
Product Overview
The Yokogawa SNT401-13 is a Fiber Optic ESB Bus Repeater Main Module used in ProSafe-RS Safety Instrumented Systems (SIS). It is designed to convert electrical ESB bus signals into optical signals, enabling long-distance and high-reliability communication between safety controllers, safety node units, and distributed I/O systems.
The “-13” variant is a specific model configuration within the SNT401 series used for optical ESB communication extension in industrial safety networks.
Technical Specifications
| Parameter |
Details |
| Manufacturer |
Yokogawa |
| Model |
SNT401-13 |
| Product Type |
Optical ESB Bus Repeater Main Module |
| System Platform |
ProSafe-RS SIS |
| Function |
ESB electrical-to-optical signal conversion |
| Communication Type |
Fiber Optic ESB Bus |
| Mounting Type |
19-inch rack mounted |
| Dimensions |
142.5 × 130 × 32.8 mm |
| Weight |
0.3 kg |
| Configuration |
Master-side repeater module |
| System Role |
Optical ESB communication extension |
Function and Working Principle
The SNT401-13 functions as a communication interface module that extends ESB bus networks using fiber optics.
Key functions include:
- Converts ESB electrical signals into optical signals
- Extends communication distance between SIS components
- Maintains signal integrity in large-scale systems
- Supports redundant and distributed safety architectures
- Works in combination with SNT501 slave module
System Flow
Safety Controller / SNB10D Node → ESB Bus → SNT401-13 → Fiber Optic Cable → SNT501 → Remote Safety Node
System Role
The SNT401-13 acts as the master-side optical repeater module in Yokogawa ESB network architecture. It is typically installed near:
- Safety controllers
- ESB bus coupler modules
- Central control cabinets
It enables communication with remote safety nodes over long distances using fiber optics.
Industrial Applications
- Oil & gas facilities
- Petrochemical plants
- Refinery systems
- Offshore platforms
- Power generation stations
- Chemical processing plants
- Safety Instrumented Systems (SIS)
- Emergency Shutdown Systems (ESD)
- Fire & Gas detection systems
Installation Notes
- Installed in standard 19-inch control racks
- Must be used with SNT501 slave module
- Fiber optic cabling required for communication link
- Must follow ESB system design rules
- Proper grounding required for system stability
Compatible Components
- SNT501 Optical ESB Bus Repeater Slave Module
- SNB10D Safety Node Units
- SEC401 / SEC402 ESB Bus Coupler Modules
- SSB401 ESB Interface Modules
- ProSafe-RS safety controllers
- Fiber optic ESB cabling systems
Alternative / Related Models
- SNT401 (standard variant)
- SNT401-13 (this model)
- SNT501 (slave module)
- SNT10D repeater unit system
- SEC401 / SEC402 ESB coupler modules
Key Advantages
- Enables long-distance ESB communication
- High immunity to electromagnetic interference
- Supports fiber optic industrial networking
- Suitable for large distributed SIS systems
- Improves system scalability and flexibility
- Compatible with redundant safety architectures
FAQ
Q: What is SNT401-13 used for?
It is used to convert ESB electrical signals into optical signals for long-distance communication.
Q: Does it work alone?
No. It must be paired with an SNT501 slave module.
Q: Is it a control processor?
No. It is a communication repeater module, not a CPU or controller.
Conclusion
The Yokogawa SNT401-13 Fiber Optic ESB Bus Repeater Module is a key communication component in ProSafe-RS safety systems. It enables reliable long-distance ESB network extension using fiber optics, ensuring stable and scalable connectivity in large industrial safety architectures.