National Instruments cDAQ

National Instruments CompactDAQ, commonly called cDAQ, is a modular data acquisition family for bringing different sensor measurements into one coordinated system. Rather than dedicating separate instruments to temperature, vibration, strain, and voltage, engineers install compatible C Series I/O modules in a shared chassis. This architecture supports laboratory validation, production testing, structural monitoring, and portable troubleshooting while allowing measurement capabilities to change as projects evolve.

The cDAQ-917x USB lineup includes the single-slot cDAQ-9171, four-slot cDAQ-9174, eight-slot cDAQ-9178, and fourteen-slot cDAQ-9179. The cDAQ-9174 is identified by part number 781157-01, while the cDAQ-9178 uses 781156-01. The cDAQ-9179 adds USB 3.0 connectivity for larger configurations. Chassis such as the cDAQ-9174 and cDAQ-9178 incorporate four 32-bit counters/timers, although access and supported operations depend on the installed modules and available terminals.

For distributed measurements, the cDAQ-918x Ethernet lineup moves acquisition hardware closer to sensors while maintaining a network connection to the host computer. The four-slot cDAQ-9185 and eight-slot cDAQ-9189 support Time-Sensitive Networking, including IEEE 802.1AS synchronization, and provide dual Ethernet ports for daisy-chain connections. These features help coordinate measurements across compatible chassis. Legacy wireless configurations include the single-slot cDAQ-9191, which supports Ethernet and Wi-Fi.

C Series modules determine the measurement capabilities. The NI-9213 provides sixteen thermocouple inputs with cold-junction compensation and open-thermocouple detection. For dynamic measurements, the NI-9234 offers four simultaneous sound and vibration inputs at up to 51.2 kS/s per channel with selectable IEPE excitation. The NI-9237 supports bridge-based strain and load measurements, while the NI-9205 handles general-purpose voltage acquisition. Analog output and digital I/O modules extend a system beyond input measurements.

CompactDAQ chassis coordinate timing and data transfer, but ordinary USB and Ethernet models require an external host to run acquisition software. Legacy cDAQ-913x controllers, including the cDAQ-9139, instead combine processing, storage, and module slots for standalone operation. These controllers should not be confused with CompactRIO systems, which provide a user-programmable FPGA for customized timing, processing, and control.

Software selection is equally important. NI-DAQmx supports acquisition development in compatible LabVIEW and other programming environments, while FlexLogger offers configuration-based data logging for supported hardware. Before replacing or expanding equipment, verify the chassis, module, driver, operating system, and application versions together. Sharing the C Series form factor does not guarantee compatibility.

Select modules by sensor type, channel count, input range, isolation, and required sample rate. A chassis slot count describes module capacity, not measurement channels, and total system throughput also depends on the selected modules, connection bandwidth, and host computer performance.

Apex Waves helps customers source CompactDAQ hardware for established test systems and replacement requirements. Match the exact model and part number, then review module compatibility, connections, power requirements, and calibration needs before ordering.