The extension PLT identifies files that contain data in the page description and plotter control language HP-GL (HPGL) in an ASCII text. Hewlett-Packard developed this language for the control of pen plotters and it was subsequently adopted by other manufacturers. Inkjet (inkjet) and laser printers can also be controlled with HP-GL.
HP-GL files are also used for the exchange of vector data. Many CAD programs support export in HP-GL format. However, they can also be generated by printing in a file and setting a corresponding printer / plotter eg The HP750C. However, this method also carries risks because full compatibility can not be guaranteed.
For these files the extensions hpgl, hgl, hpg and less prn are used. Changing the extension may be useful if the PLT file can not be opened directly.
Most often resolving problems with opening PLT files is very simple. Just install an appropriate program that supports such files. All of the listed programs support PLT files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of PLT files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate PLT files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the AutoCAD applications is not on the list, select "Browse" option in order to manually locate the directory where AutoCAD has been installed.
Sometimes problems with opening PLT files may not lie with the application itself, but can arise due to other causes, such as: