A Study On An Intelligent Strain Measuring System

The strain measuring system is a commonly used measuring system.It has the advantages of high precision,wide measuring range,simple structure and good frequency response characteristics.It can also work in harsh conditions.With the development of sensor technology,communication technology and computer technology,the intelligent strain measuring system with the functions of storing sensor information and connecting network has become a development trend.Under this background and according to the IEEE1451 standards,this thesis designed an intelligent strain measuring system based on STM32F103.The system includes a smart transducer interface module(STIM),a network capable application processor(NCAP),an upper computer software,an instruction system and three transducer electronic data sheets(TEDS).The smart transducer interface module uses IIC to communicate with the network capable application processor which uses WIFI to communicate with the upper computer software and acts as the communication bridge between the smart transducer interface module and the upper computer software.The transducer electronic data sheets mainly used to store the information about the smart transducer interface module and the sensor.This paper first introduced the standards of IEEE1451,and then designed the overall framework of the measuring system by referring the standards.Then the key technologies were studied,and the hardware or software of each module were designed,and thus the design of the overall scheme was achieved.The main research tasks of the thesis are detailed as follows:(1)The overall design of the measuring system.The overall design adopts the client/server mode in which the upper computer software acts as the client,while the network capable application processor as the server,and the smart transducer interface module performs specific operations.The design focuses include the interface workflow between the network capable application processor and the smart transducer interface module,as well as a concise instruction system which aims to make the system easy to maintain and extend.(2)The design of the smart transducer interface module.The smart transducer interface module,whose functions mainly include instruction processing,data measurement,information transmission and the storage for the transducer electronic data sheets,primally consists of a strain sensor module and a STM32F103.The formats of the transducer electronic data sheets designed in this module are more convenient for transmission and storage.(3)The design of the network capable application processor.The network capable application processor,which mainly includes a STM32F103 and a ESP8266 network module,is primally used to realize its WIFI communication with the upper computer software,analyze the instructions of the upper computer and send them to the smart transducer interface module,intelligently identify the smart transducer interface module,receive the data sent by the smart transducer interface module and send them to the upper computer software.(4)The design of the upper computer software.The upper computer software,a form program coded in the Visual Studio by using C#,mainly realizes the generation,marking and sending of instructions,as well as the calculation,display,storage and query for the received results of the instructions.The upper computer software has a login interface which makes the use of the software more secure.The experimental results has showed that the smart transducer interface module can store the information about itself and the sensor,and can realize the plug-and-play capability of the strain sensor module.Besides,the network capable application processor can make the smart transducer interface module achieve its plug-and-play capability.Moreover,the upper computer software can send instructions,receive and manage results,as well as achieve real-time monitoring of the connection status between itself and the network capable application processor.