Yokogawa SSC50D-S2121 Duplexed Safety Control Unit

The Yokogawa SSC50D-S2121 Duplexed Safety Control Unit is a high-reliability component designed for use in safety instrumented systems (SIS). It ensures continuous and secure operation by providing duplexed (redundant) control, minimizing the risk of single-point failures. This control unit is primarily implemented in critical industrial processes where system safety and uninterrupted performance are of utmost importance, such as oil & gas, petrochemical, power generation, and chemical plants.

Technical Specifications

Product Applications

• Emergency shutdown (ESD) systems in oil refineries

• Burner management systems in power plants

• Process safeguarding in petrochemical complexes

• Safety control in gas processing facilities

• Chemical reactor overpressure and temperature protection

• Integrated safety system (ISS) applications in distributed control systems (DCS)

Product Advantages

• High Reliability: Duplex architecture ensures continuous operation even if one module fails.

• Safety-Certified: Designed to comply with SIL3, ensuring the highest level of safety integrity.

• Redundancy at Multiple Levels: CPU, power, and communication redundancy minimize downtime risk.

• Advanced Diagnostics: Continuous self-checking and fault isolation allow for proactive maintenance.

• Flexible Integration: Easily integrates with Yokogawa’s ProSafe-RS and other control environments.

• Scalability: Suitable for both small-scale safety systems and large-scale plant-wide safety integration.

• Extended Lifecycle Support: Built for long-term plant use with backward compatibility and vendor support.

FAQ

Q1: How does the SSC50D-S2121 handle CPU redundancy?

A1: The unit employs dual CPUs running in parallel. If one fails, the second CPU continues execution seamlessly without disrupting safety functions.

Q2: What safety standard level does the SSC50D-S2121 comply with?

A2: It is certified to SIL3 under IEC 61508, making it suitable for high-integrity safety functions.

Q3: Can the SSC50D-S2121 be integrated with ProSafe-RS?

A3: Yes, it is fully compatible with Yokogawa ProSafe-RS, enabling unified safety and process control management.

Q4: What happens if a power supply unit fails?

A4: The duplex power configuration ensures continuous operation. The system automatically switches to the redundant supply without interruption.

Q5: Does the SSC50D-S2121 support hot swapping of modules?

A5: Yes, critical modules such as power supply and CPU can be hot-swapped to minimize downtime.

Q6: What diagnostic features are available?

A6: The unit provides watchdog timers, error detection, continuous self-checking, and fault isolation to maintain system integrity.

Q7: How is communication redundancy achieved?

A7: It uses dual communication paths, ensuring that even if one network fails, the other maintains safe and reliable data transfer.

Q8: Can it be used in harsh environments?

A8: Yes, with its robust design, it supports operation in industrial temperature ranges and is resistant to vibration and electrical noise.

Q9: How is synchronization maintained between redundant CPUs?

A9: The CPUs constantly exchange state information over a high-speed internal bus, ensuring synchronized execution of safety logic.

Q10: What type of I/O modules can be connected?

A10: The SSC50D-S2121 supports Yokogawa safety I/O modules, including digital input, digital output, and analog input/output units designed for SIS applications.