number of the precision resistors RZ is 5.

7. A method of conditioning a circuit implementing the intelligent current output sensor signal conditioning of claim 1, characterized by: the method comprises the following steps:

1) connecting a platinum resistance temperature sensor RTD, configuring different precision resistors Rz according to the application temperature range, and selecting by a multi-channel gate;

2) the input stage carries out differential input on the current flowing through the platinum resistance temperature sensor RTD and the current flowing through the precision resistor Rz, the input signal is subjected to variable gain amplification through a first-stage programmable gain amplifier PGA1 and then is output, and the gain value is controlled by an SPI (serial peripheral interface);

3) after the signal passes through the second-stage programmable gain amplifier PGA2, the output of the sampling part is fed back to the linearization circuit to control the input of the linearization circuit, and the linearization degree of the input signal is adjusted;

4) and outputting the final signal through a second-stage programmable gain amplifier PGA2, and converting the final signal into a required current of 4-20 mA through a high-precision voltage-current converter V/I to be output.

8. The intelligent current output sensor signal conditioning method of claim 7, wherein: the method also comprises a step 5) of writing data needing configuration into the internal unit in advance by the memory EEPROM through the interface SPI, directly loading the data by the internal unit when the platinum resistance temperature sensor RTD is actually applied, and controlling the gain of the first-stage programmable gain amplifier PGA1, the size configuration of the current DAC1 and the size configuration of the current DAC 2.

9. The intelligent current output sensor signal conditioning method of claim 8, wherein: the method further comprises step 6) the clock signal, the reference voltage and the reference current required for the operation of the conditioning circuit are provided by the oscillator OSC and the reference circuit.

Technical Field

The invention relates to the field of signal communication of aviation, navigation, industrial control and the like, in particular to an intelligent current output sensor signal conditioning circuit and a conditioning method.

Background

The platinum resistor is a temperature sensor with a very wide application range, and when a resistive sensor signal is transmitted, input drift and nonlinearity greatly affect the characteristics of the sensor, so that the input signal needs to be conditioned and converted into available 4-20 mA for transmission. The existing scheme mostly adopts hardware resistance calibration and conditioning, adopts a scheme of hardware resistance compensation, and provides higher requirements for system engineers, each sensor needs to independently adjust a compensation resistance, and simultaneously needs to master the system performance thoroughly, and is externally connected with a high-precision resistance, the precision of the resistance determines the precision of the final whole system, intelligent configuration cannot be carried out, and batch processing is difficult to carry out in production.

Disclosure of Invention

The invention provides an intelligent current output sensor signal conditioning circuit and a conditioning method for solving the technical problems in the background technology, and has the advantages of high integration degree, simplicity in operation, high compensation precision and wide trial range.

The technical solution of the invention is as follows: the invention relates to an intelligent current output sensor signal conditioning circuit, which is characterized in that: the conditioning circuit comprises a platinum resistance temperature sensor RTD, a plurality of precision resistors RZ, a multi-way gate, a first-stage programmable gain amplifier PGA1, a second-stage programmable gain amplifier PGA2, a linearization circuit, an interface SPI and a high-precision voltage-current converter V/I, wherein the platinum resistance temperature sensor RTD is connected with the plurality of precision resistors RZ in parallel, the platinum resistance temperature sensor RTD and the plurality of precision resistors RZ are connected into the first-stage programmable gain amplifier PGA1 through the multi-way gate, the output of the first-stage programmable gain amplifier PGA1 is connected into the input end 387 of the second-stage programmable gain amplifier PGA2, one path of the second-stage programmable gain amplifier PGA2 is connected with the high-precision voltage-current converter V/I, the other path is fed back to the first-stage programmable gain amplifier PGA1 through the linearization circuit, and the interface SPI.

Preferably, the conditioning circuit further comprises memory EEPROM, current DAC1, and current DAC 2; the memory EEPROM is connected with an interface SPI which is connected with the multiplexer through a current DAC1 and is connected between the first-stage programmable gain amplifier PGA1 and the second-stage programmable gain amplifier PGA2 through a current DAC 2.

Preferably, the conditioning circuit further comprises an oscillator OSC, and the oscillator OSC is connected to the interface SPI. The oscillator OSC provides the conditioning circuit with the clock signal required for operation.

Preferably, the current DAC1 is connected to the multiplexer via a two-way current source I1 and a current source I2.

Preferably, the platinum resistance temperature sensor RTD is grounded through a load resistance Rcm.

Preferably, the precision resistance RZ is 5.

A conditioning method for realizing the intelligent current output sensor signal conditioning circuit is characterized in that: the method comprises the following steps:

1) connecting a platinum resistance temperature sensor RTD, configuring different precision resistors Rz according to the application temperature range, and selecting by a multi-channel gate;

2) the input stage carries out differential input on the current flowing through the platinum resistance temperature sensor RTD and the current flowing through the precision resistor Rz, the input signal is subjected to variable gain amplification through a first-stage programmable gain amplifier PGA1 and then is output, and the gain value is controlled by an SPI (serial peripheral interface);

3) after the signal passes through the second-stage programmable gain amplifier PGA2, the output of the sampling part is fed back to the linearization circuit to control the input of the linearization circuit, and the linearization degree of the input signal is adjusted;

4) and outputting the final signal through a second-stage programmable gain amplifier PGA2, and converting the final signal into a required current of 4-20 mA through a high-precision voltage-current converter V/I to be output.

