data-acquisition.us

[daqmaster]

Data Acquisition (DAQ) technology provides the link between data-generating sensors and data-storing recording devices. DAQ can also provide the means for driving external actuators from a computer, via the generation of external signaling. DAQ technology includes both hardware and software.

Through modern microprocessor technology, low-cost personal computers are now the most important (and most common) carrier for data acquisition cards. High clock speeds of modern central processing units (CPUs), such as Pentium and PowerPC, allow higher sampling rates. This, along with high-performance bus architectures such as PCI, inexpensive RAM, and fast high-capacity hard disks make long-term continuous measurements possible.

In the past, the clock speed of the computer CPU significantly affected the performance of the DAQ system. However, modern direct memory access (DMA) transfer technology quickens the pace of the system by using dedicated hardware to transfer data directly into system memory. Hence, the CPU is not bogged down with moving data and is therefore free to engage in more complex processing tasks. Also, if an application requires real-time processing of high-frequency signals, a dedicated digital signal processing (DSP) chip can be built-in on the DAQ board to share the work load of the main processor.

Another important development is portable data acquisition, based on laptop computers with PCMCIA cards. This configuration allows more convenient in-the-field measurements that used to be cumbersome for practicing engineers.

Newer broadband Internet and broadband cellular phones outperform traditional modem hookups using RS-232 or RS-485 serial communication ports. These emerging communication technologies will allow faster, better and cheaper remote monitoring and access measurements.

In summary, today's level of data acquisition technology, although still not perfect, is far more effective and efficient than a decade ago. In the future, one can expect even more affordable and accurate measurement instruments, some that could be fitted into computers as small as modern hand-held calculators , personal digital assistants or even mobile phones.