Technical Overview
The Yokogawa SSC50D serves as a high-availability duplex safety control unit for critical process applications. This module provides SIL 3 certification for both IEC 61508 and IEC 61511, making it ideal for emergency shutdown systems and fire and gas detection. Its dual-redundant architecture features two independent processors operating in hot-standby mode for seamless failover. The SSC50D also includes a battery-backed real-time clock that maintains accurate time-stamping for event logs during power interruptions.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Yokogawa Electric Corporation |
| Product Type | Duplex Safety Control Unit / Logic Solver |
| System | ProSafe-RS |
| Safety Integrity Level | SIL 3 (IEC 61508 / 61511) |
| Processor Architecture | Dual-processor, hot-standby |
| Failover Time | ≤ 2 seconds |
| Scan Cycle Time | 10 ms (typical) |
| Program Memory | 4 MB Flash |
| Data Memory | 2 MB RAM |
| Retentive Data Storage | 512 KB EEPROM |
| I/O Capacity | Up to 512 points per unit |
| Communication Interfaces | 2 × Ethernet (Modbus TCP) |
| Serial Ports | 2 × RS-485 (Modbus) |
| Battery Backup | Internal lithium (10 years) |
| Power Supply | 24 VDC |
| Current Draw | 600 mA (typical) |
| Inrush Current | ≤ 5 A |
| Diagnostic LEDs | RUN, STBY, ERR, I/O, COM, FAULT |
| Dimensions (H x W x D) | 130 x 80 x 130 mm |
| Weight | 1.2 kg |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -30°C to 75°C |
| Protection Class | IP20 |
| Certifications | CE, CSA, TÜV |
Safety Architecture and Processor Redundancy
The Yokogawa SSC50D continuously synchronizes both processors during normal operation, maintaining identical program execution states. If the active unit detects a fault, the standby processor takes over control without any interruption to the safety function. This duplex configuration provides comprehensive fault coverage for memory, I/O, and communication subsystems.
Application Suitability and System Integration
This control unit supports up to 512 I/O points, accommodating large-scale safety instrumented functions across multiple plant areas. Its Ethernet interfaces enable direct connection to Yokogawa CENTUM VP DCS for integrated process safety management. Furthermore, engineers can configure the SSC50D using ProSafe-RS engineering software, simplifying logic development and system commissioning.
Diagnostics, Monitoring, and Environmental Resilience
The SSC50D provides extensive diagnostic coverage through its front-panel LEDs and integrated online monitoring tools. Its extended storage temperature range and robust construction ensure reliable operation in harsh field environments. With its substantial memory capacity and hot-standby redundancy, the SSC50D delivers exceptional availability for safety-critical installations.
Details
| Weight | 1.2 kg |
|---|---|
| Dimensions | 130 × 80 × 130 mm |
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