Siemens SIMATIC S7-300 / S7-400 / S7-1200 MC Memory Card

Description

• S7-300 CPUs (MLFB with ‘-2’ or ‘-3’ suffix CPUs: CPU 312C-2 DP, CPU 313C, CPU 314C-2 PN/DP, CPU 315-2 DP/P, CPU 317-2 PN/DP, etc. — all S7-300 CPUs exceptvery old CPU 312/313/314 with MC (Memory Card PCMCIA-like — obsolete)
• S7-1200 CPUs (all S7-1200 CPUs — 1211C/1212C/1214C/1215C/1217C — S7-1200 requiresMMC to run; 4 MB is minimum practical for small programs, also usable as program card / data log card)
• S7-400 CPUs (as load memory / program backup card— S7-400 work memory is on CPU; MMC stores user program, comments, data blocks for reload. S7-400 also supports larger MMCs: 8LT03=8MB, 8LT04=16MB, 8LT06=64MB etc.)

1. Program Storage (Load Memory)​ — holds compiled user program, symbol table, comments, data blocks downloaded from PG/PC.
2. Startup / Mode Switch​ — S7-300/1200 will NOT run without MMC inserted(unlike S7-400 which has onboard work mem — but still needs MMC for program load & retention).
3. Data Logging / Recipe Storage​ (on S7-1200 / S7-300 with appropriate firmware — write data to MMC via WRITE_DBLetc.)

Key Features

• Capacity: 4 MB (usable ~ 3.7 MB after file system overhead — sufficient for small-to-medium S7-300 / S7-1200 projects; S7-400 usually wants ≥8 MB unless just for backup)
• Type: Siemens SIMATIC MMC (based on MMC standard but with Siemens-specific ID — NOT interchangeable with generic camera MMCs!​ Use only Siemens 6ES7954-8L□ cards)
• Compatibility: S7-300 (MMC-based CPUs only — CPU 31xC, 315-2 DP/PN, 317-2 PN/DP etc.), S7-1200 (all), S7-400 (as load memory / backup)
• Write Cycles: ≥ 100,000 erase/write cycles (Flash — suitable for infrequent program download; for heavy data logging consider wear — S7-1200 data log functions manage wear leveling)
• Country of Origin: Germany / Taiwan / China (Siemens A&D)

Model & Variant Reference (Siemens S7 MMC Family — 6ES7954-8Lxx Series)

⚠️ Critical Notes:

1. S7-300 MMC-based CPUs ONLY: CPUs 312 IFM, 313, 314 (old 6ES7312-1AE0x)​ use MC (Memory Card — PCMCIA-format FEPROM/Flash — 6ES7951-… / 6ES7952-…)​ — they cannot use this MMC (6ES7954-…). MMC-based S7-300 CPUs are those introduced ~1999+: CPU 312C, 313C, 314C, 315-2 DP/PN, 317-2 PN/DP, 319-3 PN/DP etc. Check your CPU MLFB!
2. S7-1200 Requires MMC: S7-1200 will notgo to RUN without MMC inserted. 4 MB is minimum viable; if your project + data log exceeds ~2–3 MB usable, step up to 8 MB (8LT03).
3. Do NOT Use Generic MMC/SD: Siemens MMCs have proprietary ID bytes — generic camera MMCs will be rejected by S7-300/1200/400 (“Insert/Remove MMC” diagnostic — card not recognized). Only use 6ES7954-8L□ cards.
4. Format / Erase: In STOP mode — remove & re-insert MMC → CPU may offer “Delete User Program” (depending on CPU FW) OR use PG/PC → Online → “PLC → Memory Reset (Clear/Reset)” which erases MMC content (CPU must be in STOP). Never pull MMC out while CPU in RUN — can corrupt card!​
5. S7-400 Usage: S7-400 CPU has work memory onboard — MMC stores load memory (user program copy, symbols, comments, archived data). On power-up S7-400 copies from MMC → work mem. MMC also used for firmware update & as data log medium on some 400H/F systems.

Technical Specifications (6ES7954-8LT02-0AA0 — 4 MB SIMATIC MMC)

Warranty & After-Sales

• Factory new units: 12 months warranty
• Refurbished units: 3-6 months warranty (format test & program download/read-back in S7-300/1200 test rig)
• Technical support for:
  • CPU compatibility check (confirm your S7-300 is MMC-based — e.g., CPU 315-2 EH13/14 → yes; old CPU 313-1AD01 → NO (needs MC card 6ES7951-…))
  • S7-1200 MMC sizing (4 MB OK for small prog; if using data logging or large retained DB → recommend 8 MB 8LT03)
  • MMC handling procedure (insert/remove ONLY in STOP or POWER OFF — never in RUN; how to clear: PG/PC → Online → PLC → Reset / “Delete User Program” via mode switch prompt)
  • S7-400 load memory usage explanation (MMC vs work mem)
  • Cross-ref to larger MMCs (8LT03=8MB, 8LT04=16MB, 8LT06=64MB) if project outgrows 4 MB
• Optional: S7-300 starter kits, PG/PC MPI USB adapter (6ES7972-0CB20-0XA0 PC Adapter USB A2)

Delivery Time

• Standard delivery: 3-5 working days (stock items)
• Express shipping available upon request

Why Choose Our Store

• Genuine Siemens SIMATIC MMC — not generic MMC (will NOT be rejected by CPU)
• Global supply network with competitive pricing
• Expertise in S7-300/1200/400 memory card selection (capacity, CPU compatibility, handling precautions)
• Comprehensive technical documentation (MMC insert/remove procedure, clear memory steps, compatibility table)
• Responsive customer service and support

Applications

• S7-1200 Program & Retain: Mandatory for S7-1200 — holds user program, retentive DBs, optional data logs/recipes.
• S7-300 MMC-based CPU: Stores user program, symbols, comments — CPU cannot RUN without it (MMC-based CPUs).
• S7-400 Load Memory / Backup: Holds downloaded project for reload after power loss; archive copy of program + symbols.
• Data Logging (S7-1200 / S7-300 FW ≥ V2.5+): Write CSV-style data logs to MMC for quality / batch records (4 MB limits total log size — for larger logs use 64 MB 8LT06).
• Retrofit / Spare: Exact 6ES7954-8LT02-0AA0 — plug into CPU, download project → RUN.