Product Overview
The 6ES5375-0LD31 is a SIMATIC S5 375-series memory submodule manufactured by Siemens, delivering 32 KB of battery-backed CMOS RAM for user programs and data blocks in S5-115U, S5-135U, and S5-155U controllers. As a member of Siemens’ renowned 6ES5375 memory submodule family, the 6ES5375-0LD31 plugs directly into the dedicated memory slot of compatible S5 CPUs, providing the volatile yet high-speed storage workspace that makes online program modification, parameter tuning, and iterative debugging possible without the slow erase-and-burn cycle required by EPROM variants. Weighing just 0.05 kg and measuring to the DIN 41494 Euro-card standard, the 6ES5375-0LD31 is a genuine German-made Siemens original (EAN 4025515053255, commodity code 85389091) that has become a strategically critical MRO spare for factories still running SIMATIC S5 automation decades after the platform’s discontinuation.
Unlike EPROM-based siblings that demand ultraviolet erasure or specialized programmers, the 6ES5375-0LD31 allows engineers to download, edit, and re-download STEP 5 code on the fly — a capability that makes it the preferred choice for machine commissioning, process tuning, and temporary program expansion. Data integrity on the 6ES5375-0LD31 is maintained by the CPU’s backup battery; with a healthy battery, the 32 KB RAM contents survive power cycles and brief outages. This battery-dependent architecture is precisely why the 6ES5375-0LD31 shines in development and debugging phases, where rapid program changes matter more than permanent, power-independent storage. For long-term program archiving, the same 6ES5375 family offers EEPROM and EPROM variants — but for the day-to-day engineering workflow on a live S5 system, the 6ES5375-0LD31 is unmatched in convenience.
Siemens has long since placed the 6ES5375-0LD31 at the end of its product lifecycle (listed as “End of Product Lifecycle”), and the module is not RoHS-compliant per current EU directives — a characteristic shared by all legacy S5 memory submodules. Nevertheless, professional automation suppliers continue to overhaul, fully test, and warranty the 6ES5375-0LD31, with leading distributors offering up to 24-month warranty coverage and complete functional verification prior to shipment. For the thousands of S5-115U/135U/155U installations still governing critical processes in power plants, steel mills, chemical facilities, and manufacturing lines worldwide, the 6ES5375-0LD31 remains the authentic, drop-in memory solution — preserving the substantial embedded value of validated STEP 5 codebases and protecting plants from the six-figure cost of a full PLC platform migration.
Technical Specifications
| Parameter | Value |
|---|---|
| Product Model | 6ES5375-0LD31 |
| Manufacturer | Siemens AG |
| Product Type | SIMATIC S5 375 Memory Submodule (RAM) |
| Product Family | SIMATIC S5 (6ES5375 Memory Submodule Series) |
| Storage Capacity | 32 KB (32 KBytes) |
| Memory Type | CMOS RAM (volatile, battery-backed) |
| Compatible Controllers | SIMATIC S5-115U, S5-135U, S5-155U |
| Data Retention | Battery-backed via CPU backup battery |
| Working Voltage | 5 V DC (from CPU backplane) |
| Write Operation | Online modifiable via STEP 5 (no erase/burn cycle) |
| Read Speed | High-speed, matched to CPU scan cycle |
| Erase Method | Software erase; data lost on battery depletion |
| Mounting Method | Plugs into dedicated memory submodule slot of S5 CPU |
| Form Factor | DIN 41494 Euro-card submodule |
| Operating Temperature | 0 °C to +60 °C |
| Storage Temperature | -40 °C to +70 °C |
| Protection Rating | IP20 (when installed in CPU) |
| Dimensions (L × W × H) | 9.50 × 6.20 × 2.20 cm (packaging) |
| Net Weight | 0.05 kg |
| EAN | 4025515053255 |
| Commodity Code | 85389091 |
| RoHS Compliance | Not RoHS-compliant (legacy class) |
| Lifecycle Status | End of Product Lifecycle (Siemens official) |
| Country of Origin | Germany |
