USB chassis tips better performance, lower cost

National Instruments has improved the NI CompactDAQ chassis released in 2006 with two new products. The NI cDAQ-9174 four-slot and cDAQ-9178 eight-slot chassis add a four-slot option and the ability to take mixed-sensor measurements at different rates. They feature two built-in, external BNC triggers and four advanced counters. When used with the NI-DAQmx driver and measurement services software for the NI LabVIEW graphical programming and development environment, these two chassis make the NI CompactDAQ system easier to program and more suitable for mixed-signal data acquisition systems.

NI offers more than 50 C series modules to use interchangeably in NI CompactDAQ systems for measurements such as temperature, strain, voltage, current, sound and vibration. The smaller footprint of the cDAQ-9174 saves space and can measure up to 128 channels in a 16cm x 9cm x 9cm system for as low as Rs.1,513.28 ($31) per channel.

With the new cDAQ-9174 and cDAQ-9178 chassis, engineers can sample from NI C series analogue input modules at different rates instead of implementing single-rate sampling in the cDAQ-9172 chassis. This feature makes programming easier because low-speed measurements can be separated from high-speed measurements, eliminating the need to oversample or decimate unwanted data. In addition to simpler software development, the multiple timing engines are optimised for multi-core processing—each driver call to a timing engine can be processed in a separate loop to maximise processing core use and process data more quickly.

The cDAQ-9178 eight-slot chassis features external BNC triggers. With these external triggers, engineers can synchronise an NI CompactDAQ system with an external device or another system without installing and wiring a digital module, making synchronising systems easier and more cost-effective.

Other advancesThe new NI CompactDAQ chassis contain four advanced counters, which is twice the counters available in the cDAQ-9172 chassis. Some counter operations on the original chassis, such as finite pulse train generation, require the use of two counters. With the two new chassis, many of these operations use only a single counter because of counter technology advancements, providing more available counters for additional measurements.

The chassis operate in a temperature range of -20°C to 55°C and can withstand up to 30g shock and 3g vibration. NI CompactDAQ achieves Hi-Speed USB throughput with NI signal streaming technology, so that the chassis can simultaneously perform multiple, high-speed operations such as waveform measurements, generation, digital I/O and counter operations.

Every NI CompactDAQ chassis is shipped with NI LabVIEW SignalExpress LE data-logging software. With USB plug-and-play data acquisition and LabVIEW SignalExpress, engineers can connect NI CompactDAQ to a PC, laptop or netbook and start measuring data within three clicks of a mouse.

For greater flexibility, NI CompactDAQ also includes NI-DAQmx driver and measurement services software for LabVIEW, NI LabWindows(TM)/CVI, C/C++ and Microsoft Visual Studio .NET. Designed for more advanced data-logging features such as alarming, timed logs, analysis and reporting, LabVIEW SignalExpress is a full-featured development environment that works with all devices that run NI-DAQmx including NI CompactDAQ.

Ubiquity and a wide range of application support make Windows a popular operating system for benchtop, portable laptop and production line test systems. NI CompactDAQ is fully compatible with Windows 7, and the latest generation of NI CompactDAQ chassis shows a greater than 10 per cent performance boost for some high-bandwidth streaming applications when compared with the same program run on Windows XP.