Description

The Yokogawa SSC50D-S2521 is a rack-mountable duplexed safety control unit engineered for the ProSafe-RS Safety Instrumented System (SIS). The SSC50D-S2521 operates as a Safety Control Station (SCS) CPU node over the dual-redundant Vnet/IP control network to perform critical safety control, sequence-of-events recording (SOER), and subsystem integration functions. Certified by TÜV to meet Safety Integrity Level 3 (SIL 3) standards specified in IEC 61508, the SSC50D-S2521 delivers high-reliability execution for emergency shutdown, burner management, and safety interlock applications across process industries.

Features

• Fully redundant, duplexed architecture designed for high availability in SIL 3 safety applications.
• Integrates directly with the Vnet/IP gigabit Ethernet-based dual-redundant control network.
• Connects to safety node units (I/O nodes) via dual-redundant ESB bus interface connections.
• Supports inter-SCS safety communication over Vnet/IP to form distributed safety loops.
• Provides Modbus master/slave interface capabilities via serial or Ethernet communication modules.

Applications

• Emergency Shutdown Systems (ESD)
• Burner Management Systems (BMS)
• Fire and Gas Detection Systems (FGS)
• Process Safety Management in chemical, petrochemical, and oil & gas facilities

Technical Specifications

Installation Guidelines

• Cabinet Enclosure: For rack-mounted units to comply with safety and EMC standards, the unit must be housed in a lockable metal cabinet.
• Grounding Requirements: Provide independent grounding with a ground resistance of 100 ohms or less.
• Power Wiring Protection: Dedicated breakers conforming to applicable safety standards (such as CSA C22.2 No.5, UL 489, EN 60947-1, or EN 60947-3) must be installed in the power distribution board.
• Vnet Cable Setup: Install the specified clamp filter (A1193MN) to the Vnet communication cable as required for EMC compliance.
• ESB Bus Distance Limits: Keep the standard dedicated ESB bus cable length within 10 meters from the CPU node ports.

Compliance and Certifications

• Functional Safety: Certified SIL 3 according to IEC 61508.
• PLC Standard: Complies with IEC 61131-2.
• Application Standards: EN 54, EN 298, EN 50156-1, IEC 61511-1, IEC 62061, NFPA72, NFPA85.
• Safety Standards: CAN/CSA-C22.2 No.61010-1, EN 61010-1, EN 61010-2-030.
• EMC Standards: EN 55011 Class A Group 1, EN 61000-6-2, EN 61000-3-2, EN 61000-3-3, C-Tick Marking, KC Marking.
• Hazardous Location Certifications: FM Non-Incendive (Class I Division 2 Groups A, B, C, D T4), Type "n" (II 3 G Ex nA IIC T4 Gc / II 3 G Ex nA nC IIC T4 Gc).
• Marine Standards: ABS, BV, Lloyd's Register.