Recognizing the diversity of measurement applications, National Instruments approaches data acquisition independent of specific PC bus technologies. You can use the same NI-DAQmx API for communicating across PCI, PCI Express, PXI, PXI Express, USB, Ethernet, and Wi-Fi. Because each of these buses has different portability, throughput, and latency capabilities, NI signal streaming technology abstracts the complexity of programming these different architectures from the user. For example, NI signal streaming overcomes the lower throughput and higher latency associated with USB transfers to make bidirectional waveform streaming possible for a cabled USB DAQ device.
Figure 4. NI signal streaming for NI USB DAQ devices includes custom hardware and software interfaces for streaming continuous, bidirectional waveform data across the bus.
The same technology developed for USB is replicated across other instrumentation buses as well, including Ethernet and IEEE 802.11 (Wi-Fi). The result is that you can repurpose an application developed for a PCI DAQ device (even a high-speed application) to instead use a USB or wireless DAQ device without making any changes to the software. Thus, National Instruments DAQ performance is independent of the particular bus in use.