How to Choose Between NI Data Acquisition Devices or Systems

概览

If you’re looking for the best fit for your next data acquisition (DAQ) application, NI offers multiple options: From plug-and-play USB or PCI Express DAQ devices that offer fixed functionality, to configurable data acquisition systems that let you mix and match analog, digital, and sensor-specific inputs and outputs, meeting all of your needs. And no matter which option you choose, software is crucial to connect real-world inputs to on-screen visuals so that you can make data-driven and informed business decisions. Let’s take a closer look at these components, compare different data acquisition approaches, and discuss why you would choose one over another. If you are looking for an application-specific solution, NI offers a variety of solutions for applications such as hardware-in-the-loop (HIL) test for automotive, data logging for industrial machinery, or  electromechanical systems test for aerospace and defense.

Contents

When to Use a Data Acquisition Device

数据采集设备能将PC变成测量系统,并通过模拟和/或数字I/O通道对其进行扩展,使您可以读取电压和脉冲序列、控制数字线路等。数据采集设备既可以是单一功能设备(如仅测量电压),也可以是结合了各种类型I/O的多功能设备,如模拟和数字I/O以及计数器/定时器等功能。数据采集设备通常提供固定的功能,非常适合有固定要求且无需考虑扩展性的项目。其中USB组成结构方便易用,而PCI或PCI Express组成结构则可满足带宽和低延迟需求,从而适用于不同的应用。

大多数NI数据采集设备均随附即测即用的交互式软件DAQExpress,该软件可与您的硬件无缝结合,实现快速测量、数据记录和分析。此外,NI数据采集设备与LabVIEW完全集成,并且可直接连接采用了MATLAB® and Simulink®数据采集工具箱的MathWorks MATLAB®软件。此外,借助支持所有NI数据采集设备的NI-DAQmx驱动程序,您可以使用Python、C#.NET和ANSI C进行测量,同时也可使用应用随附的范例。

DAQExpress和DAQ设备

How to Build a Data Acquisition System with NI Hardware and Software

数据采集系统(DAS)也称为DAQ系统,有助于在开发过程的早期验证设计并识别出产品缺陷。每天都有成千上万甚至数百万种产品处于开发过程中,因此可以想象,测量系统的种类数量将会有多么庞大。

NI数据采集系统基于模块化硬件而构建,让您可以自由搭建混合测量系统来满足特定要求。尽管硬件方面只有两种主要方案可供选择,但软件方面的选择却十分广泛,其中包括无需编程且可配置的数据采集应用软件FlexLoggerTM,以及Python、C#.NET和ANSI C等多种编程语言,除了可与LabVIEW完全集成,还可使用MathWorks数据采集工具箱与MATLAB集成。

数据采集系统

FlexLogger™数据采集软件

FlexLogger 数据采集软件最大程度地减少了设置和配置时间,让您可以专注于获取所需的测量数据。它为灵活的测量系统提供了以传感器为中心、基于菜单的工作流程,可混合使用模拟传感器、数字I/O、汽车网络。您可以集成第三方硬件或使用插件来定制分析,从而扩展FlexLogger软件的功能。

FlexLoggerTM软件允许将可视组件拖放到屏幕上,进而支持校准、报警和自定义可视界面。您可以完全控制数据的记录方式,比如选择将数据保存在一个或多个文件中、根据按键输入或警报触发器开始记录,或者从测试中导入元数据来简化数据管理。还可以在FlexLogger数据查看器中浏览已记录的数据,该查看器能够对来自多个传感器和计算通道的数据进行可视化处理,从而让您更快速了解数据包含的信息。

FlexLogger数据采集应用软件

CompactDAQ硬件

CompactDAQ是一种便携灵活的数据采集方案,由CompactDAQ机箱C系列I/O模块组成。每个机箱最多可容纳14个I/O模块,非常适合需要混合进行多种测量且需要可扩展性和灵活性的应用。以太网CompactDAQ机箱可以通过网络进行同步,从而实现多个机箱的紧密同步。CompactDAQ的硬件坚固耐用,因此非常适合现场的高通道数分布式DAQ应用。

C系列I/O模块涵盖了多种输入和输出功能。部分模块专为特定传感器而设计,旨在调理声音和振动测量、应变计、温度传感器等。其他模块则专门针对电压、电流、数字I/O和汽车总线(如CAN和LIN)等进行设计。这些模块与机箱背板相连,该背板又通过USB或以太网协议与主机PC进行通信。

CompactDAQ和C系列I/O模块

PXI数据采集硬件

PXI硬件为高通道数的数据采集和传感器测量应用提供了模块化方案。它具有多达18个插槽的机箱,提供紧密同步的背板,还能使用机箱内控制器或通过远程控制模块连接到外部PC,所有这些都融入自成一体的系统,适用于高通道数数据采集系统,该系统采用当下最新的芯片技术构建并运行Windows操作系统。

PXI模块化硬件方案提供了多个信号调理模块,涵盖了多种应用。从线性可变差分变压器(LVDT)到模拟输入(范围为±1 V到±600 V),从模拟输出RTD和热电偶声音和振动(DSA)以及应变/桥模块,您可以设计从数十个通道到数百个通道不等的系统,混合并匹配测量功能以及输出功能。如果需要更多通道,可以将系统扩展为多机箱系统。

PXIe控制器、信号调理模块和机箱

How to Choose a Data Acquisition Approach

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.