Product Overview

The Yokogawa SNT501-13 is a high-performance Optical ESB Bus Repeater Module designed to facilitate long-distance communication within the ProSafe-RS safety instrumented system (SIS) and CENTUM VP environments. This module acts as a specialized fiber optic interface that extends the Extended Serial Backplane (ESB) bus beyond the limitations of standard copper cabling. By converting electrical bus signals into optical signals, the SNT501-13 allows for the connection of remote I/O nodes over distances of up to 5 kilometers.

Primarily utilized in large-scale industrial facilities, this module ensures that safety-critical data is transmitted with ultra-low latency and high integrity. The use of fiber optic media provides total galvanic isolation and immunity to electromagnetic interference (EMI) and radio frequency interference (RFI), which is essential for maintaining stable communication in high-voltage environments such as power substations and heavy manufacturing floors.

Technical Specifications

• Manufacturer: Yokogawa

• Model Number: SNT501-13

• Module Type: Optical ESB Bus Repeater (Master Side)

• Transmission Speed: 128 Mbps

• Transmission Distance: Maximum 5 km (using 50/125 μm GI optical fiber)

• Interface Type: Optical Fiber (LC Connector)

• Network Topology: Star or Chain configuration

• Power Consumption: Max 0.5 A (5 V DC)

• Redundancy: Supports dual-redundant configuration for mission-critical safety

• Operating Temperature: 0 to 50°C (Standard industrial range)

• Dimensions: 32.8 mm x 106.3 mm x 130 mm

• Weight: 0.30 kg

• Origin: Japan

Key Operational Characteristics

• High-Bandwidth Safety Communication: Operates at a dedicated 128 Mbps transfer rate, ensuring that safety logic execution and emergency shutdown signals are processed within strictly defined time constants.

• Advanced Redundancy Architecture: Supports synchronous dual-redundant bus configurations. In the event of a fiber break or module fault, the system triggers an instantaneous, bumpless switchover to the secondary path to maintain safety system availability.

• Electromagnetic Immunity: The optical transmission method eliminates ground loops and protects the control network from lightning-induced surges or industrial noise, making it ideal for outdoor-to-indoor cabling.

• Long-Range Remote I/O Support: Enables the distribution of Field Control Stations (FCS) and I/O nodes across expansive sites, such as offshore platforms, refineries, and tank farms, without compromising signal quality.

• Intelligent Diagnostics: Integrated self-monitoring features detect optical signal degradation or synchronization errors, providing early warning alerts to the maintenance workstation before a communication failure occurs.

• Seamless ProSafe-RS Integration: Designed to plug directly into the ESB bus master slot, requiring minimal software configuration for full system transparency.