National Instruments 781425-01 CompactDAQ Chassis

The National Instruments 781425-01, also known as the cDAQ-91671, is a USB CompactDAQ chassis with one slot that is powered by a bus and intended for tiny, portable sensor measurement systems. This chassis uses USB's plug-and-play ease of use to integrate seamlessly with electrical measurement and sensor chores. It is an important component of building flexible measuring systems because it controls the synchronization, timing, and data flow between C Series I/O modules and an external host.

Users can mix and match analog, digital, and counter/timer measurements as needed with the 781425-01 chassis, which supports a variety of C Series I/O modules. It is suitable for a wide range of applications because to its flexibility, from simple data collection to intricate automated test settings. It is suited for quadrature encoders, PWM, event counting, pulse train creation, and period or frequency measurement. It has four 32-bit general-purpose counters/timers that can be accessed via an inserted, hardware-timed digital C Series module.

The installed C Series module determines the maximum sample rate for analog input, with the chassis having an input FIFO capacity of 127 samples. It provides timing resolution of 12.5 ns and timing accuracy of 50 ppm of the sample rate. Depending on whatever C Series module is being utilized, a different number of channels may be supported.

With 16 channels for onboard regeneration, the maximum update rate of 1.6 MS/s (multi-channel, aggregate) can be achieved with analog output capabilities. The selected C Series module determines non-regeneration and hardware-timed jobs as well, with timing precision and resolution matching the requirements for analog input.

Measurements for edge counting, pulse, semi-period, period, two-edge separation, and pulse width counter are supported by the 781425-01 chassis. Position measurements consist of two-pulse encoding and quadrature encoding of X1, X2, and X4 with Channel Z reloading. Applications for output include equivalent time sampling, frequency division, pulse and pulse train with dynamic updates.