Description
1. Product Overview
ABB PM858AK02 (Part No.: 3BSE082896R1) is a high-end redundant CPU controller module of the AC800M series developed by ABB, Switzerland. It is compatible with ABB Ability™ System 800xA integrated automation control system and serves as the core computing and control hub of DCS systems for process industries. As the upgraded high-spec K02 variant, this module adopts a high-performance industrial MPC866 processor, integrated with large-capacity program and data storage, dual-Ethernet redundant communication, high-speed bus scheduling, full-system logic operation and fault self-diagnosis functions. It is designed for high-reliability, non-stop and high real-time production conditions in large-scale process industries.
PM858AK02 natively supports dual CPU hot-standby architecture to realize bumpless master-backup switching. Together with original accessories including TP830 base unit, TB807 bus terminator and TK850 extension cable, it forms a complete control unit. The module is compatible with the full range of S800 I/O modules. Relying on CEX high-speed extension bus and ModuleBus bus, it enables large-scale point management, closed-loop control of complex processes, equipment interlock protection and plant-wide data communication interaction. Certified against strict explosion-proof, marine and EMC standards, it fits high-risk continuous production scenarios such as chemical, oil & gas, power, metallurgy and water treatment industries. It is widely adopted in turnkey projects of new 800xA DCS systems, computing capacity upgrade of legacy AC800M control stations, redundant system renovation and replacement of faulty spare parts, acting as the primary core CPU unit for industrial distributed control systems.
2. Technical Features
2.1 High-End Industrial Processor with Powerful Computing Capacity for Complex Processes
Equipped with an industrial dedicated MPC866 processor featuring excellent main-frequency computing performance, it delivers high-speed logic operation, floating-point calculation and batch data processing capability. It efficiently handles high-density computing tasks including large-scale PID closed-loop regulation, complex equipment interlocks, precise timing scheduling and batch process control. Optimized operation logic is adopted for multi-loop, variable-load and frequent process switching conditions of large plants to eliminate calculation delay, logic stalling and timing deviation. It ensures millisecond-level response and high-precision control of complex process systems and fully meets stringent automation control requirements of large process industries.
2.2 High-Spec Storage Architecture for Stable Mass Data Retention
It adopts dedicated partition storage for programs and data, equipped with large-capacity non-volatile program storage and high-speed operating cache. It supports permanent storage of user control programs, process recipes, interlock logic and system configuration parameters. Supported by ABB original battery-backed power-fail protection mechanism, operating logs, time-sequence fault data and process trend parameters can be completely retained after power loss, preventing parameter loss, program failure and system reset upon restart. It satisfies demands of long-term continuous industrial production and process data tracing, enabling complete local data storage without external storage devices.
2.3 Dual-Ethernet Redundant Communication for High-Speed and Stable Networking
Two independent industrial Ethernet ports are integrated to support redundant networking architecture, realizing high-speed data exchange with upper 800xA monitoring system, operator stations, servers and third-party intelligent equipment. The two network links back up each other; single-link failure will not affect overall system communication, fundamentally avoiding risks of process runaway and data interruption caused by network outage. Meanwhile, built-in high-speed CEX extension bus and ModuleBus local I/O bus realize millisecond-level I/O signal acquisition and synchronous issuance of control commands to guarantee accurate linkage of distributed control nodes across the plant.
2.4 Native Dual Redundant Hot-Standby for Uninterrupted Production Control
The module supports a complete CPU hot-standby redundancy scheme. Master and backup CPUs run in parallel and synchronously, mirroring program logic, process parameters, operating conditions and cached data in real time. When the primary CPU suffers hardware failure, communication interruption, computing abnormality or power fluctuation, the system can perform automatic bumpless, non-stop switching without process fluctuation. The standby CPU seamlessly takes over all control tasks without interrupting production processes or changing equipment operating status. It thoroughly solves plant shutdown, production interruption and process fluctuation risks induced by single CPU faults, suitable for 7×24-hour continuous high-risk production conditions.
2.5 Standardized Configuration Programming with Excellent Compatibility and Expandability
Fully compatible with ABB 800xA Control Builder official configuration software and IEC industrial control programming standards, it supports multiple programming modes including ladder diagram, function block diagram and structured text for customized process logic, control loops and interlock strategies. Natively compatible with full-series AC800M controller hardware, S800 I/O modules and 800xA system architecture, it seamlessly connects new and legacy systems and supports online program modification, parameter downloading, logic debugging and signal point expansion. Analog, digital, safety interlock and communication expansion units can be flexibly added to build distributed control systems of various scales for different process technical transformation and system upgrading projects.
