How to Choose Between NI Data Acquisition Devices or Systems

A data acquisition device turns a PC into a measurement system, extending it with analog and/or digital I/O channels that let you read in voltage and pulse trains, control digital lines, and more. Data acquisition devices can be either single-function (for example, only measuring voltage) or multifunction, combining various types of I/O, such as analog and digital I/O and counter/timer functionality. Data acquisition devices offer fixed functionality and are ideal for projects in which requirements do not change and scalability is not a concern. Because measurement applications differ, you can use the USB form factor for ease and convenience, or you can use a PCI or PCI Express form factor when you need bandwidth and low latency.

Most NI data acquisition devices ship with our measurement-ready interactive software, DAQExpress, that seamlessly connects to your hardware for quick measurements, data recording, and analysis. Also, NI data acquisition devices fully integrate with LabVIEW and directly into MathWorks MATLAB^® software using the MathWorks Data Acquisition Toolbox for MATLAB® and Simulink®. Additionally, with our NI-DAQmx driver that supports all NI data acquisition devices, you can take measurements using Python, C#.NET, and ANSI C, and use the examples provided in your application.

Data acquisition systems (DAS), also called DAQ systems, help validate designs and identify product defects early in the development process. With thousands, if not millions, of products in development every day, you can imagine how many different measurement systems there are.

NI data acquisition systems are built on modular hardware that gives you the freedom to build mixed-measurement systems to meet your specific requirements. While there are two main hardware approaches to consider, options on the software side span from FlexLogger^TM, no programming required, configurable data acquisition application software to a variety of programming languages such as Python, C#.NET, and ANSI C, in addition to full integration with LabVIEW, and MATLAB using the MathWorks Data Acquisition Toolbox.

FlexLogger™ Data Acquisition Software

FlexLogger  data acquisition software minimizes the time you would spend on setup and lets you focus on getting the measurements you need. It provides sensor-focused, menu-based workflows for a flexible measurement system that can mix analog sensors, digital I/O, automotive networks, and more. You can extend FlexLogger software’s functionality by integrating third-party hardware or custom analysis with plug-ins.

FlexLogger^TM software supports calibration, alarming, and customizing visual interfaces based on dragging and dropping visual components onto your screen. You have full control over how your data is logged, with options to save data in one or multiple files, start logging based on a key input or alarm triggers, and import metadata from the test to simplify data management. You can view data that has been logged in the FlexLogger data viewer, which visualizes data from multiple sensors and calculated channels, yielding faster insights into your data.

CompactDAQ Hardware

CompactDAQ is a portable, flexible data acquisition approach consisting of a CompactDAQ chassis and C Series I/O modules. It has a capacity of up to 14 I/O modules per chassis and is ideal for applications with a wide mix of measurement types, where scalability and flexibility are important. An Ethernet CompactDAQ chassis can be synchronized over a network, providing tight synchronization across multiple chassis. The ruggedness of the hardware makes CompactDAQ a great fit for high-channel-count distributed DAQ applications in the field.

The C Series I/O modules cover a wide range of input and output functionality. Some modules are sensor-specific, with modules designed to condition sound and vibration measurements, strain gages, temperature sensors, and more. Other modules are specialized for voltage, current, digital I/O, and automotive buses such as CAN and LIN. The modules connect to the chassis backplane, which communicates with a host PC over a USB or Ethernet protocol.

NI also offers preconfigured bundles of NI's popular CompactDAQ hardware for common sensor test measurements such as temperature, voltage, strain, or sound and vibration. These bundles include a CompactDAQ chassis, C Series module(s), and any relevant accessories for an easy way to get started with your test system.

PXI Data Acquisition Hardware

PXI hardware provides a modular approach to high-channel-count data acquisition and sensor measurement applications. It offers chassis with up to 18 slots, tight synchronization on the backplane, and the ability to use an in-chassis controller or a connection to an external PC through a remote-control module, all in a self-contained system for high-channel-count data acquisition systems, that is built with the newest chip technology and running a Windows OS.

The PXI modular hardware approach offers multiple signal-conditioning modules that cover a wide range of applications. From a linear variable differential transformer (LVDT) to analog input, with a range from ± 1 V to ± 600 V, and analog output to RTD and thermocouple, sound and vibration (DSA), and strain/bridge modules, you can design systems ranging from tens to hundreds of channels, mixing and matching measurement functionality and output capabilities. If you need more channels, you can expand your system into multiple chassis.

PXIe Controller, Signal Conditioning Modules, and Chassis

NI also offers preconfigured bundles of NI PXI instruments, including oscilloscopes, digital multimeters, SMUs, LCR Meters, and more. These bundles include a chassis, module(s), and any relevant accessories for an easy way to get started with your test system.

Now that we have looked at different approaches to data acquistion, we still need to determine which approach works best for you by taking into consideration additional factors. Because you can use NI data acquisition products for everything from plug-and-play data acquisition, to synchronized, distributed measurements, to high-channel-count systems, consider more than just your current task’s requirements—you may want to reuse the device or system for future projects. Data acquisition devices are well-suited for tasks that remain the same and never need to be expanded. The CompactDAQ modular approach provides the flexibility and scalability you need to add channels or measurement types to the system in the future. Additionally, it’s best for mixed measurements or distributed applications. Finally, in large-channel-count applications or for measuring higher-voltage inputs, the PXIe modular approach lets you design the system to your requirements while being open for future expansion.

While most data acquisition projects are unique, they deliver the data that you use to make business decisions. Choosing an approach that not only fits your current project but can be reused and scaled for multiple projects provides more value for your organization. Requirements should be driving your system configuration, and requirements change between projects—so get the most for your money by considering your long-term measurement needs to help decide which approach is best.