The Mitsubishi Electric Q1MEM-128S is a memory card for the Q series programmable logic controller family, used to store the user program and parameter data that define how the PLC controls its I/O and fieldbus network. It slots into the memory card interface on the Q series CPU base unit — the physical fit is consistent across the range, but the CPU firmware version must support the memory capacity.
Compatibility and capacity — what the evidence shows
The memory capacity of the Q1MEM-128S is not explicitly stated in the available specifications — the order code itself suggests 128 kilobytes (128 K), which is the standard sizing convention for Mitsubishi Q series memory cards. Compatibility with all Q series CPUs is not guaranteed: the Q00U CPU, for example, has a specific memory card slot and firmware that may or may not accept the Q1MEM-128S depending on the CPU's firmware revision. Check the CPU hardware manual before specifying.