![]() With under-the-hood optimizations for bypassing buffering, TDMS is the fastest way to write data on the NI platform. With multiple interfaces for writing TDMS files, you can choose the one that best fits your needs.Īlthough TDMS is designed to be easy to use, with the major speed improvements in hardware over the last several years, it is also important for TDMS to be optimized for high-speed streaming so that file I/O is not the bottleneck when determining your acquisition speeds. Also, when using LabVIEW with NI-DAQmx, you can use the Configure Logging VI from the DAQ palette or log directly from the NI DAQ Assistant, as seen in Figure 3.įigure 3. You can quickly read and write TDMS files using a virtual instrument (VI) such as the Write To Measurement File Express VI or, for the best performance and customization, use the primitive TDMS VIs from the File I/O palette. Like many operations in LabVIEW, you can use multiple interfaces to write TDMS files. ![]() Multiple Easy-to-Use Programming Interfacesīecause it was developed to meet the needs of all engineers, TDMS offers ease of use, high-speed streaming, and exchangeability. As your documentation requirements increase, you do not have to redesign your application, you simply extend the data model to meet your needs. The descriptive information located in the TDMS file, a key benefit of this model, provides an easy way to document the data much like you would document code. Each level accepts an unlimited number of custom-defined attributes to achieve well-documented and search-ready data files. The TDM data model meets the specific requirements of measurement data.Īlso, you can insert your own custom properties at each of the three levels. For example, you may have one group for your raw data and another group for your analyzed data within one file, or you may have multiple groups that correspond to sensor types or locations.įigure 2. Because of this channel grouping, you can organize your data to make it easier to understand. The file level can contain an unlimited number of groups, and each group can contain and unlimited number of channels. The TDM data model offers three levels of hierarchy, as shown in Figure 2 – file, group, and channel. TDMS files are based on the TDM data model for saving well-organized and documented test and measurement data. On the other hand, binary file read and write speeds can keep up with high-speed hardware, but are difficult to share with others.īecause of the drawbacks of traditional file I/O, National Instruments developed the Technical Data Management Streaming (TDMS) file format to meet the specific needs and high demands of engineers and scientists. For example, ASCII files are exchangeable, but are very large and slow to read and write. Because good file I/O practices can be one of the trickier parts of building any test or measurement system, NI LabVIEW ships with dozens of examples that you can use to get started with each of the file types.įile I/O Designed Specifically for Engineering Dataĭespite the fact that LabVIEW offers a wide variety of file I/O options, these traditional file types rarely meet all the criteria you need in a file format. With LabVIEW, choose from many interfaces for reading and writing files, depending on your needs.Īs seen in Figure 1, LabVIEW includes basic functions you can use to build files from scratch as well as Express VIs for configuring file I/O parameters from a dialog so you don’t have to worry about details such as opening file references, string formatting, and endianness. Simple inclusion of meta information and propertiesĪs each application is different, LabVIEW contains a wide array of file I/O options for you to choose from, including ASCII, binary, datalog, ZIP, and XML.įigure 1.You have many characteristics to consider when evaluating storage formats: You need to pick a format that meets your requirements in your current system, but that can also scale as your test needs change. Choosing the right file format for saving data in your test system can be a big decision.
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