Yokogawa SSC50D-S2121 Duplexed Safety Control Unit

The Yokogawa SSC50D-S2121 Duplexed Safety Control Unit provides reliable safety control performance in complex automation systems. Although Yokogawa stopped production of this model, engineers can choose the new replacement SSC50D-S2E21 for future installations.

Product Overview

The SSC50D-S2121 uses a powerful MIPS R5000 processor and 32 MB of memory to manage safety-critical applications. It stores programs in flash memory while preserving operational data in nonvolatile NVRAM. Engineers can depend on its stable performance and high fault tolerance in demanding industrial environments.

Technical Specifications

Parameter	Value
Product No.	SSC50D-S2121
Manufacturer	Yokogawa
Product Type	Duplexed Safety Control Unit
Processor	MIPS R5000
Main Memory Capacity	32 MB
Program Storage	Flash memory
Operation Data Storage	NVRAM (nonvolatile memory)
Temperature Adaptability	Fan unit supports ambient >40 °C
Communications Interface	Dual-redundant Vnet/IP and ESB bus
Communication Speed	100 Mbps, full duplex
Cable/Connector	UTP CAT5e+, RJ45, 100BASE-TX compliant
Max Cable Distance	100 m (unit to Layer 2 switch)
Safety Node Units	Up to nine per unit
I/O Modules Supported	Up to eight per unit, 78 per SCS
Power Requirements	100–120 V AC, 220–240 V AC, or 24 V DC
Power Consumption (S model)	200 VA (AC 100–120 V), 230 VA (AC 200–240 V), 5.5 A (24 V DC)
Power Consumption (F model)	240 VA (AC 100–120 V), 290 VA (AC 200–240 V), 7.0 A (24 V DC)
Weight	8.5 kg

Origin

Yokogawa manufactures the SSC50D-S2121 in Japan, ensuring precision engineering and compliance with global automation standards.

Dimensions and Weight

The safety control unit weighs 8.5 kg, giving engineers a balance of strength and manageability during installation and servicing.

Communication and Connectivity

The SSC50D-S2121 supports dual-redundant Vnet/IP and ESB bus communication. It connects through UTP CAT5e or higher cables with RJ45 connectors, ensuring secure data transmission. The system achieves 100 Mbps full-duplex communication over distances up to 100 meters.

Expandability

Each SSC50D-S2121 connects up to nine safety node units, and engineers can mount ESB bus coupler modules (SEC401) on the 7th and 8th slots. Optical ESB bus repeater modules extend communication capabilities for larger installations.

Applications

The Yokogawa SSC50D-S2121 Duplexed Safety Control Unit supports safety control in critical industries:

Oil & Gas – Reliable shutdown systems for hazardous environments.
Power Generation – High redundancy ensures continuous plant safety.
Chemical Processing – Precise safety logic control in complex processes.

Why Choose Yokogawa SSC50D-S2121

Engineers select the SSC50D-S2121 for its proven reliability, dual redundancy, and robust architecture. Since Yokogawa now recommends the SSC50D-S2E21 as its official replacement, users can migrate smoothly while keeping system compatibility.