Description
1. Product Overview
YOKOGAWA AFV30D-A41152 is a redundant Field Control Unit (FCU) for the CENTUM VP Distributed Control System (DCS). As the core process controller of the FIO Field Input/Output architecture, it adopts a dual-CPU hot standby hardware redundant design. It independently executes industrial control calculations including continuous process regulation, sequential logic control, batch program control and interlock protection. It collects field analog (AI) and digital (DI) signals, executes PID and sequence control algorithms, and outputs AO/DO control commands to drive actuators. Meanwhile, it realizes real-time data exchange with human-machine operating stations, process gateways and third-party PLC/DCS systems via the control bus.
Equipped with a high-performance multi-core processor, large-capacity program storage and high-speed I/O scanning capability, this model features a triple fault-tolerant architecture consisting of redundant power supplies, redundant control CPUs and redundant communication buses. It enables bumpless automatic master-standby switching upon faults, making it suitable for high-safety continuous production facilities in chemical, power, metallurgy, oil & gas, pharmaceutical and other industries. It can be deployed as control station hardware for new CENTUM VP control systems, and also serves as a spare replacement for legacy redundant FCU controllers of the same series as well as for system hardware expansion and upgrading.
2. Hardware Structure and Composition
2.1 Dual Redundant CPU Main Control & Operation Unit
It adopts a primary-standby dual-processor hardware redundant architecture. The two CPUs run completely independently and in parallel, synchronizing all control programs, process parameters, interlock logic and internal register data in real time. When the primary controller suffers hardware failure, program abnormality or communication interruption, the standby CPU takes over all control tasks within milliseconds with bumpless switching, avoiding control output fluctuations and false trips of process interlocks. Built with a high-speed process operation kernel, it supports multi-loop PID regulation, feedforward control, fuzzy control, batch recipe control, sequential control and SIS safety interlock logic calculation. A single controller can host hundreds of control loops to meet the centralized control requirements of large-scale process plants. The main control board integrates hardware watchdog, power supply voltage monitoring and temperature detection circuits, which automatically latch fault codes upon abnormalities and trigger local alarms as well as fault upload to the upper system.
2.2 FIO Bus I/O Communication Interaction Unit
It connects remote FIO terminal modules through a dedicated FIO field bus, supporting star and tree topologies. Multiple groups of remote I/O nodes can be connected to one FIO bus with a maximum transmission distance of several kilometers, realizing a distributed wiring mode where controllers are centrally installed in the control room and I/O modules are deployed locally on site. Adopting electrical isolation and CRC data check mechanisms, the bus resists electromagnetic interference from plant frequency converters and high-voltage equipment. Bus short-circuit or single I/O node faults will not shut down the entire FCU controller; only faulty points are isolated to ensure normal operation of other control loops. The controller is equipped with dual redundant Vnet/IP industrial Ethernet interfaces for process control network to realize real-time data interaction with operator stations, servers and other FCU control stations.
2.3 Redundant Power Supply & Status Indication Unit
The device accepts two independent 24VDC redundant power inputs operating in hot standby mode. If one power supply fails or experiences abnormal voltage, the other provides seamless uninterrupted power supply to prevent control station shutdown caused by single-point power faults. The front panel is fitted with multiple LED indicators for master/standby operation, bus communication, power fault, hardware alarm and program running status, enabling on-site visual checking of master-standby mode, bus link status and hardware fault locations. A non-volatile flash memory on the board permanently stores all control configuration programs, process parameters, fault events and historical operation logs even after power failure, preventing loss of control logic caused by unexpected power outages.
2.4 19-inch Standard Rack Mounting Unit
Designed for horizontal installation on standard 19-inch industrial rack guide rails, the whole device adopts a modular pluggable structure. The CPU board, power module and bus communication board can be hot-swapped individually (hot swapping of the primary CPU during operation is prohibited). Strong and weak current circuits are physically routed separately with dedicated terminals for power, communication and grounding, together with a special shielded grounding terminal block to effectively suppress common-mode interference. Backward compatible with hardware of the same series, it can directly replace legacy AFV30D redundant control units on-site without modifying the original FIO bus topology and control configuration programs, greatly shortening the commissioning period of technical renovation projects.
