70/LM-0088 - AUTOMATIC MEASUREMENT SYSTEMS
Academic Year 2017/2018
Free text for the University
PAOLO ATTILIO PEGORARO (Tit.)
- Teaching style
- Lingua Insegnamento
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The course “Automatic Measurement Systems” is designed to provide first year students of the “Laurea Magistrale” Degree in Electronic Engineering (Bachelor graduated students) with a deeper understanding of measurement area, with specific attention to advanced measurement technologies, methodologies and measurement signals processing concerning electrical quantities.
The Course aims at providing comprehensive knowledge of hardware and software useful for designing and using automatic measurement systems for industrial applications.
In details, the aims can be presented by the following five descriptors:
- Knowledge and understanding
Deep knowledge and understanding of theoretical and applicative topics in the field of industrial and automatic measurement systems. Knowledge of devices and techniques to design and implement an automatic measurement system.
- Applying knowledge and understanding
Ability to design and manage complex automatic measurement systems, by choosing devices that are most suitable both from a technical and economical point of view. Ability to integrate advanced measurement techniques with industrial level devices.
- Making informed judgements and choices:
Ability to evaluate results, select relevant information and suitable approximations to realize measurement systems. The student must test her/his capability to perform design choices and justify them.
Capability to communicate technical information both orally and in writing. Ability to present and justify design choices. Ability to discuss problems and solutions with specialists and non-specialists. Anility to be either synthetic or accurate depending on the context.
-Continuous learning skills
Capability of continuous learning, through the proper interpretation of scientific and technical literature, manuals of manufacturers and technical standards.
The prerequisites are those indicated in the regulations of the "Laurea Magistrale in Ingegenria Elettronica" for admission to the first year.
Basic knowledge of electronics and conventional instrumentation for electrical quantities
Knowledge of the fundamental measuring methods and uncertainty evaluation and propagation.
Introduction(4 hours -lessons)
Course presentation (expected skills, examination guidelines, reference materials).
Digital measurement system, components and performance.
Noise and other interference signals.
Measurements in industrial environment(6 hours - lessons)
Working principles of most important industrial sensors and transducers.
Temperature sensors and corresponding conditioning systems.
Wheatstone bridge for resistance measurement.
Automatic measurement systems: concepts.
Microprocessor based measurement systems(8 hours - lessons)
Data acquisition systems with analog and digital I/O. Available commercial products.
A/D e D/A converters.
Systems for real-time measurement.
Automatic test systems.
Remote control of measurement devices (10 hours – lessons)
Distributed measurement systems and large-scale architectures.
Communication systems, serial and parallel buses.
Main standards for interfacing measurement instrumentation.
Synchronization problems and methods.
Digital processing (12 hours – lessons)
Digital processing of measured signals.
Outline of theory and problems of Fourier Analysis. Discrete Fourier Transform (DFT and FFT)
Aliasing and leakage reduction techniques. Smoothing windows.
Digital filters: theory and design.
Amplitude, phase and frequency measurements for sinusoidal signals. Interpolated DFT.
Virtual instrumentation and automatic measurement systems design – Laboratory(20 hours – laboratory)
The LabVIEW graphic environment.
Development of Virtual Instruments (VIs) and SubVIs for signal processing.
Laboratory experience on data acquisition and elaboration with modular and general purpose devices.
Digital filters implementation.
Programs and prototypes for synchronized measurements.
Laboratory experience for automatic measurement system design and simulation, scheduled to be faced also by students grouped by 2 to 3.
Ph.D students' and/or industry people's lectures.
The course is composed of 40 hours of theory lessons and 20 hours of practice, for a total of 60 hours. During the theory lessons, the teacher sets out the topics in the program; whereas during the practice sessions, students, working in small groups under the supervision of the teacher, learn how to design and implement using the techniques of virtual instrumentation their own solution to an assigned measurement project (for instance, the synchronized measurements of amplitude, phase angle and frequency of a sinusoidal signal with dynamic parameters).
Verification of learning
The examinations are carried out in two stages.
Students have to develop, in a team of up to three people, a project (an example of Automatic Measurement System in LabVIEW environment) on a topic covered during the course. A report on the laboratory activity is required. A discussion on the project and on theoretical issues is also required.
During the lessons (laboratory lessons), the aims of the project, related international standards and laws, methods and results of validation tests are discussed.
The report, together with the project code, must be sent to the professor before the second stage.
The final exam (second stage) consists in an oral exam aimed at discussing the report and the project outcomes and at verifying the preparation of the student in other topics included in the course.
The final mark to pass the exam ranges from 18/30 to 30/30. The final evaluation considers both the stages and maximum 15 points are for the first one and maximum 15 points for the second one, which are summed to define the final mark. The evaluation rewards student’s autonomy during project, capability to rethink the theoretical lessons in applications, defend personal choices and strategies in the project, communicate clearly acquired information.
In this regard, the questions of the oral are organized to highlight the following aspects:
- Acquired knowledge of theoretical topics
- The applied knowledge and understanding, with particular attentio to practical cases
- The capacity to apply methods and to make judgements on the obtained results, with particular attention to the achieved accuracy of the automatic measurement system designed for the project.
Teaching material provided during the course.
This is the reference material covering all the topics and aspects.
Useful book on digital signal processing, DFT, Zeta Transform, digital filters:
A. V. Oppenheim, R. W. Schafer: "Discrete-Time Signal Processing", Pearson, 2009.
or its su previous editions or versions.
Other textbooks for supporto and/or deeper learning:
AA. VV.: “Phasor Measurement Units and Wide Area Monitoring Systems”, Eds. C. Muscas, A. Monti, F. Ponci, Academic Press, 2016. (Synchronization methods and Amplitude, phase and frequency measurements for sinusoidal signals. Support to the project.)
Keithley Instruments: Data acquisition and control handbook, 2001. (Measurements in industrial environment and Microprocessor based measurement systems)
The teacher provides the slides used for the presentation of lessons in electronic format.
Datasheets of measurement devices and international standards are also presented and discussed.