What the 2 MB SRAM card does in a Q-series rack
The Q2MEM-2MBS is an SRAM memory card for Mitsubishi MELSEC System Q PLCs. SRAM is volatile — it requires the PLC's battery backup to retain the program and data when the main power is off. If the backup battery is low or missing, a power cycle wipes the card. Rated capacity is 2 MB; after formatting the usable space is 2034 Kbytes. That gap is the file-system overhead the Q series controller writes during initialisation. Budget for the formatted number when sizing a project. The card stores up to 287 files. This matters when you separate the main sequence, subroutines, parameter blocks, and data-logging recipes into individual files rather than one monolithic project.
Mechanical endurance for field swaps
Rated for 5000 insertion and removal cycles. That is the connector endurance — the card edge and the PLC slot contacts are designed for frequent field swaps during commissioning, firmware updates, or program transfers between machines. After 5000 cycles the contact resistance may drift outside spec. External dimensions are 4.5 cm x 4.28 cm x 0.33 cm. The card sits flush in the Q series CPU or memory slot; no protruding handle or latch extends beyond the module face.
No official successor order code is published for this card. The Q series memory portfolio includes higher-capacity SRAM and flash options, but Mitsubishi has not designated a direct drop-in replacement for the 2 MB SRAM variant. Sourced to order against the BOM quantity through independent distribution.