DATA ACQUISITION

'Data acquisition' is the sampling of the real world to generate data that can be manipulated by a computer. Sometimes abbreviated 'DAQ' or 'DAS', data acquisition typically involves acquisition of signals and waveforms and processing the signals to obtain desired information. The components of data acquisition systems include appropriate sensors that convert any measurement parameter to an electrical signal, which is acquired by data acquisition hardware.
Acquired data is displayed, analyzed, and stored on a computer, either using vendor supplied software, or custom displays and control can be developed using various text-based programming languages such as BASIC, C, Fortran, Java, Lisp, Pascal. EPICS is used to build large scale data acquisition systems.
Comedi is an open source project that defines a application programming interface and driver structure. It is a standard programming method to access data acquisition hardware. LabVIEW offers a graphical programming environment optimized for data acquisition. MATLAB provides a programming language but also built-in graphical tools and libraries for data acquisition and analysis.

Contents

How data is acquired

History

See also

References

Books on data acquisition

Articles on data acquisition

Articles about generic data acquisition systems

Articles about how to teach a course on data acquisition

Articles about data acquisition systems for specific applications

External links

How data is acquired

'Data acquisition' begins with the physical phenomenon or physical property of an object (under investigation) to be measured. This physical property or phenomenon could be the temperature or temperature change of a room, the intensity or intensity change of a light source, the pressure inside a chamber, the force applied to an object, or many other things. An effective 'data acquisition' system can measure all of these different properties or phenomena.
A 'transducer' is a device that converts a physical property or phenomenon into a corresponding measurable electrical signal, such as voltage or current. The ability of a 'data acquisition' system to measure different phenomena depends on the transducers to convert the physical phenomena into signals measurable by the data acquisition hardware. Transducers are synonymous with sensors in DAQ systems. There are specific 'transducers' for many different applications, such as measuring temperature, pressure, or fluid flow.
'Signals' may be digital (also called 'logic signals' sometimes) or analog depending on the tranducer used.
'Signal conditioning' may be necessary if the signal from the transducer is not suitable for the DAQ hardware to be used. The signal may be amplified or deamplified, or may require filtering.
'DAQ hardware' is what usually interfaces between the signal and a PC. It could be in the form of modules that can be connected to the computer's ports (parallel, serial, USB, etc...) or cards connected to slots (PCI, ISA) in the mother board.
DAQ-cards often contain multiple components (multiplexer, ADC, DAC, TTL-IO, high speed timers, RAM).
These are accessible via a bus by a micro controller, which can run small programs.
The controller is more flexible than a hard wired logic,
yet cheaper than a CPU so that it is allright to block it with simple polling loops.
For example:
Waiting for a trigger, starting the ADC, looking up the time, waiting for the ADC to finish,
move value to RAM,
switch multiplexer,
get TTL input,
let DAC proceed with voltage ramp.
'Driver software' that usually comes with the DAQ hardware or from other vendors, allows the operating system to recognize the DAQ hardware and programs to access the signals being read by the DAQ hardware.

History

Scientific Solutions -->link Scientific Solutions invented the PC based data acquisition in 1981 with the introduction of the 'LabMaster', 'BaseBoard','DADIO','LabTender', 'IEEE-488' hardware and 'LabPac' software. Scientific Solutions was formally a part of Tecmar.
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See also

★ Signal processing

★ Data acquisition system

★ Data analysis

★ Test method

★ Input devices:

★
★ 3D scanner

★
★ Analog to digital converter

★
★ Time to digital converter

★ Hardware:

★
★ CAMAC

★
★ Industrial Ethernet

★
★ Industrial USB

★
★ NIM

★
★ PXI

★
★ VMEbus

★
★ VXI

★ Software:

★
★ Comedi

★
★ EPICS

★
★ DASYLab

★
★ LabVIEW

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★ MATLAB

★
★ ATEasy

References

1. COMDEX FALL 1981, BYTE VOL7 NO.1
2. PC Magazine Vol1 No.1
3. PC World Issue1 No.1
4. PC TechJournal, Vol1 No.1
5. Test&Meausrement World Vol11 No 10 Decade of Progress Award: Scientific Solutions - LabMaster

Books on data acquisition

★ Digital Design for Computer Data Acquisition, Charles D. Spencer, , , Cambridge University Press, 1990, ISBN 0-521-37199-6

★ IBM-PC in the laboratory, B.G. Thompson & A. F. Kuckes, , , Cambridge University Press, 1989, ISBN 0-521-32199-9

★ Techniques for Nuclear and Particle Physics Experiments, W. R. Leo, , , Springer, 1994, ISBN 3-540-57280-5

Articles on data acquisition

Articles about generic data acquisition systems

★ Ethernet based list processing controller for high speed data acquisition systems, , , E. T. Subramaniam, Kusum Rani, B. P. Ajith Kumar, and R. K. Bhowmik, Review of Scientific Instruments,

★ An FPGA-based general-purpose data acquisition controller, , , Robson CCW, Bousselham A, Bohm C, IEEE Transactions on Nuclear Science,

★ Serial port controls 16 independent output lines, , , Xia YP, Electronics World,

★ A handheld data acquisition system for use in an undergraduate data acquisition course, , , Mason G, IEEE Transactions on Education,

★ A Universal Serial Bus interface for electronics projects and instruments, , , Fullem TZ, Spencer CD, American journal of physics,

★ A capable voltage logger for the PCI bus, , , Spencer CD, American journal of physics,

Articles about how to teach a course on data acquisition

★ Teaching data acquisition - An undergraduate experiment in the advanced analytical chemistry laboratory, , , Antler M, Salin E, Wilczek-Vera G, Journal of Chemical Education,

★ Graphical computing in the undergraduate laboratory: Teaching and interfacing with LabVIEW, , , Moriarty PJ, Gallagher BL, Mellor CJ, Baines RR, American Journal of Physics,

★ A course in computer-based data acquisition, , , Hubin WN, American Journal of Physics,

★ A computer-based data acquisition laboratory for undergraduates, , , J. Maps, American Journal of Physics,

★ A laboratory course in computer interfacing and instrumentation, , , Carl A. Kocher, American Journal of Physics,

★ Two freshman courses which introduce digital electronics, programming, computers, and interfacing, , , Seligmann P, Spencer CD, American Journal of Physics,

Articles about data acquisition systems for specific applications

★ A Portable Acquisition System Based on USB Standard for the Medipix2 X-Ray Detector, , , Fanti, V. Marzeddu, R. Piredda, G. Randaccio, P., IEEE Transactions on Nuclear Science,

★ Synchronous analog I/O for acquisition of chaotic data in periodically driven systems, , , DeSerio R, American journal of physics,

★ The computer mouse as a data acquisition interface: Application to harmonic oscillators, , , Ochoa OR, Kolp NF, American Journal of Physics,

★ Hardware and software for a pulse height analyzer linked to a personal computer, , , Spencer CD, Paul SR, Computers in Physics,

External links

★ Midas PSI GPLed DAQ software used in particle and nuclear experiments.

★ COMEDI Project developing open-source drivers, tools, and libraries for data acquisition