S7-300 PLC Program Storage Solution – SIEMENS 6ES7953-8LJ30-0AA0 | Micro Memory Card Series
Where This Product Is Used
The SIEMENS 6ES7953-8LJ30-0AA0 Micro Memory Card (512 KB) is deployed across a wide range of industrial automation environments where reliable, non-volatile program storage is essential for SIMATIC S7-300 PLCs. Typical application scenarios include:
- Automotive Assembly Lines — Stores PLC logic for robotic welding, body-in-white transfer lines, and paint shop conveyors where program integrity must survive power cycles and emergency stops.
- Food & Beverage Processing — Used in filling, capping, and packaging machines requiring hygienic-area PLCs with compact, sealed memory modules.
- Water & Wastewater Treatment Plants — Retains SCADA-linked PLC programs in remote pump stations and filtration control panels operating in harsh, humid environments.
- Chemical & Petrochemical Plants — Supports S7-300 CPUs in explosion-proof enclosures where field-replaceable memory cards enable rapid CPU swap-out without re-programming.
- Machine Tool & CNC Integration — Stores motion-control sequences and safety interlocks for milling, turning, and grinding machine PLCs.
- Building Automation & HVAC — Deployed in BMS controllers managing air handling units, chillers, and energy metering systems.
- Power Generation & Utilities — Used in substation automation and turbine control panels requiring long-term data retention without battery backup.
Technical Specifications
| Part Number | 6ES7953-8LJ30-0AA0 |
| Manufacturer | SIEMENS |
| Product Family | SIMATIC S7-300 Micro Memory Card |
| Memory Capacity | 512 KB |
| Memory Type | Flash EEPROM (non-volatile, battery-free) |
| Compatible CPUs | S7-300 CPUs with MMC slot (CPU 312, 313, 314, 315, 316, 317, 318, 319 series) |
| Storage Content | User program (OB, FB, FC, DB), firmware updates, data logging |
| Interface | Proprietary SIMATIC MMC slot (not standard SD/MMC) |
| Operating Temperature | -20 °C to +60 °C |
| Storage Temperature | -40 °C to +85 °C |
| Write Cycles | > 100,000 (typical) |
| Data Retention | 10 years minimum (without power) |
| Dimensions | Approx. 32 × 20 × 2.1 mm |
| Weight | ~2 g |
| Certifications | CE, UL, cULus |
Why Engineers Specify This Model
- Battery-Free Retention — Flash EEPROM technology eliminates the battery-backup dependency of older S5/S7 RAM modules, reducing maintenance overhead in remote or inaccessible panel locations.
- Plug-and-Play CPU Replacement — The program resides on the card, not the CPU. Swapping a failed CPU requires only inserting the MMC into the replacement unit — no STEP 7 programmer needed on-site.
- 512 KB Headroom — Sufficient for complex S7-300 programs with multiple organization blocks, function blocks, and data blocks, including structured programs following IEC 61131-3.
- Firmware Update Carrier — Can carry CPU firmware update files, enabling field upgrades without a PG/PC connection.
- Proven Longevity — Designed for 10+ year data retention, matching the typical lifecycle of S7-300 installations in process and discrete manufacturing.
- Compact Form Factor — Fits directly into the CPU front panel slot; no additional mounting hardware or wiring required.
