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PCI DAQ boards offer various levels of flexibility and feature-sets, usually based on price. Some of the more-exotic features include synchronous I/O, support for a large selection of signal-conditioning and channel-expansion options, DMA bus mastering (for continuous data transfer without consuming valuable CPU time), support for multiple PCI boards in one PC, and 100% digital calibration.
Also look for extensive software support -- the vendor's own software programs usually won't be enough in the real world of data acquisition. Such cross-vendor software includes: VisualBasic, C/C++, ActiveX/COM. LabVIEW, DASYLab, MATLAB, and Linux.
Typical Board Specifications
Block View Diagram of Typical PCI DAQ Board
Synchronous I/O for High-Speed Applications — the ability to make analog measurements, read digital inputs, and read counter inputs, while synchronously generating two (and perhaps more) analog outputs. Some DAQ boards require CPU interaction to access I/O other than analog input, making it difficult to generate time-critical analog waveforms. top of page
Signal Input/Output — Some boards, like those from IOTech, simplify I/O by using only one cable and utilizing a single PCI slot. The latching-pin I/O connector contains all analog input channels plus digital I/O lines, counter inputs, timer outputs and analog outputs. top of page
Input — Example: a 16-bit A/D on a DAQ board will be coupled with 16 single-ended,
or 8 differential analog inputs. Look for multiple software-programmable
ranges which provide, e.g., ±10V to ±156mV full-scale. Each
channel should allow software-configurability for a different range,
as well as for single-ended or differential bipolar input.
Bus Mastering — Some pricier boards support bus mastering DMA (direct memory access) which allows
analog and digital/counter input data, as well as analog/digital output
data to flow between the PC and the DAQ board without consuming valuable
CPU time. The drivers supplied with these DAQ boards, as well as other
third-party software support including MATLAB, LabVIEW and DASYLab automatically
utilize bus mastering to efficiently perform I/O from the PC to the DAQ
Updated: Tuesday, March 3, 2020 22:56 PST