上游充通大￥ SHANGHAI JIAO TONG UNIVERSITY Chapter 2 Generalized Configurations Functional Descriptions of Measuring Instruments by Yixin Ma 27/02/2013 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY Contents 1.Functional Elements of an Instrument 2.Active and Passive Transducers 3.Analog and Digital Modes of Operation 4.Null and Deflection Methods 5.Input-Output Configuration of Instruments and Measurement Systems 6.Methods of Correction for Interfering and Modifying Inputs 7.Conclusions
Chapter 2 Generalized Configurations & Functional Descriptions of Measuring Instruments by Yixin Ma 27/02/2013 Contents 1. Functional Elements of an Instrument 2. Active and Passive Transducers 3. Analog and Digital Modes of Operation 4. Null and Deflection Methods 5. Input-Output Configuration of Instruments and Measurement Systems 6. Methods of Correction for Interfering and Modifying Inputs 7. Conclusions
上海充通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Measured Quantity Measured Primary Medium Sensing (Energy) Element It first receives energy from the measured medium and produces an output depending in some way on the measured quantity ("measurand") Functional Elements in an Instrument 上游文通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Measured Quantity Measured Primary Variable Medium Sensing Conversion (Energy) Element Element For instrument to perform the desired function,this element converses the physical variable from the Primary Sensing Element to a more suitable variable while preserving the information content. Functional Elements in an Instrument
2.1 Functional Elements of an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy) Functional Elements in an Instrument It first receives energy from the measured medium and produces an output depending in some way on the measured quantity (“measurand”) 2.1 Functional Elements of an Instrument Variable Conversion Element Functional Elements in an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy) For instrument to perform the desired function, this element converses the physical variable from the Primary Sensing Element to a more suitable variable while preserving the information content
上游文通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Measured Quantity Measured Primary Variable Variable Medium Sensing Conversion Manipulation (Energy) Element Element Element Manipulation means specifically a change in numerical value according to some definite rule but a preservation of the physical- nature of the variable. e.g.,an electronic amplifier Functional Elements in an Instrument 上游文通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Measured Quantity Measured Primary Variable Variable Data Medium Sensing Conversion > Manipulation Transmission (Energy) Element Element Element Element This element is used to transfer data in between physically separated elements Functional Elements in an Instrument
2.1 Functional Elements of an Instrument Variable Conversion Element Variable Manipulation Element Functional Elements in an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy) Manipulation means specifically a change in numerical value according to some definite rule but a preservation of the physical nature of the variable. e.g. , an electronic amplifier 2.1 Functional Elements of an Instrument Variable Conversion Element Variable Manipulation Element Data Transmission Element Functional Elements in an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy) This element is used to transfer data in between physically separated elements
上游文通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Measured Quantity Measured Primary Variable Variable Data Medium Sensing Conversion Manipulation Transmission (Energy) Element Element Element Element Data Presentation Element to put the information into a Presented Data form that Observer recognizable by one of human senses Functional Elements in an Instrument 上游文通大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument Interface Measured Quantity Measured Primary Variable Variable Data Medium 1 Sensing Conversion Manipulation Transmission (Energy) Element Element Element Element 业 Data Data Presentation Storage/Playback Element Element Presented Data Interface Control Observer System Functional Elements in an Instrument
2.1 Functional Elements of an Instrument Variable Conversion Element Variable Manipulation Element Data Transmission Element Data Presentation Element Observer Presented Data Functional Elements in an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy) to put the information into a form that recognizable by one of human senses 2.1 Functional Elements of an Instrument Variable Conversion Element Variable Manipulation Element Data Transmission Element Data Storage/Playback Element Data Presentation Element Observer Control System Presented Data Interface Interface Functional Elements in an Instrument Measured Quantity Primary Sensing Element Measured Medium (Energy)
上海充通大学 2.1 Functional Elements of an Instrument SHANGHAI JIAO TONG UNIVERSITY DRAN Backlight LCD Core and lo Powe REF Current t Shunts MS to D onvert wer Management ted AC/DC Supply AC Line Schematics of a DMM from TI LEGEND ■Logi (DMM Digital Multi-Meter) http://focus.ti.com/cn/docs/solution/folders/print/593.html cks 上海充大学 SHANGHAI JIAO TONG UNIVERSITY 2.1 Functional Elements of an Instrument spring,variable conversion Pointer scale, data presentation linkage, data manipulation Piston rod,data transmission Piston,sensing variable conversion Measured medium Fig.2.2 Pressure Gage
2.1 Functional Elements of an Instrument Schematics of a DMM from TI (DMM = Digital Multi-Meter) http://focus.ti.com/cn/docs/solution/folders/print/593.html 2.1 Functional Elements of an Instrument Fig. 2.2 Pressure Gage Measured medium Piston, sensing + variable conversion Piston rod, data transmission spring, variable conversion linkage, data manipulation Pointer + scale, data presentation