R Series Application - Custom Data Acquisition

A typical data acquisition device has fixed timing, triggering, and synchronization options built into high-level driver VIs, such as NI-DAQmx. While these devices address the majority of data acquisition applications, some applications have specific requirements that these fixed functions cannot meet. NI R Series multifunction RIO data acquisition devices feature a dedicated analog-to-digital converter (ADC) and digital-to-analog converter (DAC) per channel. This combination of integrated I/O and field-programmable gate array (FPGA) technology offers specialized functionality such as multirate sampling, individual channel triggering, and high-speed onboard decision making, which are outside the capabilities of typical data acquisition hardware. Your NI LabVIEW code executes in the hardware on the FPGA, giving you direct, immediate control over all the I/O signals. This functionality makes R Series devices particularly useful in applications requiring flexible encoder interfaces, pulse-width modulation (PWM) communication, or custom counters.

Example - Implementing a Custom Start Trigger

In many cases, applications have unique timing or triggering requirements. The example in the figure implements a custom analog input start trigger based off three rising edges on a digital line. The first frame in the sequence continually loops and reads from DIO0 at 40 MHz. The shift registers hold a count that is incremented with every rising edge on DIO0. After the count has surpassed the amount in the threshold control, the loop is stopped and the next frame of the sequence is executed to perform the analog input.

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Custom Three-Pulse Start Trigger Implemented in LabVIEW FPGA

A typical data acquisition device likely does not have three-pulse start trigger functionality built into the high-level driver VIs. Additionally, a processor-based host machine cannot implement custom triggering functionality with hardware determinism. Using an R Series device, on the other hand, you can compile and implement code on the FPGA with hardware determinism. The FPGA provides the ultimate timing and triggering flexibility for data acquisition applications.

Custom Data Acquisition Resource Kit

For detailed information on implementing custom data acquisition with R Series devices, download the following resource kit which includes tutorials, case studies, and webcasts.

Download the Resource Kit

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