Mitsubishi MELSEC-Q Series Memory Modules: Q2MEM-32MBA

Technical Dossier

Product Details And Specifications

Mitsubishi Electric MELSEC-Q Series Technical Notes

The Mitsubishi Electric MELSEC-Q Series is a modular programmable logic controller (PLC) platform deployed across global heavy industry sectors including petrochemical refining, nuclear power generation, steel manufacturing, and large-scale water treatment infrastructure. Introduced in the late 1990s as the successor to the MELSEC-A and MELSEC-QnA platforms, the Q Series established itself as the dominant DCS/PLC hybrid architecture in Asia-Pacific industrial installations and maintains a substantial installed base in European and North American process plants. Its multi-CPU configuration capability — supporting up to four independent CPUs on a single base unit — made it the reference architecture for redundant safety-critical control loops. The Q2MEM-32MBA is a 32 MB flash memory card used for program storage, parameter backup, and file register extension within this ecosystem.

The Evolution of MELSEC-Q Series Architecture

The MELSEC-Q platform launched commercially circa 1999 with the Q02 and Q06H CPU modules, establishing a backplane bus architecture (Q bus) that remained backward-compatible across three major hardware generations. Generation 1 (Q00/Q01/Q02/Q06H) introduced the standardized base unit format with 3-, 5-, 8-, and 12-slot configurations. Generation 2 introduced the Universal Model CPUs (Q03UD, Q04UD, Q06UD, Q13UD, Q26UD) with expanded program capacity, built-in Ethernet, and SD card interfaces — partially displacing the Q2MEM SRAM/flash card format for new installations. Generation 3 saw the introduction of the iQ-R Series (R04CPU, R08CPU, R16CPU, R32CPU, R120CPU) as the designated long-term successor platform, with Mitsubishi Electric formally announcing the MELSEC-Q Series transition to the mature/maintenance phase. For installations still operating on Q Series hardware — particularly those using Basic Model CPUs (Q00, Q01, Q02) and High Performance Model CPUs (Q02H, Q06H, Q12H, Q25H) — the Q2MEM memory card family remains the only compatible program storage medium. Migration to iQ-R requires full hardware replacement and program re-engineering, making long-term spare parts availability for Q2MEM modules a critical operational concern for plant maintenance teams.

MELSEC-Q Series Full Catalog & Functionalities (SKU List)

Memory Cards (Q2MEM Family)

• Q2MEM-32MBA: 32 MB flash memory card for program and parameter file storage on Q Series Basic/High Performance CPUs.
• Q2MEM-8MBA: 8 MB flash memory card; entry-level capacity for smaller Q Series program configurations.
• Q2MEM-16MBA: 16 MB flash memory card; mid-range capacity for standard Q Series deployments.
• Q2MEM-64MBA: 64 MB flash memory card; maximum capacity variant for large-scale program and file register storage.
• Q2MEM-8MBS: 8 MB SRAM memory card; supports battery-backed file register data retention.
• Q2MEM-16MBS: 16 MB SRAM memory card; battery-backed data storage for process variable logging.

CPU Modules

• Q02CPU: Basic Model CPU; 20K step program capacity; compatible with Q2MEM flash cards.
• Q06HCPU: High Performance CPU; 60K step capacity; standard workhorse for mid-scale process control.
• Q12HCPU: High Performance CPU; 124K step capacity; suited for complex multi-axis and process applications.
• Q25HCPU: High Performance CPU; 252K step capacity; top-tier Q Series program memory.
• Q03UDCPU: Universal Model CPU; 30K step; built-in Ethernet port; SD card interface replaces Q2MEM in new designs.
• Q13UDEHCPU: Universal Model Enhanced CPU; 130K step; dual built-in Ethernet; high-speed bus.

I/O and Signal Modules

• QX40: 16-point DC input module; 24 VDC sink/source; standard digital input for field devices.
• QY10: 16-point transistor output module; 12–24 VDC; open-collector sink type.
• QX80: 32-point DC input module; high-density digital input for compact panel designs.
• QY80: 32-point transistor output module; sink type; high-density digital output.
• Q64AD: 4-channel analog input module; 16-bit resolution; 4–20 mA / 0–10 V selectable.
• Q62DA: 2-channel analog output module; 16-bit resolution; voltage and current output.
• Q68ADV: 8-channel voltage analog input; high-speed sampling for process monitoring.

Communication and Network Modules

• QJ71E71-100: Ethernet interface module; 100BASE-TX; MELSOFT/SLMP protocol support.
• QJ71BR11: CC-Link master/local module; up to 64 stations; 10 Mbps fieldbus.
• QJ71LP21-25: MELSECNET/H optical loop module; high-speed inter-PLC network.