Data Acquisition

3PC based data acquisition (DAQ) systems and plug-in boards are used in a wide range ofapplications. Typically, general-purpose DAQ plug-in boards are used for measuring analogand digital input and output voltages.As we have seen, many transducers’ signals must be conditioned in some way before aDAQ board or measuring system can accurately acquire the desired signal. Signal conditioningis the term generally used to describe the front end pre-processing required toconvert the electrical signals received from transducers into signals which DAQ plug-inboards or other forms of data acquisition hardware can accept.In addition, many transducers require excitation currents or voltages, Wheatstonebridge completion and linearization to allow accurate measurement of the required signal.Therefore, most PC based DAQ systems include some form of signal conditioning equipment.The fundamental functions that a signal conditioning equipment performs are:• Amplification• Isolation• Filtering• Excitation• LinearizationThe type of signal conditioning equipment required, and the manner in which this isinterfaced within the DAQ system, is largely dependent on the number and type of transducers,their excitation and earthing requirements, and no less importantly, how far thetransducers are located from the personal computer, which must acquire, analyze andstore the transducer signal data.The signal conditioning functions performed are implemented in different types of signalconditioning products, covering a range of price, performance, modularity and ease ofuse.