chapt1--Fundamentals of measurements放映1.ppt

* Chapter 1Fundamentals of Measurements class01.ppt Objectives When you finish this chapter, you will be able to: Understand the definition of measurement and instrument; Have a general grasp of measuring system; Master the error theory and their corresponding usages; Understand the characteristics of instruments and their usages. What is measurement? What is instrument? The process of gathering information from the physical world and comparing it with agreed stands Mathematics Description Where, X——measurand X0——standards K——result 1.1.1 Definition of Measurement (测量) 例1 用精度为0.5%，测量范围为0~500mm的直尺 测量容器液位高度，得到X=350mm。 Standard ：mm Result ：350 Error ：2.5mm 确定基准单位， 将被测变量与基准单位比较， 估计测量结果的误差 信息转换 检测是更广泛的测量概念 1.1.2 Definition of Instrument (仪表) A device for recording, measuring, or controlling, especially such a device functioning as part of a control system. 1.1.3 Definition of Sensors (传感器) A sensor is a device that receives a signal or stimulus and responds with an signal. The term sensor （传感器）should be distinguished from transmitter（变送器）. A sensor converter of one type of energy into another A transmitter converts any type of energy into electrical. 1.2 Instrument classification According to input parameters of sensor (measured parameters) Temperature; Pressure; Flow; Level; Displacement; Speed; Other According to output parameters of sensor Analog sensor; Digital sensor According to detection means used in sensor Biological ; Chemical; Electrical; Mechanical; Radioactivity; Other 1 Basic Concept 1.1 Definition (measurement, instrument, sensor) 1.2 Instrument classification 1.3 The measuring system Any measuring system can be broadly represented by the three-block diagram. The block represent the following functional elements. A sensor A signal conditioner A recorder or display Transmitter Primary quantities Sensor Signal conditioner Recorder or display Fig 1.1 Block diagram of a basic measurement system Conditioned signal Transduced