In DOSBox, type:

C:
CD DISK1
INSTALL

Follow the prompts to install to C:\LM90.

If you cannot locate a legitimate Logic Master LM90 software download zip 2021, consider these modern alternatives (most support direct LM90 project imports).

Logic Master LM90 is a DOS-based (later Windows 3.1/95 compatible) programming and documentation software used to configure, program, and troubleshoot GE Fanuc Series 90 PLCs. It supports three primary programming languages as defined by IEC 61131-3:

Some vintage industrial control forums (like PLCtalk.net or MrPLC.com) have archived legal copies under “abandonware” discussion – but proceed with caution and only for educational/preservation purposes.
Neither I nor any responsible platform encourages piracy.

For better compatibility with LM90’s GUI (which supported Windows 3.1), use:

| Problem | Solution | |---------|----------| | “Cannot find LM90.OVL” | Ensure the LM90 folder is in the PATH or you are in the correct directory. | | Serial communication fails | Use serport utility inside DOSBox to map USB COM ports. Or try virtual serial port emulator (VSPE). | | Keyboard not responding | Set usescancodes=false in DOSBox config. | | Mouse does not work in ladder editor | LM90 is keyboard-driven (F1-F10 keys, arrow keys, Enter, Esc). No mouse support. | | Installation asks for disk 2 | Use IMGMOUNT for floppy images, or copy all DISK folders to a single directory and run INSTALL from there (some versions support it). |