Understanding the Unique Requirements of Portable Data Acquisition Systems Print E-mail
Nov 01 2007
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In addition to withstanding extreme temperatures, portable data acquisition units need to be able to survive in high shock and vibration environments such as the trunk of a car or onboard an airplane, or simply as a result of human mishaps such as being dropped by its user. Also inherent in environments such as these, is the requirement for the portable data acquisition system to be as compact and lightweight as possible.

Further packaging constraints, such as watertight housing, need to be considered for applications such as seismic exploration in which data acquisition systems are required to make deep underwater measurements at levels ranging from 300m to 1500m below sea level. Sealed data acquisition systems used for oceanographic research need to be capable of continuous recording of low-frequency seismic signals and storage of the data in a mass memory while being reliable, effective, and economical.

Accuracy and Sampling Speed

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Off-shore oil rigs present one of the harshest environments for portable data acquisition systems.

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An obvious characteristic of any data acquisition system is the need to accurately capture recorded data. While most would assume that this is a given, the degrees of accuracy attainable by portable data acquisition units available on the market today can vary considerably. Invariably, the accuracy of field measurements is highly dependent upon the sensors being used. For most sensors that have been calibrated in the laboratory and installed in the field, accuracies in the range of 0.01 % to 1 % of full scale are typical. Some sensors are significantly less accurate. For example, strain gauges commonly used for strain and stress measurements depend on the installation material for their accuracy and can have field accuracies ranging from 3% to 5% of full scale.



 

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