Long-Distance Optical Communication for High-Integrity DCS Networks
The Yokogawa ANT421 Fiber Optic Bus Slave Module is a high-reliability communication interface designed to support ESB bus optical transmission in large-scale distributed control systems. As a slave-side module, it works in conjunction with a master unit to extend ESB bus signals over optical fiber, ensuring stable and noise-resistant data exchange between field control units and remote I/O nodes.
Built for demanding industrial environments, the ANT421 is widely used where long-distance communication, electrical isolation, and system redundancy are essential for continuous plant operation.
Technical Specifications
| Parameter | Specification |
|---|
| Model | ANT421 |
| Module Type | Fiber Optic Bus Slave Module |
| System Compatibility | Yokogawa CENTUM / ESB Bus / FIO systems |
| Communication Method | Optical ESB Bus |
| Function | Signal conversion: electrical ESB ↔ optical ESB |
| Maximum Transmission Distance | Up to 4 km per hop |
| Fiber Type | Multimode optical fiber (typical 50/125 µm, 62.5/125 µm) |
| Connector Type | LC connector |
| Network Topology | Chain and star configuration |
| Redundancy Support | Dual-redundant ESB bus compatible |
| Maximum Hops | Up to 8–16 hops depending on system configuration |
| Optical Loss Tolerance | ≤ 0.5 dB (typical system design) |
| Power Consumption | Approx. 0.5 A system load |
| Installation Type | FCU / FIO node unit / repeater unit rack-mounted |
| Operating Temperature | 0°C to 50°C |
| Humidity Range | 5% to 95% RH (non-condensing) |
| Dimensions (H × W × D) | Approx. 14.25 × 13.0 × 3.28 cm |
| Weight | Approx. 0.25 kg |
Application Scenarios in Industrial Systems
The ANT421 is widely used in large distributed automation infrastructures where reliable long-distance communication is required.
Typical applications include:
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Oil and gas production facilities and offshore platforms
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Petrochemical and refining plants
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Power generation and transmission systems
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Large-scale process manufacturing industries
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Remote I/O expansion and control cabinet networking
Its optical ESB architecture ensures stable communication even in environments with high electromagnetic interference or physically separated control zones.
Key Advantages and Engineering Value
One of the strongest advantages of the ANT421 is its ability to extend ESB bus communication up to 4 km per segment, enabling flexible plant layout design without compromising signal integrity.
Its optical fiber transmission design eliminates electrical noise interference, ensuring highly stable and accurate data communication in industrial environments with heavy electrical loads.
The module also supports scalable network topology (chain and star configurations), allowing engineers to design efficient distributed control architectures based on plant requirements.
In addition, its compatibility with redundant ESB bus configurations enhances system availability, making it suitable for critical process operations where continuous uptime is essential.
Technical FAQs
1. What is the main function of the ANT421?
It converts ESB bus signals into optical signals for long-distance transmission.
2. What is its maximum transmission distance?
Up to 4 km per hop in standard configuration.
3. What type of fiber does it use?
Multimode optical fiber (50/125 µm or 62.5/125 µm).
4. What systems is it compatible with?
Yokogawa CENTUM and ESB/FIO-based control systems.
5. Does it support redundancy?
Yes, it supports dual-redundant ESB bus architecture.
6. What is its role in the system?
It functions as a slave-side optical communication module.
7. What topologies are supported?
Chain and star network configurations.
8. How many hops can the system support?
Up to 8–16 hops depending on system design.
9. What ensures communication stability?
Optical transmission eliminates electromagnetic interference.
10. Where is it typically installed?
In FCU, FIO node units, or optical ESB repeater units.
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