NI CompactDAQ Overview

Publish Date: Nov 03, 2014 | 45 Ratings | 3.71 out of 5 |  PDF

Table of Contents

  1. Simple Complete USB Data Acquisition
  2. Flexibility with over 40 Measurement Modules
  3. Complete Data Acquisition
  4. Software Options with NI CompactDAQ
  5. Frequently Asked Questions

1. Simple Complete USB Data Acquisition

NI CompactDAQ provides the plug-and-play simplicity of USB to sensor and electrical measurements on the benchtop, in the field, and on the production line. By combining the ease of use and low cost of a data logger with the performance and flexibility of modular instrumentation, NI CompactDAQ provides fast, accurate measurements in a small, simple, and affordable system.

With the flexible NI software options, you can easily use NI CompactDAQ to log data for simple experiments or to develop a fully automated test or control system. The modular design can measure up to 256 channels of electrical, physical, mechanical, or acoustical signals in a single system. In addition, per-module analog-to-digital converters and individually isolated modules ensure fast, accurate and safe measurements.


Figure 1. NI CompactDAQ packs USB DAQ, signal conditioning, and sensor connectivity for up to 256 channels in a 25 by 9 by 9 cm system.

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2. Flexibility with over 40 Measurement Modules

NI CompactDAQ can measure dynamic signals such as sound, vibration, and pressure at up to 50 kS/s per channel in addition to static signals such as DC voltage and temperature. Other modules provide single-point and waveform output capability at rates up to 100 kS/s/channel, or digital I/O at rates up to 10 MHz. Some of the more recently released modules add measurements such as 5A current input, ±300 Vrms measurement, and 24-bit precision high-speed analog input.

Figure 2. Acquire from different modules at different rates in one single system.

Because NI CompactDAQ is a modular system, further measurement types and channels can be added to the system by simply plugging in additional modules. All modules are hot swappable and autodetect once you insert them into any CompactDAQ chassis. All modules are automatically synchronized when programmed in the same task, and a single NI CompactDAQ system can simultaneously stream high-speed analog input, analog output, digital input, and digital output over a single USB connection.

For a complete list of available modules, see the C Series Module Compatibility Chart.


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3. Complete Data Acquisition

Connectors, Signal Conditioning, and Data Acquisition in a Single Package
Assembling a data acquisition system often involves cabling signal conditioning and connector blocks to a separate device to digitize input signals. These cables and connector blocks add cost and can contribute to noise and error in the system. NI CompactDAQ combines signal connectors, signal conditioning, and ADCs in a single package. This feature eliminates the time and guesswork associated with cabling together multiple components and reduces the number of components that can contribute to noise or failure.

NI CompactDAQ modules include connectors matched to the measurement capability of the module. For example, general-purpose voltage input modules have removable screw terminals, while modules for dynamic and transient signals have BNC connectors. By matching the connectors with the measurement capability of the modules, NI CompactDAQ simplifies sensor and signal installation and further reduces the potential for error by eliminating wire cutting, stripping, and crimping.

For external triggering, or to synchronize multiple chassis, the new 8-slot NI cDAQ-9178 chassis has two BNC connecters built in. These allow the routing of digital timing signals such as sample clocks and triggers to extend or integrate NI CompactDAQ into a larger system.  The cDAQ-9174 and original cDAQ-9172 systems can be synchronized by using a hardware timed digital I/O module for timing and triggering.

Figure 3. C Series modules for NI CompactDAQ include sensor-specific connectors with built-in signal conditioning and A/D converters.

Easy PC Connectivity with Hi-Speed USB
USB has greatly simplified PC-based test and measurement. Because USB is a plug-and-play bus, the NI CompactDAQ chassis and all I/O modules are automatically detected and configured when connected to a USB port. Unlike legacy GPIB and serial devices that require an interface board, NI CompactDAQ connects directly to the USB port through a standard USB cable. This cabling feature eliminates another hidden cost associated with traditional instruments. With simple USB cabling, you can easily move an NI CompactDAQ system from one PC to another. The addition of a thumbscrew locking USB cable to the NI cDAQ-9174/78 chassis protects against accidental disconnects during use, improving ruggedness and usability in industrial settings.

Figure 4. Hi-Speed USB is 40X faster than the preceding USB 1.1, and has 5X the bandwidth of 100 Mb/s Ethernet

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4. Software Options with NI CompactDAQ

Flexible Software – Turnkey Data Logging, LabVIEW, Visual Studio .NET and C/C++
Every NI CompactDAQ chassis is shipped with the free data-logging software package NI LabVIEW SignalExpress LE. With this ready-to-run software, you can quickly acquire, view, and log data to ASCII text files or export to Microsoft Excel for postprocessing. Current NI data acquisition hardware owners can download this free software with the NI-DAQmx  driver and measurement services software. With USB plug-and-play data acquisition and LabVIEW SignalExpress, you can connect NI CompactDAQ to a PC or laptop and start measuring data within three clicks of your mouse.