2.6 Full-Dimension Self-Diagnosis and Fault Tolerance for Elevated System Safety
Embedded with full-dimension self-diagnosis mechanism covering hardware, software, bus, communication and data, it monitors various fault conditions in real time such as CPU computing abnormality, storage failure, Ethernet link disconnection, CEX bus anomaly, power fault, program error and I/O loop abnormality. It accurately locates fault points and automatically records time-sequence fault logs and error codes. Fault-tolerant calculation is available for minor abnormal conditions; system alarms, fault recording and redundant switching will be triggered immediately once faults exceed thresholds, effectively preventing process runaway, parameter drift and false equipment action to guarantee intrinsic safe operation of the control system.
3. Technical Specifications
3.1 Basic Specifications
Model: PM858AK02 Part Number: 3BSE082896R1 Brand: ABB Product Series: AC800M / System 800xA DCS Control System Device Type: Redundant CPU Controller Module Core Functions: System logic operation, I/O bus scheduling, process closed-loop control, redundancy and fault-tolerant management, plant-wide communication interaction, data storage and diagnosis Compatible System: ABB Ability System 800xA Integrated Automation System Matching Accessories: TP830 base unit, TB807 bus terminator, TK850 extension cable, TK851 communication cable, original backup battery Compatible I/O Series: Full range of S800 I/O modules Core Advantages: High computing performance, dual-network redundancy, bumpless switching, explosion-proof & marine certifications, full-dimension diagnosis, outstanding compatibility and expandability
3.2 Core Computing & Storage Specifications
Processor Model: Industrial dedicated MPC866 processor Computing Architecture: High-performance embedded architecture for multi-loop calculation of complex processes Program Storage: Large-capacity non-volatile Flash memory; programs permanently stored without loss Operating Cache: High-speed SRAM cache supporting high-speed cyclic operation of large-scale programs Data Protection: Battery-backed power-fail data backup; long-term retention of fault logs and process parameters Computing Characteristics: Low latency, high synchronization, resistance to computing drift, suitable for dynamic continuous production conditions
3.3 Interface & Communication Specifications
Ethernet Interfaces: Two independent industrial Ethernet ports supporting redundant networking Extension Bus: CEX high-speed system extension bus supporting cascaded expansion of multiple modules Local Bus: Dedicated ModuleBus I/O bus for high-speed scheduling of S800 series I/O Serial Interface: Standard dedicated debugging serial port for program downloading and online debugging Communication Protocols: Compatible with 800xA proprietary protocol, mainstream industrial Ethernet protocols and standard serial protocols Network Modes: Single network, dual redundant network and multi-link fault-tolerant networking supported Transmission Characteristics: High-speed transmission, low packet loss, low latency, precise cross-device synchronization
3.4 Redundancy & Control Performance Specifications
Redundancy Mode: Complete dual CPU hot standby; full-link redundancy covering hardware, bus and communication Switching Characteristics: Automatic bumpless switching upon faults; zero shutdown, zero logic interruption and zero process fluctuation Control Capacity: Supports operation of massive control loops, complex interlock logic and batch process management Debugging Functions: Online configuration, online parameter modification, offline simulation debugging and program verification Diagnostic Functions: Full hardware self-test, bus link monitoring, data verification, fault code recording and time-sequence log storage
3.5 Electrical Power Specifications
Supply Voltage: Standard industrial 24 V DC Operating Voltage Range: 19.2 V～30 V DC wide voltage adaptation Typical Operating Current: 210 mA; Maximum: 360 mA Operating Power Consumption: Typical 5.1 W; Maximum 8.6 W Power Supply Characteristics: Wide voltage compatibility, resistance to power fluctuation, surge protection and instantaneous power failure resistance Power Protection: Built-in overvoltage, overcurrent, short-circuit and instantaneous power-off protection to ensure uninterrupted core computation
3.6 Mechanical & Installation Specifications
Mounting Method: Standard DIN rail mounting and rack slot mounting Matching Base Unit: TP830 dedicated mounting base Fastening Method: Sliding locking structure for convenient assembly and disassembly with stable fixation Structure Form: Compact standardized industrial modular design Housing Material: Industrial flame-retardant, dust-proof, anti-aging high-strength housing Protection Class: IP20 (for closed installation inside standard industrial cabinets) Structural Features: Anti-seismic and anti-vibration, compact structure for long-term continuous operation in cabinets
3.7 Environmental & Certification Specifications
Operating Temperature: 0℃～+60℃ Storage Temperature: -20℃～+85℃ Operating Humidity: 5%～95%RH (non-condensing, free of strong corrosive gases) Explosion-Proof Certification: cULus Class1 Zone2, AEx nA IIC T4 Gc Marine Certifications: Classification society certifications including ABS, BV, DNV-GL, LR, RS and CCS Compliance Standards: UL508 industrial safety, industrial EMC, RoHS environmental standard Environmental Resistance: Humidity-heat resistance, vibration resistance, thermal shock resistance, dust & corrosion resistance, anti-electromagnetic interference Operation Mode: 7×24-hour unattended continuous stable operation all year round
4. Operating Principle
As the core control hub of AC800M DCS system, ABB PM858AK02 controller module realizes computation, scheduling, control and protection of the whole automation system relying on high-performance industrial processor and full-link redundant fault-tolerant architecture. Upon power-on, the module automatically completes full hardware self-test, storage verification, dual Ethernet initialization, activation of CEX bus and ModuleBus bus, system program loading and clock synchronization. It finishes redundant link pairing and standby initialization to guarantee trouble-free startup.
