What it is and what it does
Mitsubishi FX2NC-EEPROM-16C is a memory cassette that plugs into an FX2NC-series PLC to store the user program. Out here in the grease, if you've got an old FX2NC rack still running a line, this is the part that holds the logic. No battery needed—it's EEPROM, so the program stays put through power cycles.