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Last update: OPEKAR (29.01.2003)
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Last update: OPEKAR (31.01.2003)
1. R.Kalvoda, Použití operačních zesilovačů v chemické instrumentaci, SNTL, Praha 1974.
2. H.V.Malmstadt, C.G.Enke, S.R.Crouch, Microcomputer and Electronic Instrumentation; Making the Right Connections, ACS, Washington, DC, 1994.
3. L.K.Wells, J. Travis, LabView for Everyone, Prentice-Hall PTR, New Jersey 1997. |
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Last update: prof. RNDr. František Opekar, CSc. (03.11.2011)
Předmět je zakončen předložením vypracovaných protokolů z jednotlivých probíraných témat a jejich diskusí. |
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Last update: OPEKAR (29.01.2003)
1. Introduction - definition of the problem.
General scheme of a measuring device (sensor - transducer - display) or a regulator (required value - actuator). Computer as a universal measuring device and its position in a measuring train: interface - cpu - software.
2. General information.
Classification of electric signals/information for measuring purposes (A-analog domain, T-time domain, D-digital domain, P-physical, non-electrical, form of information). Inter-domain conversion of the signals, D/A, A/D converters.
3. Computer functioning as a measuring device.
3.1 Introduction to LabView programming, virtual instrumentation.
Opening and closing of the program; the first instrument composed of "voltage source" and "voltmeter", start and stop of the program application (simple run, continuous run); change of the measuring range; data format; data modification by in-built functions or one's own expressions; indication of the satisfied conditions; some tools for debugging of the virtual device program application; saving of the application;
Principles of timing, time loop; effect of timing on the signal displaying; saving data into file and their off-line processing by a spreadsheet program.
3.2 Introduction to LabView programming, interconnection of the virtual device with a real word.
Output of the voltage signal from the computer to external device; on-line measuring and processing of the external voltage signal by computer; creating an application turning the computer into the universal measuring device (which is used for all next measurements).
4. Signal modification before its processing by a computer.
Operational amplifier (OA) - a fundamental component for processing of analog signals: description (non-inverting and inverting input, output, power supply, compensation elements); basic properties (gain, input and output impedance, effect of the input and feedback resistors, saturation voltage); laboratory kits with OA - a simple realisation of electronic analog circuits (description of the kit and its modules).
5. Common analog circuits used for signal modification.
5.1 Inverting amplifier of voltage: measuring of the dependence of the output voltage on the input voltage for different feedback resistors; comparison of the results with theoretical values; determination of saturation voltage; graphical processing of the results.
5.2 Current follower: principles of right measuring of current; comparison of the theoretical and practical dependence of the output voltage on the input current at various feedback resistors; graphical processing of the results; the graphical record of the current flowing through the phototube at different light intensity.
5.3 Voltage follower: principles of right measuring of voltage; test of the importance of the source - voltage impedance adjustment (proper voltmeter choice); pH measurement using a glass electrode (computer is programmed to pH-meter); analog and digital signal filtration.
5.4 Non-inverting voltage amplifier: Theoretical derivation of the relationship between output and input voltage and confirmation of the result by experiment.
6. Voltage and current sources realized using an OA.
Square and triangle wave generator: assembly of the generator, testing its properties, change of the frequency.
Galvanostat: test of the galvanostat based on a non-inverting OA; determination of the dependence of a current on a load resistance, limits of proper functioning.
Potentiostat: test of the potentiostat based on a inverting OA; determination of the dependence of a controlled potential on a load resistance, limits of proper functioning.
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