A direct memory dump of the 8-bit or 16-bit EPROM. The PMC program starts at a known offset (e.g., 0x8000 for many Series 0 models). The structure is:
The tool performed two primary conversions:
A critical feature of the tool was its handling of PMC types. Fanuc used different PMC architectures (PMC-L, PMC-M, PMC-C) each with unique memory maps. Choosing the wrong conversion would result in a "Format Error" on the CNC. The Convert Tool provided dropdown menus for selecting the exact PMC model and EPROM device. Fanuc Pmc Eprom Convert Tool
While specific steps vary by Fanuc software version, the typical workflow is:
Step 1: Read the EPROM
Use a hardware EPROM programmer (e.g., Data I/O, Needham’s, or a TL866) to read the physical 27C256, 27C512, or similar chip. Save the file as machine.BIN. A direct memory dump of the 8-bit or 16-bit EPROM
Step 2: Convert Binary to Mnemonic Open the Fanuc PMC EPROM Convert Tool. Select File → Convert → Binary to Mnemonic.
Step 3: Edit the Logic
Open the .MNQ file in any text editor (Notepad++ works well) or import it into Fanuc FAPT Ladder. Add your desired changes. Warning: A single misplaced contact can crash the machine. Validate carefully. A critical feature of the tool was its
Step 4: Convert Back to Binary Run the tool again: Mnemonic to Binary.
Step 5: Program & Test
Use your EPROM programmer to burn new_machine.BIN onto a new EPROM (never overwrite the original without keeping a backup). Install the new EPROM and test the machine in a controlled environment.