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Product Introduction
The Yokogawa AFS20S Field Control Unit is a powerful, compact, and highly reliable component in Yokogawa’s CENTUM VP distributed control system (DCS) platform. Designed to deliver real-time control and monitoring in large-scale industrial processes, the AFS20S serves as a critical unit that executes control logic, manages field I/O, and communicates with supervisory systems.
This unit integrates advanced hardware performance with high-speed processing capabilities, offering users fast response times and uninterrupted data processing. It supports dual-redundancy configurations, hot-swapping, and features Yokogawa’s proven pair & spare architecture, ensuring high availability in mission-critical environments. With flexible scalability and tight integration with other CENTUM VP components, the AFS20S is ideally suited for oil & gas, petrochemical, power, and water treatment facilities.
Product Specifications
| Parameter | Specification |
|---|---|
| Product Name | AFS20S Field Control Unit |
| System | CENTUM VP (Distributed Control System) |
| CPU | Dual-redundant control processors (Pair & Spare configuration) |
| Memory | 64 MB DRAM (per CPU) |
| Flash ROM | 16 MB (per CPU) |
| Control Cycle | 100 ms (standard); configurable |
| Communication Interfaces | Vnet/IP (1 Gbps), Fieldbus, Ethernet |
| Redundancy Support | Yes – CPU, Power Supply, Communication |
| Number of Control Loops | Up to 2,000 loops |
| I/O Module Support | Supports FIO (Field I/O) via ESB bus or Vnet/IP |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -20°C to +70°C |
| Humidity | 5% to 95% RH (non-condensing) |
| Power Supply | 24 V DC ±10% |
| Power Consumption | Approx. 20 W per module |
| Mounting Method | Mounted in N-IO or standard system rack |
| Dimensions (W × H × D) | 207 × 265.9 x 482.6 mm |
| Weight | 8 kg |
| Certifications | CE, CSA, ATEX, UL, FM, IECEx |
| Compatible Software | CENTUM VP R6 and later versions |
Applications
The Yokogawa AFS20S is deployed in diverse industrial sectors where real-time process control, high reliability, and safety compliance are paramount. Typical applications include:
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Oil & Gas: Used for control of upstream, midstream, and downstream operations including refineries.
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Chemical and Petrochemical Plants: For batch and continuous processing.
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Power Generation: Applied in thermal, hydro, and nuclear control systems.
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Water & Wastewater Treatment: Supports SCADA and DCS-based automation.
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Pulp & Paper: For distributed automation of paper machines and chemical recovery.
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Pharmaceutical Manufacturing: Ensures precision and repeatability for GMP compliance.
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Metals and Mining: Used in process automation and control of smelting and refining.
Product Advantages
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High Availability Architecture: The Pair & Spare configuration ensures continuous operation even if one processor fails.
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Hot Swap Capabilities: Modules can be replaced during operation without system shutdown, reducing downtime.
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Flexible and Scalable: Can easily be integrated into small to large-scale systems with thousands of control loops.
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Fast Control Cycle: Supports rapid loop updates for time-sensitive process control.
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Fieldbus and Ethernet Ready: Seamless communication with smart field instruments via FOUNDATION™ Fieldbus or Ethernet/IP.
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Long Lifecycle Support: Yokogawa’s DCS systems are known for long-term availability and backward compatibility.
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Efficient Power Usage: Low power design minimizes heat and energy consumption.
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Robust Design: Operates reliably under a wide range of environmental conditions with industrial-grade protection.
Frequently Asked Questions (FAQ)
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What is the main function of the AFS20S in a CENTUM VP system?
The AFS20S functions as the field control unit that executes control strategies and interfaces with I/O modules in real-time. -
Does the AFS20S support redundant CPUs?
Yes, it features dual-redundant CPUs operating in a Pair & Spare configuration for fault tolerance. -
How many control loops can a single AFS20S manage?
It can handle up to 2,000 PID control loops depending on configuration and system design. -
Can modules be replaced while the system is running?
Yes, the AFS20S supports hot-swapping of CPU and I/O modules without interrupting the control process. -
Is the AFS20S compatible with legacy Yokogawa systems?
It is compatible with CENTUM VP systems and supports integration with previous CENTUM CS systems with proper configuration. -
What type of I/O connections does the AFS20S support?
It supports both direct Field I/O (FIO) and remote I/O through Ethernet-based connections or ESB bus. -
What environments is the AFS20S certified for?
It is certified for use in hazardous environments with approvals including ATEX, IECEx, UL, and CSA. -
What is the typical lifespan of the AFS20S?
Yokogawa offers support and parts for up to 15–20 years, ensuring long-term system sustainability. -
How is communication handled in the AFS20S?
It uses Vnet/IP, a 1 Gbps real-time network for high-speed and reliable communication within the control system. -
Can the AFS20S be used in safety instrumented systems (SIS)?
While the AFS20S itself is not SIL-certified, it can operate in parallel with Yokogawa’s ProSafe-RS system for safety integration.
Related Models (Same Series or Function)
| Model | Description | Control Capacity | Communication |
|---|---|---|---|
| AFV10D | Compact Field Control Unit for small-scale systems | Up to 500 loops | Vnet/IP |
| AFF50S | High-performance Field Control Station | Up to 10,000 loops | Vnet/IP, FF |
| FCS20D | Standard Field Control Station for CS 3000 | Moderate loop control | Vnet/IP |
| VJ71 | Field I/O Rack for remote installations | Supports various I/O | ESB Bus |
| S2FCU | Redundant Safety Control Unit (for ProSafe-RS) | SIL 3 capable | Vnet/IP |
| FCN-500 | Modular PLC/DCS hybrid for edge control | Small/mid applications | Ethernet/IP |
Popular Yokogawa Models (Same Brand)
| Model | Category | Main Function | System Integration |
|---|---|---|---|
| ProSafe-RS | Safety Instrumented System | SIL-rated emergency shutdown control | Integrates with CENTUM VP |
| STARDOM FCN-RTU | Remote Terminal Unit | Edge computing and control for remote sites | SCADA, IoT |
| YTA610 | Temperature Transmitter | Accurate field temperature measurements | FOUNDATION Fieldbus |
| EJX530A | Pressure Transmitter | High-performance pressure monitoring | HART/Fieldbus |
| DX2020 | Paperless Recorder | Data logging and process monitoring | Ethernet |
| GX20 | Smart Data Acquisition System | High-speed data recording | Web & network access |
