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Data Acquisition and Instrumentation
Acquisition of useful data from sensors is accomplished by electronic instrumentation called data acquisition (DAQ) systems (DASs). They are often combined with analog and digital output capabilities as data acquisition or instrumentation and control systems. This series of articles is a tutorial presentation of principles of instrumentation that is typically multi-channel, medium to high resolution (12 to 20 bits) and relatively slow – slower than oscilloscopes in sample rate. DAQ principles – mostly basic, with some subtleties and simplifying concepts – and sensors will be emphasized.
To give the presentation a concrete context, the application example will be a rocket test system as used to verify the performance of small rockets fired statically on test stands. Test firings must be sequenced by a controller and a DAS acquires the sensor data. The rocket test control system must be informed about what is going on in the rocket, and the instrumentation subsystem provides it. Sensors convert quantities of interest, such as pressure or acceleration, to electrical form. The data acquisition system converts these electrical quantities, in order, to a digital form compatible with the control computer, as its input. In all but very simple rockets, a separate instrumentation computer will process the sensor information into a useable form. This is the instrumentation system of the rocket test stand.
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