What it is and what it does
The Mitsubishi FX3G-EEPROM-32L is an EEPROM memory cassette designed for the FX3G and FX3S series PLCs. It provides a loader function that allows program writes without requiring battery backup, and includes a protect switch to prevent accidental overwrites — a practical safeguard during commissioning or field updates. Memory capacity is 32000 steps when used with an FX3G base unit; on the FX3S series it is limited to 16000 steps, with a program capacity ceiling of 4000 steps. This means the cassette offers headroom for larger programs on the FX3G, while on the FX3S the effective usable space is constrained by the base unit's architecture.
Where it fits
The cassette plugs directly into the memory slot on FX3G or FX3S PLC base units. No battery backup is needed for retention — EEPROM holds the program without power, which simplifies long-term storage and reduces maintenance on panels where battery changes are inconvenient.