
Product Overview
The Yokogawa SNB10D-223/CU2N Safety Node Unit is a variant of the SNB10D series used in ProSafe-RS Safety Instrumented Systems (SIS). It functions as a distributed safety I/O node and ESB communication hub, enabling reliable field signal acquisition, power distribution, and deterministic communication between field devices and the central Safety Control Unit.
The /CU2N configuration indicates a connector unit design optimized for ESB bus connection stability, ensuring robust communication performance in redundant safety architectures.
Technical Specifications
| Parameter |
Details |
| Manufacturer |
Yokogawa |
| Model |
SNB10D-223/CU2N |
| Product Type |
Safety Node Unit |
| System Compatibility |
ProSafe-RS / SIS |
| Function |
Safety I/O node + ESB communication + power distribution |
| Communication Protocol |
ESB Bus |
| Installation |
19-inch rack mounted |
| Dimensions |
482.6 × 221.5 × 205 mm |
| Weight |
5.9 kg |
| Power Supply Options |
100–120 V AC / 220–240 V AC / 24 V DC |
| Redundancy |
Dual-redundant ESB and power architecture support |
| Operating Temperature |
-20°C to +70°C |
| Humidity |
5%–95% RH (non-condensing) |
| Country of Manufacture |
Japan |
Function and Working Principle
The SNB10D-223/CU2N operates as a distributed safety node, responsible for managing field signals and communication with the central safety controller.
Its key functions include:
- Acquisition of analog and digital field signals
- ESB bus communication with Safety Control Unit (SCU)
- Power distribution to connected I/O modules
- Supporting redundant and fault-tolerant system architecture
- Maintaining deterministic SIL-rated communication
System Data Flow
Field Devices → SNB10D Node → ESB Bus → Safety Control Unit (SCU)
This architecture ensures stable operation even under fault conditions, which is essential for safety-critical applications.
Role in Industrial Control Systems
Within Yokogawa ProSafe-RS systems, the SNB10D-223/CU2N serves as a local safety I/O hub, connecting:
- Safety transmitters (pressure, temperature, flow, level)
- Emergency shutdown switches and field contacts
- Safety digital and analog I/O modules
- Safety Control Stations (SCS)
- ESB / optical ESB network infrastructure
It helps reduce field wiring complexity while improving system scalability and maintainability.
Industrial Applications
The SNB10D-223/CU2N is widely used in:
- Safety Instrumented Systems (SIS)
- Emergency Shutdown Systems (ESD)
- Fire & Gas detection systems
- Oil and gas upstream and downstream facilities
- Petrochemical and refining plants
- Offshore platforms
- Power generation stations
- Large-scale industrial automation systems
It is particularly important in environments requiring high reliability and SIL-based safety compliance.
Installation and System Integration
Proper installation ensures stable and safe operation:
- Install in standard 19-inch industrial racks
- Ensure correct ESB bus routing and termination (/CU2N configuration)
- Maintain grounding and shielding practices
- Configure redundancy according to system architecture
- Avoid mechanical stress on connectors
- Perform full system commissioning checks
Compatible System Components
The SNB10D-223/CU2N works with:
- Yokogawa ProSafe-RS safety controllers
- ESB / optical ESB bus coupler modules (SEC401 / SEC402 series)
- Safety analog and digital I/O modules
- Terminal boards (SED / SEA / SBD series)
- Power supply modules
- Field instrumentation devices
- Engineering and maintenance stations
These components form a complete SIL-rated distributed safety architecture.
Recommended Alternative Models
| Model |
Type |
Key Feature |
Application |
| SNB10D-223/CU2N |
Safety Node Unit |
ESB connector configuration |
SIS / ESD systems |
| SNB10D-223 |
Safety Node Unit |
Standard variant |
General safety systems |
| SNB10D-215/CU2N |
Safety Node Unit |
Alternate revision |
Safety applications |
| SNB10D-213/CU2N |
Safety Node Unit |
Same platform family |
SIS systems |
| SNB10D |
Safety Node Unit |
Base platform |
General use |
Key Advantages
- SIL3-oriented safety system architecture
- Reliable ESB communication with redundant design
- Stable connector configuration (/CU2N)
- Supports distributed I/O architecture
- Integrated power distribution for modules
- Strong diagnostics and fault detection
- Suitable for 24/7 continuous operation
- Reduces field wiring complexity
- Proven performance in harsh environments
Technical FAQs
What is SNB10D-223/CU2N used for?
It is used as a safety node unit in Yokogawa ProSafe-RS systems for field signal acquisition and ESB-based communication.
Is it a controller or CPU?
No. It is a distributed safety I/O node, not a processing unit.
What does “/CU2N” mean?
It refers to a connector unit configuration designed for ESB bus connection stability.
What system uses it?
It is used in Yokogawa Safety Instrumented Systems (SIS), including ESD and F&G applications.
Conclusion
The Yokogawa SNB10D-223/CU2N Safety Node Unit is a critical component in industrial safety automation systems. It provides reliable field signal acquisition, ESB communication, and power distribution within a redundant safety architecture. Its robust design and SIL-oriented performance make it suitable for demanding industrial environments requiring high safety integrity and continuous operation.