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Technical Overview of the S7-300 Fail-Safe CPU
The Siemens 6ES7317-6FF00-0AB0 central processing unit functions as a fail-safe controller within the SIMATIC S7-300 automation system. This CPU executes standard and safety-related programs simultaneously on a single hardware platform. Its integrated PROFIBUS DP interface enables high-speed communication with distributed I/O stations. The module also supports fail-safe communication via PROFIsafe for safety-critical applications. Consequently, this CPU delivers both standard automation and machine safety functions in one compact unit.
Key Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | Siemens |
| Model Number | 6ES7317-6FF00-0AB0 |
| Product Type | Central Processing Unit (Fail-Safe CPU 317F) |
| Compatible System | SIMATIC S7-300 |
| Safety Class | SIL 3 (IEC 61508), PL e (ISO 13849-1) |
| Work Memory (Program) | 512 KB (integrated) |
| Work Memory (Data) | 256 KB (integrated) |
| Load Memory Capacity | 2 MB (expandable via MMC) |
| Processing Time (Bit) | Approx. 0.05 µs |
| Processing Time (Word) | Approx. 0.2 µs |
| Integrated Interface | PROFIBUS DP (DP master, 12 Mbps) |
| PROFIsafe Support | Yes (fail-safe communication) |
| Digital Inputs (Integrated) | None (requires external modules) |
| Power Consumption | Approx. 350 mA (from backplane) |
| Operating Temperature | 0°C to +60°C |
| Dimensions (W x H x D) | 80 mm x 125 mm x 130 mm |
| Weight | Approximately 0.5 kg |
| Protection Class | IP20 |
| Certifications | CE, UL, CSA, ATEX, IEC 61508 |
Functional Capabilities and Design Features
This CPU features a high-speed bit instruction execution time of just 0.05 microseconds. Its built-in PROFIBUS DP interface supports up to 32 slaves per network segment. The module also includes a real-time clock for time-stamping safety events. Furthermore, its integrated safety program runs independently from the standard user program. Therefore, this CPU ensures reliable machine safety without compromising standard control performance.
Engineering and Application Context
The Siemens 6ES7317-6FF00-0AB0 CPU operates with the S7-300 rail mounting system. Engineers program the safety functions using S7 Distributed Safety or S7 F Systems software. The MMC slot provides flexible memory expansion for large-scale projects. Ultimately, this CPU offers a cost-effective solution for integrating safety into standard automation systems.