新旧版本VI之间的转换

工作中经常需要对老旧系统进行升级，此时就需要打开旧版本LabVIEW创建的VI或者在新旧VI之间进行转化。这种情况下，可参阅下表选择合适的版本或转换工具来完成。

其中LabVIEW 3.x以及之前版本创建的VI，需要借助LabVIEW VI Conversion Kit免费工具才能转换为较高版本支持的VI（表中注解C）。LabVIEW8.5以及后续版本要打开LabVIEW6.0之前版本创建的VI，需要先将其转换为LabVIEW6~8.2.x，然后再由LabVIEW8.5.x或者后续版打开（表中注解I）。这意味着若要在LabVIEW8.5以及后续版本要打开LabVIEW3.x之前版本的VI，就需要先借助LabVIEW VI Conversion Kit将其转换为LabVIEW6~8.2.x版本，再由LabVIEW8.5.x或者后续版打开（表中注解C+I）。

反过来看，LabVIEW8.0及以上版本可以将VI直接另存为LabVIEW8.0或高于8.0但低于其的版本。但是若要将VI从高版本转换为对于低于7.1.x的版本，则需要借助中间版本的LabVIEW来实现转化过程。例如，若要将LabVIEW8.2.x版本的VI另存为LabVIEW7.1.x版本，则需要先将VI另存为LabVIEW8.0.x版本，再由LabVIEW8.0.x另存为7.1.x版本（表中注解M）。

在进行VI版本转换前，需考虑以下几点

• New VI Functionality: VIs that have functionality introduced in a later version of LabVIEW cannot fully function in a previous version of LabVIEW where the new functionality does not exist. In this case, when you save the new VI for a previous version, the new functionality will be missing in the older version of the VI. The VIs that do not work will be replaced with VIs containing question marks on the block diagram.

• VIs from Toolkits: You cannot save VIs in toolkits for previous versions. This is because toolkits have their own versions, and you can only have a toolkit installed for one version of LabVIEW at a time on a machine.

• Functions from vi.lib: VIs in vi.lib are also not saved for previous versions. There is no need to save a VI to a previous version when that VI already exists in that version. When you save a VI for a previous version of LabVIEW, the vi.lib VIs are not converted, but the reference to that VI will remain. When the VI is then opened up in the previous version of LabVIEW, the newly converted VI links to the vi.lib VI of that version of LabVIEW. This process saves time and disk space. The newly converted VI will function the same using the previous version of the vi.lib VI.

最后，如果实在有困难，可以戳在https://forums.ni.com/t5/Version-Conversion/bd-p/VersionConversion?profile.language=en寻求帮助。