热量计系统毕业设计.rar

热量计系统毕业设计

摘要

城市集中供热的能源浪费及不合理的按住宅面积收费问题日益突出，已经制约了城市集中供热的进一步发展。热量表是实施城市供热体制改革，推行按热量收费的关键设备，对热量消耗全部智能计算，以用户实际耗用热量为计量收费依据。热量表作为热力公司向每一位住户收费的依据和手段，不仅己广泛被用户所接受，而且由于用热量与费用直接相关，也加强了住户的节能意识。用热量表进行热计量更为科学、更为合理，既方便用户，又便于管理。而本课题研究的目的就是为人们提供一种能够准确测量热量消耗，解决收费难的智能仪表。
本次设计就热量计的原理进行了简单论述，通过把工程热力学中的能量平衡方程应用到热量表中，得出了适合热量表热量计量的公式；并且对热量表硬件的各个主要组成单元：主控制单元、流量测量单元以及配对温度传感器等都进行了比较分析，选择性能稳定、价格低廉的器件，其中流量传感器选择的是电极式无磁流量传感器，它属于叶轮流量传感器的一种。温度传感器选择的是铂电阻温度传感器，主控制单元的核心器件选用的是at89c51型号的单片机。就此完成了主要硬件部分的设计。
本文也设计了相应的软件程序，软件程序采用C语言进行的编写，把整体程序由系统初始化程序、测温子程序、测流量子程序和按键中断等几部分组成。最后，对热量表进行了系统调试，调试成功后进行测试，成功地实现了热量计量和显示。
关键词：热量计；单片机；温度传感器；流量传感器

Abstract

The problem of energy waste as result of urban central heating and unreasonable charge according to the areas is ourstanding day by day.This problem has already restricted the further development of urban central heating.The calorimeter is crucial equipment which implements system reform of urban heat supply and charges according to heat.It measures and charges on the basis of the user consumption heat actual.The administration adopt heat meter to measure heat that not only facilitates the users,but easy to manage.The purpose of researching the subject to offer users a kind of intelligence instrument that can accurately measure heat consumption and solve the difficult of charging.
The theory of heat measurement is analyzed.The energy-balance equation in the engineering thermodynamics is used to propose the equation of quantity of heat measurement for heat meter.This is the theory basis for heat measurement.steadier performance and lower price consuming have been chosen by comparing and analyzing each piece of the mainly constitute module of the heat meter’s hardwar,which is constitute by the main controlling unit,flow meter,couples temperature sensor etc. Electrode-free magnetic flow sensor has been chosen as the flow sensor,which is a kind of Impeller flow sensor. Platinum resistance temperature sensor has been chosen as temperature sensor,and at89c51 singlechip has been chosen as the centre of  the main controlling unit.Thus the designation of the hardware electric circuit is completed.
This paper design a software which is writed by C language corresponded to the hardware electric circuit.The whole program consist of flux measurement,heat measurement,the key pause and the system initialize program.Finally,it makes a system debug to heat meter,and test after successful debug.
Key words:calorimeter;singlechip;temperature sensor;flow sensor

目录

0  前言 1
1  概述 2
1.1  我国供热现状和开发热量计的现实意义 2
1.2  热量计概述 3
1.3  热量计的国外发展状况 4
2  热量计的硬件电路设计 7
2.1  热量计量系统原理框图 7
2.2  热量计计热原理 7
2.3  热量计的硬件原理框图 9
2.4  信号处理部分 10
2.4.1  单片机简介 10
2.4.2  51单片机结构概述 11
2.5  单片机选择 13
2.6  单片机外围电路设计 15
2.6.1  复位电路设计 15
2.6.2  锁存器74LS373 15
2.6.3  译码器74LS138 16
2.6.4  外部数据存储器的选择 17
2.7  温度采集电路设计 18
2.7.1  温度传感器的选择 18
2.7.2  测温原理理论分析 19
2.7.3  电阻—温度变换处理 19
2.7.4  差动放大器 22
2.7.5  A/D转换器 23
2.7.6  温度测量电路 26
2.8  流量采集电路 27
2.8.1  流量传感器 27
2.8.2  电极式无磁流量计介绍 28
2.8.3  流量传感器电路设计 29
2.9  显示部分设计 30
3  系统软件设计 31
3.1  主程序流程图 31
3.2  初始化模块设计 32
3.3  温度测量子程序 33
3.4  流量测量子程序 34
3.5  热量计算子程序 36
3.6  按键中断子程序 37
4  技术经济分析 41
4.1  需求分析 41
4.2  经济效益分析 42
4.3  社会效益分析[13] 42
4.4  技术可靠性分析 42
5  结论 44
致谢 45
参考文献 46
附录A   译文 47
附录B   外文原文 56
附录C  整体程序 67