For more advanced data-logging features, such as alarming, timed logs, analysis, and reporting, LabVIEW SignalExpress – a full-featured nonprogramming development environment seen in figure 5 – works with all devices that run NI-DAQmx, including NI CompactDAQ. See Table 1 for a feature comparison between LabVIEW SignalExpress and LabVIEW SignalExpress LE.

For greater flexibility, NI CompactDAQ also includes the NI-DAQmx driver and measurement services software for LabVIEW, NI LabWindows™/CVI, C/C++, and Visual Studio .NET.  In addition to basic driver functionality, NI-DAQmx includes a configuration management and testing utility, and the DAQ Assistant wizard for the LabVIEW.. LabVIEW is an industry-leading graphical programming and development environment for designing test, measurement, and control systems. It combines the flexibility of a programming language with built-in tools designed specifically for test, measurement, and control to create applications ranging from simple temperature monitoring to sophisticated control systems.

To learn more about data logging software from National Instruments, see the Three Levels of Data-Logging Software from National Instruments tutorial.

Figure 5. This image shows an example of the LabVIEW SignalExpress UI.

You can directly convert both LabVIEW SignalExpress and LabVIEW SignalExpress LE into LabVIEW graphical code for advanced programming and data acquisition capabilities. LabVIEW SignalExpress is included in every LabVIEW development system, or you can purchase it as a stand-alone package.


LabVIEW SignalExpress LE

LabVIEW SignalExpress

Ability to perform simple continuous data logging

Acquisition from more than one device

Multiple UI indicators

Autolaunch for USB devices

NI-DAQmx support

Getting started guide

LabVIEW code generation

Historical data navigation

Exportation to Excel or other spreadsheet

Ability to load saved data

Multiple log files

More than 200 analysis functions


Dynamic report generation

Table 1. This chart shows a comparison of LabVIEW SignalExpress features.

More Channels, Less Space
Instrument space is valuable and large data acquisition systems often take up more than their fair share of it. NI CompactDAQ chassis are available in two sizes, the 4-slot cDAQ-9174 and the 8-slot cDAQ-9178. The 8-slot chassis can measure up to 256 channels of I/O in a 25 by 9 by 9 cm chassis.

NI CompactDAQ is ideal for applications that require portability. It fits easily in a laptop bag, or the available instrumentation case, and can be powered by DC sources for in-vehicle and other applications where AC wall power is not available.

Figure 6. NI CompactDAQ is shown beside a small laptop to demonstrate the portability.

Carrying Case for the Portable NI CompactDAQ USB System
The CASE-0750 (PN 780315-01) is a great way to transport and store a complete NI CompactDAQ instrumentation system as seen in figure 7. The case was specially designed for portable devices from NI, including NI CompactDAQ and USB M Series devices. It has removable foam inserts to further customize the size. With the foam blocks removed as seen in figure 8, there is enough room for two NI CompactDAQ chassis full of modules, associated power supplies, and USB cables. For labs or classrooms with multiple NI CompactDAQ setups and multiple users, the instrumentation case is a good way to store systems with all components in the same place.

The carrying case feature set includes:

  • Shoulder strap with metal clasp (included)
  • Rubber O-ring secured enclosure for a weather tight seal
  • Rubber grip handle for comfortable carrying
  • Lock lug for security (locking mechanism not included)
Figure 7. CASE-0750 is shown next to NI CompactDAQ hardware. Figure 8. This image shows the open case with chassis and modules (not included). The shoulder strap seen on the right is included.

Improved Safety and Accuracy with Digital Isolation
All but three of the NI CompactDAQ modules (NI 9233/34 and NI 9402) are digitally isolated from the chassis and from other modules. Isolation prevents harmful signals from electrostatic discharge (ESD), lightning, and power surges from damaging the carrier, other modules, and the host PC. Most I/O modules feature up to 2,300 Vrms isolation (withstand), and 250 Vrms isolation (continuous). Each component comes with a variety of international safety, electromagnetic compatibility (EMC), and environmental certifications and ratings.

Industrial Features Deliver USB Plug and Play to Rugged Applications
Many modules have features that are advantageous, or even required, in industrial settings. Some of these features include:

  • 4 to 20 mA measurement and control
  • Strain relief available for laptop side of USB cable (part number 777550-01)
  • Multiple modules now available with channel-to-channel isolation
  • Industrial enclosures (see Figure 10)
  • Rugged chassis made of A380 metal
  • 30 g shock rating and -20 to 55 °C temperature rating
  • Up to 2300 Vrms module-to-chassis isolation available on several modules
  • DIN-rail, rack-mount, and panel-mount options (see the Accessories model pages)
  • Strain relief for USB cable on chassis
  • Module backshells available for safe high-voltage connections (see Figure 9)
Figure 9. High-Voltage Backshell

Figure 10. Industrial Enclosure


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5. Frequently Asked Questions

Buy Now
Assemble your system using the NI CompactDAQ Configuration Advisor or learn more about pricing and purchasing information at the NI CompactDAQ chassis model pages.

More Technical Information
NI CompactDAQ under the Hood – Three Technologies That Drive USB Performance

The mark LabWindows is used under a license from Microsoft Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and other countries.

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