Preferably, the method further comprises a step 5) of writing data to be configured into the internal unit in advance from the memory EEPROM through the interface SPI, and directly loading the data from the internal unit when the platinum resistance temperature sensor RTD is actually used to control the gain of the first-stage programmable gain amplifier PGA1, the size configuration of the current DAC1 and the size configuration of the current DAC 2.

Preferably, the method further comprises the step 6) of providing a clock signal, a reference voltage and a reference current required by the operation of the conditioning circuit by the oscillator OSC and the reference circuit, so as to ensure the circuit accuracy and improve the overall performance of the circuit.

The platinum resistor is used as a temperature sensor, certain output error and nonlinearity exist, the intelligent signal conditioning circuit and the conditioning method of the current output sensor provided by the invention process the nonlinearity of the platinum resistor while amplifying and converting the signal, supply power to the platinum resistor at a constant current, amplify a small signal at an input end, and then convert the small signal into high-precision controllable current output, wherein the gain and nonlinear feedback output are controlled by a digital circuit part, so the invention has the following advantages:

1. according to the invention, through an intelligent current output sensor signal conditioning circuit framework, the single-chip integrated circuit is adopted, amplification, storage and nonlinear calibration are all integrated in one chip, and the integration degree is high.

2. The invention selects different zero setting resistors Rz through different application ranges, can realize the intelligent transmission of the configuration of the platinum resistor through digital configuration, and has the advantages of simple operation, high compensation precision and wide trial range.

Drawings

Fig. 1 is a circuit schematic of the present invention.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, the structure of the embodiment of the present invention includes a platinum resistance temperature sensor RTD, a plurality of precision resistors RZ, a multiplexer, a first stage programmable gain amplifier PGA1, a second stage programmable gain amplifier PGA2, a linearizer, an interface SPI, a memory EEPROM, a current DAC1, a current DAC2, an oscillator OSC, and a high precision voltage-to-current converter V/I, the platinum resistance temperature sensor RTD is connected in parallel with the plurality of precision resistors RZ, in the embodiment, the number of precision resistors RZ configured according to the application temperature range of the platinum resistance temperature sensor RTD is 5, and is divided into RZ 1-RZ 5, one end of the platinum resistance temperature sensor RTD is grounded through a load resistor Rcm, the other end and the 5 precision resistors RZ 1-RZ 5 are connected to the first stage programmable gain amplifier PGA1 through the multiplexer, the output of the first stage programmable gain amplifier 1 is connected to the input end of the second stage programmable gain amplifier PGA2, one path of the second-stage programmable gain amplifier PGA2 is connected with the high-precision voltage-current converter V/I, the other path is fed back to the first-stage programmable gain amplifier PGA1 through the linearization circuit, the memory EEPROM is connected with the interface SPI, the interface SPI is divided into three paths, the first path is connected with the multi-path gate through the current DAC1, the current DAC1 is connected with the multi-path gate through the two paths of the current source I1 and the current source I2, the second path is connected with the first-stage programmable gain amplifier PGA1, the third path is connected between the first-stage programmable gain amplifier PGA1 and the second-stage programmable gain amplifier PGA2 through the current DAC2, and the oscillator OSC.

Wherein the linearizer is an existing linearizer.

The invention also provides a conditioning method of the intelligent current output sensor signal conditioning circuit for realizing the specific embodiment, which comprises the following steps:

1) connecting a platinum resistance temperature sensor RTD, configuring different precision resistors Rz according to the application temperature range, and selecting by a multi-channel gate;

2) the input stage carries out differential input on the current flowing through the platinum resistance temperature sensor RTD and the current flowing through the precision resistor Rz, the input signal is subjected to variable gain amplification through a first-stage programmable gain amplifier PGA1 and then is output, and the gain value is controlled by an SPI (serial peripheral interface);

3) after the signal passes through the second-stage programmable gain amplifier PGA2, the output of the sampling part is fed back to the linearization circuit to control the input of the linearization circuit, and the linearization degree of the input signal is adjusted;

4) the final signal is output through a second-stage programmable gain amplifier PGA2, and then converted into the required 4-20 mA current output through a high-precision voltage-current converter V/I;

5) data needing to be configured is written into an internal unit in advance through an interface SPI by a memory EEPROM, the internal unit is directly loaded when the platinum resistance temperature sensor RTD is actually applied, and the gain of a first-stage programmable gain amplifier PGA1, the size configuration of a current DAC1 and the size configuration of a current DAC2 are controlled;

6) clock signals, reference voltage and reference current required by the working of the conditioning circuit are provided by the oscillator OSC and the reference circuit, so that the overall performance of the circuit is improved while the circuit precision is ensured.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.