Complete System Bill of Materials
For a complete S7-300 control system utilizing this memory card, engineers typically specify the following components:
- Power Supply Module — e.g., 6ES7307-1BA01-0AA0 (PS 307, 2 A) or 6ES7307-1EA01-0AA0 (5 A)
- CPU Module — e.g., 6ES7314-1AG14-0AB0 (CPU 314) or 6ES7315-2EH14-0AB0 (CPU 315-2 DP)
- Micro Memory Card (this item) — 6ES7953-8LJ30-0AA0 (512 KB)
- Digital Input Module — e.g., 6ES7321-1BH02-0AA0 (SM 321, 16 DI × 24 VDC)
- Digital Output Module — e.g., 6ES7322-1BH01-0AA0 (SM 322, 16 DO × 24 VDC/0.5 A)
- Analog Input Module — e.g., 6ES7331-7KF02-0AB0 (SM 331, 8 AI)
- Interface Module — e.g., 6ES7360-3AA01-0AA0 (IM 360) for multi-rack expansion
- PROFIBUS DP Cable & Connectors — e.g., 6XV1830-0EH10 + 6ES7972-0BB52-0XA0
- DIN Rail & Mounting Hardware — Standard 35 mm DIN rail per IEC 60715
Compliance & Industry Standards
- CE Marking — Compliant with EU Low Voltage Directive and EMC Directive
- UL / cULus Listed — Recognized for use in North American industrial control panels
- IEC 61131-2 — Programmable controllers hardware requirements
- ATEX / IECEx — Compatible with S7-300 CPUs certified for Zone 2 hazardous areas (when used with appropriate CPU variant)
- RoHS Compliant — Restriction of Hazardous Substances Directive 2011/65/EU
- REACH Compliant — No substances of very high concern (SVHC) above threshold
Quality Assurance & Sourcing
At Konmask.com, every SIEMENS automation component is subject to a multi-stage verification process before dispatch:
- Authenticity Verification — Physical inspection of holographic labels, part markings, and date codes against SIEMENS genuine product references.
- Functional Pre-Test — Where applicable, MMC cards are tested for read/write integrity using SIMATIC programming tools prior to shipment.
- Traceability — Each unit is traceable to its supply chain origin; documentation available on request for regulated industries.
- Packaging Integrity — Shipped in anti-static packaging with moisture barrier; original SIEMENS blister or box preserved where available.
- Warranty — 12-month warranty against manufacturing defects; DOA replacement within 7 business days.
How to Source This Part
- Add to Cart — Click “Add to Cart” above and proceed to checkout. We accept T/T bank transfer, PayPal, and major credit cards.
- Request a Quote — For orders of 5+ units or project BOM sourcing, contact support@konmask.com for volume pricing and lead time confirmation.
- Urgent Requirements — Call or WhatsApp +0086 19859288691 for same-day quotation on critical plant-down situations.
- Export & Cross-Border Orders — We ship globally with DHL, FedEx, and UPS Express. Export documentation (commercial invoice, packing list, CO) provided for customs clearance.
- Consignment & Blanket Orders — Available for OEM and system integrators with recurring demand. Contact us to discuss stocking agreements.
Application-Specific FAQ
Q: Can this 512 KB MMC replace a 128 KB or 256 KB card in an existing S7-300 CPU?
A: Yes. The 6ES7953-8LJ30-0AA0 is backward compatible with all S7-300 CPUs that accept Micro Memory Cards. A larger capacity card will not cause errors; the CPU uses only the space required by the loaded program.
Q: Can I use this card to transfer a program from one CPU to another?
A: Yes. This is the standard SIEMENS field-replacement procedure. Insert the MMC into the source CPU, download the program to the card via STEP 7 or TIA Portal (in S7-300 compatibility mode), then insert the card into the target CPU and power on. The CPU loads the program automatically.
Q: Is this card compatible with S7-400 or S7-1200/1500 PLCs?
A: No. The S7-300 Micro Memory Card uses a proprietary interface specific to the S7-300 family. S7-400 uses a different memory card format, and S7-1200/1500 use standard SD-based SIMATIC Memory Cards (e.g., 6ES7954-8Lxxx series).
Q: What happens to the program if the MMC is removed while the CPU is running?
A: The S7-300 CPU will fault and stop. The MMC must be present during operation as it serves as the load memory. Always power down the CPU before inserting or removing the card.
Q: Can this card store data logging or recipe data in addition to the PLC program?
A: Yes, within the 512 KB capacity. Data blocks (DBs) marked as non-retentive can be stored to the MMC. For high-frequency data logging, consider a larger capacity card (e.g., 2 MB: 6ES7953-8LM31-0AA0) to avoid capacity constraints.
Q: What is the lead time for this part?
A: In-stock units ship within 1–2 business days. For out-of-stock situations, typical lead time is 5–15 business days depending on sourcing channel. Contact us for real-time availability.
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