3. Technical Specifications
3.1 Electrical Specifications
- Power Supply: Dual redundant 24VDC (20.4~28.8VDC), maximum power consumption of each channel: approx. 65W
- Control Performance: Minimum process control scan cycle: 10ms; maximum 500 PID control loops and 2000 sequence control steps per unit
- Communication Interfaces: Dual redundant Vnet/IP Gigabit industrial Ethernet; dual redundant FIO field control bus
- Redundancy Mode: Triple hardware hot redundancy for CPU, power supply and control bus; fault switching time ＜20ms with bumpless control output
- Storage: Program flash memory ≥1GB, supporting local mass storage of process parameters, fault events and operation logs
- Configuration Mode: Offline configuration, program download, online parameter modification and program upload via the CENTUM VP system engineer station
3.2 Environmental Specifications
- Operating Temperature: 0℃~+50℃; Storage & Transportation Temperature: -20℃~+70℃; derating required for altitudes above 2000m
- Relative Humidity: 5%~90% RH, non-condensing, free of corrosive gas and conductive dust; environmental class: 3K3
- EMC Compliance: IEC 61000 Industrial Class A, resistant to ESD, surge and electrical fast transient burst interference
- Protection Class: IP20, for installation only in indoor enclosed and ventilated industrial control cabinets
3.3 Mechanical Specifications
- Mounting Method: Horizontal fixed installation on standard 19-inch industrial racks
- Overall Dimensions: W 482.6mm × D 265.9mm × H 207mm
- Net Weight: Approx. 8.0kg
- Cooling Mode: Natural convection cooling, fanless, low-noise and maintenance-free design
- Optional Accessories: FIO remote I/O modules, Vnet/IP switches, system engineering configuration software, shielded communication cables, redundant power supply modules
4. Product Functions and Features
4.1 Triple Hardware Redundant Fault-tolerant Architecture Ensures Uninterrupted Continuous Production
Dual hot standby redundancy is adopted for CPU, power supply and control bus. In case of any hardware, link or power fault, the system switches automatically within milliseconds with bumpless control output and no false process interlock actions, avoiding unplanned plant shutdown due to single-point hardware failures. It is perfectly suitable for 24/7 high-risk continuous production scenarios such as petroleum refining, fine chemical industry and thermal power plants.
4.2 Rich Process Control Algorithm Library Meets Diverse Control Requirements for Complex Processes
It embeds hundreds of standard industrial control algorithms including PID, PD, feedforward control, lag compensation, batch control, sequential control, equipment interlock, flow accumulation, temperature and pressure compensation, and supports programming of custom advanced control modules. It realizes precise closed-loop regulation for complex processes such as distillation, reaction, heating and compression, covering both continuous process control and intermittent batch production control applications.
4.3 Distributed FIO Remote I/O Architecture Optimizes Field Wiring and Reduces Interference Risks
FIO field bus allows I/O modules to be installed locally in field junction boxes. Only one pair of bus communication cables is laid from the control room, greatly reducing the wiring workload of long-distance analog and digital cables, and eliminating voltage attenuation and electromagnetic crosstalk caused by long-distance weak signal transmission. A single bus fault only isolates local I/O points without affecting the overall plant control operation.
4.4 Comprehensive Fault Diagnosis and Event Traceability Facilitate Operation & Maintenance Troubleshooting
It monitors the full-link hardware status of CPU, power supply, FIO bus, I/O modules and communication links in real time, automatically latching fault time, location and type once faults occur. Tens of thousands of operation records, interlock actions and hardware alarms are stored locally. Historical logs can be retrieved via the upper engineer station to quickly identify root causes of process abnormalities, hardware faults and misoperations, meeting compliance audit requirements for safe production.
4.5 Online Bumpless Download and Remote Operation & Maintenance Enable Configuration Optimization Without Plant Shutdown
It supports online bumpless download and modification of control programs and process parameters, allowing tuning of control loop parameters, optimization of sequence logic and revision of interlock conditions without stopping the plant. The Vnet/IP control network enables remote online commissioning, fault diagnosis and program backup via engineer stations, significantly reducing on-site maintenance trips and plant commissioning downtime.
4.6 Industrial-grade Maintenance-free Hardware Design Ensures Long-term Stable Operation in Harsh Plant Environments
The fanless natural convection cooling architecture eliminates controller overheating shutdown failures caused by fan aging or stalling. PCBs are coated with three-proof conformal coating to withstand harsh on-site conditions including dust, humidity and industrial electromagnetic interference, with an MTBF (Mean Time Between Failures) of several decades. Stable long-term operation can be guaranteed by regular inspection of wiring tightness and cabinet temperature & humidity.
5. Applicable Working Conditions and Application Scenarios
- Deployment of core process control stations for CENTUM VP DCS systems in continuous production plants of petroleum refining, coal chemical and fine chemical industries, realizing closed-loop regulation and safety interlock control for distillation columns, reactors, furnaces and compressors.
- Distributed control for boilers, steam turbines and auxiliary water treatment systems in thermal power and biomass power plants, enabling automatic regulation of temperature, pressure, liquid level and flow as well as equipment protection interlocks.
- Intermittent batch production lines in pharmaceutical, food, water treatment and metallurgical industries, realizing automatic process control and process parameter traceability via sequence control and batch recipe functions.
- Hardware upgrading of legacy CENTUM VP control systems by upgrading single-CPU control stations to AFV30D redundant FCUs to improve system fault tolerance and plant safety level.
- Spare replacement of faulty AFV30D control units of the same series and deployment of new control stations for I/O measuring point expansion of FIO architecture control systems.
