1、LabVIEW 1 overview LabVIEW is a program development environment, by the national instruments (NI) research and development company, similar to the C and BASIC development environment, but with other computer language LabVIEW significant difference is: other computer language is based on the text, an
2、d the language code of graphical LabVIEW use scripting language G program, application is in the form of block diagram. A complete, LabVIEW virtual instrument system of open application software development, and use it to form instrument testing system and data collecting system can simplify the des
3、ign procedure. With Visual C+ LabVIEW, Visual Basic,LabWindows/CVI, etc, which adopts different programming language is based on the text language program Code (Code), and abVIEW L is using graphical programming language), Graphic (G instead of the traditional diagram of the Code. The Lab VIEW of eq
4、uipment with the scientists and engineers icon in the habit of basic agreement, this makes the icon programming process and thinking process is very similar. LabVIEW convenient calls Windows DLL and user-defined function in the DLL, LabVIEW also provides CIN (C) Node with any users can use by C + +
5、language or, if the ANSI C, compiled program modules, makes a open LabVIEW development platform. LabVIEW also directly support dynamic data exchange (DDE), structured query language (SQL), TCP and UDP network protocol. In addition, the LabVIEW also provides special used for program development kit,
6、users can easily set breakpoints, dynamic program execution to very intuitive image observation data transmission process, and convenient debug. The operation mechanism is LabVIEW macroeconomic sense is no longer the von neumann traditionally computer system structure of the method. The traditional
7、computer language (such as C) to the order of execution by parallel structure in LabVIEW mechanism； Essentially, it is a kind of control Flow structure with graphical Data Flow pattern (Data Flow Mode), this kind of means to ensure the process of any Node Function in hire those knowledgeable program
8、mers only after all it can only be executed Data. That is to say, in the data flow in the concept of program execution, and it is the data driven by operating system, calculate machine and so on. 1 Since LabVIEW program is data flow driven, data flow design program, a goal only when its all input ca
9、n only be effective, And the goal of output only when it is complete. So, in VIEW of the Lab is connected the data flow between nodes function control program execution sequence, and dont like text program execution sequence by rows of constraint. Thus, we can be connected through the rapid developm
10、ent of concise function node applications, even can have multiple data synchronization operation channel, the so-called Multithreading (Multithreading). 2 Data Storage and Reporting with NI LabVIEW The continued increase in processing and storage capacity and the decrease of hardware and software co
11、sts has resulted in an explosion of collected data being acquired. But while technology is enabling faster and richer data retention, storing, managing, and sharing data remains the real challenge. Traditional software packages tend to take one of two limiting approaches: 1) they force you into a pa
12、rticular format that is not exchangeable with other applications or users or 2) saving data is left so open ended you waste time trying to determine the best way to organize and save your data to disk so you can share it. NI LabVIEW, designed for the entire engineering process, includes built-in fun
13、ctionality to help you easily save data to disk and create professional reports. By providing easy yet robust interfaces for file I/O and reporting, you can make the most of your acquired data to make decisions faster. (1)File I/O Designed Specifically for Engineering Data Despite the fact that LabV
14、IEW offers a wide variety of file I/O options, these traditional file types rarely meet all the criteria you need in a file format. For example, ASCII files are exchangeable, but are very large and slow to read and write. On the other hand, binary file read and write speeds can keep up with high-spe
15、ed hardware, but are difficult to share with others. Because 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. TDMS files are based on the TDM da
16、ta model for saving well-organized and documented test and measurement data. The TDM data model offers three levels of hierarchy, as shown in Figure 2 file, group, and channel. The file level can contain an unlimited number of groups, and each group can contain and unlimited number of channels. Beca
17、use of this channel grouping, you can organize your data to make it easier to understand. For example, 2 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. Figure 1. The TDM
18、data model meets the specific requirements of measurement data. Also, you can insert your own custom properties at each of the three levels. Each level accepts an unlimited number of custom-defined attributes to achieve well-documented and search-ready data files. The descriptive information located
19、 in the TDMS file, a key benefit of this model, provides an easy way to document the data much like you would document code. As your documentation requirements increase, you do not have to redesign your application, you simply extend the data model to meet your needs. (2)Multiple Easy-to-Use Program
20、ming Interfaces Because it was developed to meet the needs of all engineers, TDMS offers ease of use, high-speed streaming, and exchangeability. Like many operations in LabVIEW, you can use multiple interfaces to write TDMS files. You can quickly read and write TDMS files using a virtual instrument
21、(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. 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 (3)F
22、iles Exchangeable with Other Programs such as Microsoft Excel Because you may be required to work in additional applications, TDMS is easily exchangeable across other programs. You can open TDMS files in Microsoft Excel using the TDM Excel Add-In, which installs with NI software and is available free at Description Title Author etc UUT Procedure Name Comment Unit Max&Min
