data-acquisition.us

[daqmaster]

Data-acquisition (or DAQ) systems measure, store, display, and analyze information gathered from myriad devices. The vast majority of measurements (aka metrics) require a transducer or a sensor, a device which can convert measurable physical quantity into an electrical signal. E.g.: temperature, strain, acceleration, pressure, vibration, and sound. Other examples are humidity, flow, level, velocity, charge, pH, and chemical composition.

Sensors come in numerous shapes, sizes, and specifications. They connect between the measured physical device and the signal conditioner’s input. Most sensors may be purchased “off-the-shelf”, however some applications demand they be custom-made specifically for particular measurement requirements. Irrespective of input, however, the output signal is usually a voltage, current, charge, or resistance and all can be conditioned and handled equally well. Component manufacturers often provide specifications, application notes, and principles of operation for their specific sensor to help users apply the device in the most efficient way.


Signal conditioners accept sensor output signals and convert them into a form which DAQ systems can manipulate. Signal conditioners normally amplify, filter, isolate, and linearize these signals. They also convert current to voltage and voltage to frequency, provide other functions such as simultaneous sample and hold (SS&H), and supply a bias voltage or signal excitation for certain transducers. They might come with single-ended inputs or differential inputs for improving signal-to-noise ratios. The output of the signal conditioner, in turn, connects to the input of an analog-to-digital converter (ADC) embedded within the data acquisition (DAQ) system. Finally, the ADC converts the conditioned analog signal to a digital signal that can be transferred out of the data acquisition (DAQ) system to a computer (PC) for processing, graphing, and storing.