During normal operation, the module collects analog signals, digital signals, equipment status and process point signals from S800 I/O modules via local ModuleBus. With embedded control programs, it rapidly executes core computing tasks including PID closed-loop operation, process logic judgment, equipment interlock verification, timing scheduling and data conversion. Through dual redundant Ethernet, it exchanges process data, equipment operating status and control commands with upper 800xA monitoring system, operator stations and servers. Accurate regulation commands are issued synchronously to drive field actuators and realize stable closed-loop control of key process parameters such as temperature, pressure, flow, liquid level and load, ensuring continuous and stable plant operation.
Under redundant operation mode, master and backup CPUs synchronize program logic, process parameters, operating data and working conditions in real time with fully consistent computing logic and zero deviation of synchronized data. The system continuously monitors hardware status, bus links, communication conditions and program execution. Once hardware failure, communication interruption, computing abnormality or power fluctuation occurs on the primary CPU, bumpless redundant switching is triggered instantly. The standby CPU seamlessly takes over all control tasks without interrupting production processes or affecting equipment operation. Meanwhile, the module automatically records fault codes, time-sequence logs and abnormal information and uploads alarms to upper systems, achieving highly reliable closed-loop control with traceable faults, fault tolerance and continuous operation.
5. Application Scenarios
5.1 Core Main Controller for DCS Systems of Large Process Industries
Widely used in ABB 800xA DCS systems of petroleum, chemical, coal chemical, oil & gas storage and transportation, thermal power, fine chemical, water treatment, metallurgy and other industries. As the core CPU of AC800M control stations, it undertakes control of key process loops, equipment interlock protection, real-time condition monitoring and data storage & interaction. It fits industrial control scenarios featuring massive signal points, complex processes, strict real-time requirements and high stability to ensure continuous stable production of large-scale plants.
5.2 Redundant Uninterrupted Control Systems for High-Risk Conditions
Supported by native dual hot-standby architecture and Zone2 explosion-proof certification, it is designed for high-risk processes, explosion-proof zones and uninterrupted production to build zero-shutdown fault-tolerant control systems. Suitable for core control of reactors, distillation units, compressor packages, boilers, turbines and offshore platform equipment, it completely avoids production shutdown, process accidents and capacity losses caused by single CPU faults and greatly improves system safety and reliability.
5.3 Upgrading and Renovation of Legacy AC800M Systems
As the high-spec K02 variant of PM858 series, it can perfectly replace old low-spec CPU modules to upgrade computing capacity, storage space, communication redundancy and fault tolerance of control stations. Direct in-situ replacement is available without modifying system architecture, control logic and wiring schemes. It addresses common problems of legacy systems such as computing lag, insufficient storage, risks of single-network communication and weak fault tolerance, applicable to technical transformation and intelligent upgrading of old plants.
5.4 Automation Control for Marine and Special Industrial Environments
With multiple marine certifications and outstanding environmental adaptability, it can be deployed for automation control of offshore drilling platforms, marine power systems and offshore storage & transportation facilities. It withstands harsh offshore conditions including high humidity, salt spray, vibration and electromagnetic interference to ensure long-term stable operation of control systems in special scenarios.
5.5 High-Accuracy Process Data Tracing and Compliance Management
Supported by large-capacity local storage and long-term data retention capability, it adapts to management scenarios requiring long-term storage of process trends, production records, fault logs and operation records. It meets requirements of production compliance filing, process optimization, fault diagnosis and quality tracing in chemical, power, pharmaceutical and other industries, ensuring integrity and traceability of production data.
5.6 Key Spare Part for ABB DCS Systems
As a mainstream CPU module of AC800M series, it boasts strong versatility, wide compatibility and high operational stability, serving as an essential spare part for industrial automation maintenance enterprises. It can rapidly respond to emergencies including CPU faults, computing anomalies, communication failure, storage breakdown and failed redundant switching, quickly restore main control capacity of DCS systems and prevent production interruption risks.
