Definitions:
Dato: symbolic representation (numerical, alphabetical …), attribute or characteristic of a value. There is no sense in itself, but properly treated (processed) can be used in calculations of the relationship or making decisions.
Acquisition: Collection of a set of physical variables, voltage conversion and digitization in a form that can be processed in a computer.
System: A group organized devices that interact with each other by offering more comprehensive benefits and the highest level. Once the electrical signals are converted to digital, are sent through the data bus to the memory of the PC. Once the data is in memory can be processed with an appropriate file to your hard disk, displayed on the screen, etc …
Bit resolution: Number of bits that the analog to digital converter (ADC) used to represent a signal.
Range: minimum and maximum values between which the sensor, instrument or device operating under specifications.
Nyquist Theorem: When sampling a signal, the sampling frequency must be greater than twice the bandwidth of the input signal, to reconstruct the original signal exactly from its samples. Otherwise, the Aliasing phenomenon that occurs at below-sampled. If the signal suffers from aliasing, it is impossible to recover the original. Recommended Sampling Rate:
‘2 Frequency (measuring frequency)
’10 Frequency (detail of the waveform)
The components of data acquisition systems, with appropriate sensors that convert any measurement parameter to an electrical signal, which was acquired by the data acquisition hardware. The acquired data are displayed, analyzed and stored in a computer, either using vendor supplied software or other software. The controls and displays can be developed using various programming languages such as general purpose VisualBasic, C, Fortran, Java, Lisp, Pascal. Specialized programming language used for data acquisition include EPICS used in the construction of large systems of data acquisition, LabVIEW, which provides a graphical programming environment optimized for data acquisition and MATLAB. These environments provide acquisition of a programming language as well as libraries and tools for data acquisition and subsequent analysis.
In the same way that it takes an electrical signal and is converted into a digital computer to send, you can also take a digital or binary signal and convert it into an electric. In this case the element which makes the processing card or module is a data acquisition output, or control card. The signal within the memory of the computer generates an appropriate program to the applications that the user wants and then to process it, is received by mechanisms that are running mechanical movement, through servomechanisms, which are also the type transducers.
A typical acquisition system uses sensors, transducers, amplifiers, converters – digital (A / D) and digital – analog (D / A), to process information about a physical system so digitized.
How acquired data ‘ data acquisition starts with the physical phenomenon or physical property of an object (under investigation) to be measured. This property or physical phenomenon could be the change in temperature or the temperature 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 these different properties or phenomena.
A transducer is a device that converts a physical property or phenomenon into an electrical signal corresponding measurable, such as voltage, current, change in the values of resistance or capacitor, etc.. The ability of a data acquisition system to measure different phenomena depends on the transducer to convert the signals of physical phenomena measurable in the data acquisition hardware. Transducers are synonymous with sensors to DAQ systems. There are specific transducers for different applications such as measuring temperature, pressure, or fluid flow. DAQ also displays a variety of signal conditioning techniques to modify appropriately different voltage electrical signal, which can then be digitized using CED.
The signals may be digital (also called the logic signals) or analog depending on the transducer used.
The signal conditioning suelee be necessary if the signal from the transducer is not suitable for the DAQ hardware is used.
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