Based on the high-accuracy TME of MSP430F149Technical field
the utility model relates to a kind of temperature measuring equipment, particularly a kind of high-accuracy TME based on MSP430F149.
Background technology
temperature is the physical quantity characterizing the cold and hot degree of object, is one of seven fundamental physical quantities in International System of Units.Be no matter in the various aspects of agricultural, industry, scientific research, national defence and daily life, temperature measure and control all becomes very important problem.In the fields such as industrial or agricultural, scientific research, science and techniques of defence, temperature control precision is particularly important, wherein temperature survey temperature controlled external manifestation just.The measurement to resistance generally all can be changed into the measurement of temperature, so seem particularly important to the precision measurement of resistance in field of temperature measurement.Thermometric accuracy is mainly decided by the accuracy of temperature measurement circuit, and wherein temperature measurement circuit, excitation power supply and sample circuit are the key factors of the accuracy determining temperature measurement circuit.
temperature measurement circuit based on resistance relative method has that temperature-measuring range is large, accuracy is high, steady performance, is a kind of more satisfactory temp measuring method, is industrially widely applied.But because platinum resistance is subject to self error, the systematic error of resistance measurement and the impact such as environment temperature, lead-in wire, temperature measurement accuracy can not reach very high, can be subject to certain restrictions during use.Therefore, study the high precision measuring temperature method based on resistance relative method, raising temperature measurement accuracy is had important practical significance.
Utility model content
a kind of high precision measuring temperature method and apparatus based on MSP430F149 of the present utility model, object is to provide platinum resistance that a kind of temp measuring method overcoming traditional resistance relative method is subject to and is subject to self error, the systematic error of resistance measurement and the impact such as environment temperature, lead-in wire, temperature measurement accuracy can not reach very high, can be subject to certain restrictions during use, reach the method for high-acruracy survey.
the utility model is achieved in that
based on a high-accuracy TME of MSP430F149, it is characterized in that: comprise single-chip microcomputer, power drives, Pt1000 temperature measurement circuit, signal conditioning circuit, A/D change-over circuit, crystal oscillating circuit, reset circuit, display circuit, jtag circuit composition; Described Pt1000 temperature measurement circuit is connected with signal conditioning circuit, signal conditioning circuit is connected with A/D change-over circuit, A/D change-over circuit is connected with single-chip microcomputer, described crystal oscillating circuit is connected with single-chip microcomputer, described reset circuit is connected with single-chip microcomputer, described single-chip microcomputer is connected with display circuit, and jtag circuit is connected with single-chip microcomputer.
described Pt1000 temperature measurement circuit adopts Pt1000 platinum resistance thermometer sensor, as temperature signal collection element.
described A/D change-over circuit adopts AD7712 as analog to digital converter.
described single-chip microcomputer adopts MSP430F149 single-chip microcomputer as control module.
described display circuit adopts LCD1602 liquid crystal as the temperature measuring circuit of display device.
in described circuit, the reference resistance of Pt1000 thermal resistance and known resistance is cascaded, powered by 5V power supply, thermal resistance Pt1000 understands the change of sense temperature and produces corresponding change in voltage, this voltage signal is changing into digital signal through analog to digital converter AD7712 and is being read by Single Chip Microcomputer (SCM) system, Single Chip Microcomputer (SCM) system can carry out identifying processing and calibration the digital signal read, and be converted into the digital signal corresponding with temperature, pass to liquid crystal display by display output temperature value.
a kind of high-accuracy TME based on MSP430F149 is made up of single-chip microcomputer, power drives, Pt1000 temperature measurement circuit, signal conditioning circuit, A/D change-over circuit, crystal oscillating circuit, reset circuit, display circuit, jtag circuit; Power drives provides power supply for single-chip microcomputer and Pt1000 temperature measurement circuit; Pt1000 temperature measurement circuit is connected with signal conditioning circuit, signal conditioning circuit is connected with A/D change-over circuit, and A/D change-over circuit is connected with single-chip microcomputer, and the change in resistance of Pt1000 is passed to single-chip microcomputer; Crystal oscillating circuit is connected with single-chip microcomputer, for single-chip microcomputer provides clock; Reset circuit is connected with single-chip microcomputer, for single-chip microcomputer provides reset; Single-chip microcomputer is connected with display circuit, shows current temperature; Jtag circuit and single-chip microcomputer are connected to single-chip microcomputer and provide JTAG debug function.
a kind of high-accuracy TME based on MSP430F149 be using Pt1000 platinum resistance thermometer sensor, as temperature signal collection element, AD7712 is as analog to digital converter, MSP430F149 single-chip microcomputer as control module, LCD1602 liquid crystal as the temperature measuring circuit of display device; In circuit the reference resistance of Pt1000 thermal resistance and known resistance is cascaded, is powered by 5V power supply; Thermal resistance Pt1000 understands the change of sense temperature and produces corresponding change in voltage, and this voltage signal is changing into digital signal through analog to digital converter AD7712 and read by Single Chip Microcomputer (SCM) system; Single Chip Microcomputer (SCM) system can carry out identifying processing and calibration the digital signal read, and is converted into the digital signal corresponding with temperature, passes to liquid crystal display by display output temperature value.
the beneficial effects of the utility model:
1, the platinum resistance that the temp measuring method overcoming traditional resistance relative method is subject to is subject to self error, resistance measurement
systematic error and the impact such as environment temperature, lead-in wire, make temperature survey to reach degree of precision, reduce use restriction.
2, main control chip adopts the MSP430F149 of low-power consumption, and temperature measurement circuit only can be waken up when there being operation requests executable operations from park mode, is all in low-power consumption mode, reduces the power consumption of system in other mosts of the time.
Accompanying drawing explanation
fig. 1 is system principle structural drawing;
fig. 2 is software flow figure.
Embodiment
below in conjunction with accompanying drawing citing, the utility model is described in more detail:
embodiment 1
composition graphs 1, Fig. 1 is system principle structural drawing of the present utility model.In this design based on the high precision measuring temperature method of resistance relative method, described Pt1000 temperature measurement circuit adopts Pt1000 platinum resistance thermometer sensor, as temperature signal collection element, described A/D change-over circuit adopts AD7712 as analog to digital converter, described single-chip microcomputer adopts MSP430F149 single-chip microcomputer as control module, described display circuit adopts LCD1602 liquid crystal as the temperature measuring circuit of display device, in circuit the reference resistance of Pt1000 thermal resistance and known resistance is cascaded, powered by 5V power supply, thermal resistance Pt1000 understands the change of sense temperature and produces corresponding change in voltage, this voltage signal is changing into digital signal through analog to digital converter AD7712 and is being read by Single Chip Microcomputer (SCM) system, Single Chip Microcomputer (SCM) system can carry out identifying processing and calibration the digital signal read, and is converted into the digital signal corresponding with temperature, passes to liquid crystal display by display output temperature value.Due to the difference of the function of chip selected, this temperature measurement circuit can be divided into each functional circuits such as power driving circuit, A/D change-over circuit, single chip machine controlling circuit, liquid crystal display circuit.
embodiment 2
composition graphs 2, Fig. 2 is software flow figure.In this design, the major function of software is: integrated A/D converter AD7712 converts by A/D the physical signalling measured by temperature sensor Pt100 got to digital signal, then be sent in single-chip microcomputer MSP430F149 and calibrate, finally the digital signal after calibration is shown by liquid crystal display 1602.The thought of application moduleization programming, is divided into several parts such as master routine, data acquisition program, data converter and data display program, so just can realizes the function of system by system software.System master routine is most important part in whole system software, and it is used to all functions that can realize managing temperature measurement circuit.Master routine is the main body of system software, and other subroutine modules can organically link together by it, forms an entirety, calls the subroutine corresponded, complete the realization of function when different operation requests.For subroutines such as data acquisition, conversion, displays, they have been used to the control task relevant with thermometric, and these control tasks have temperature survey, A/D conversion, liquid crystal display etc.
concrete steps are:
1, system initialization.Initialization system clock, the micro-process peripheral hardware of initialization, initialization peripherals.
2, start each functional module program.
3, detected temperatures, and judged whether thermometric.If complete thermometric, then terminate program; If do not complete thermometric, return 2, continue.