Description
1. Product Overview
ABB PM864A (Part No.: 3BSE018162R1) is a mid-range high-performance industrial CPU controller module of the AC800M series manufactured by ABB, Switzerland. It is fully compatible with ABB Ability™ System 800xA integrated DCS distributed control system and serves as the core computing and scheduling unit for automation control stations in process industries. As an upgraded iteration of PM864, the module adopts a 100 MHz high-performance industrial MPC860 processor, equipped with large-capacity flash memory and operating RAM. It integrates dual-Ethernet communication, multiple serial interfaces, high-speed CEX extension bus and ModuleBus local I/O bus, delivering capabilities of high-speed deterministic operation, full-link communication scheduling, complex process control and global fault diagnosis.
PM864A supports two operation modes: standalone single-CPU operation and dual-CPU hot-standby redundancy, enabling automatic bumpless switching upon faults for medium and medium-complex process industrial control applications. The module is natively compatible with the full range of S800 I/O modules. It supports expansion of up to 12 single-channel CEX bus modules or 6 sets of redundant CEX bus modules, allowing flexible construction of standardized, modular distributed control systems. Certified with UL, CE, DNV and other industrial and marine approvals, it features outstanding anti-interference, anti-vibration and moisture resistance. Widely deployed in power generation, water treatment, fine chemical, oil & gas storage and transportation, metallurgy, light industry automation and other sectors, it applies to turnkey delivery of new DCS systems, capacity expansion and upgrade of legacy AC800M control stations, redundant system retrofitting and replacement of faulty spare parts. It is a mainstream core CPU module within the ABB AC800M industrial control ecosystem.
2. Technical Features
2.1 High-Performance Industrial Processor for Deterministic Real-Time Control
Equipped with an industrial MPC860 processor running at 100 MHz, it adopts a 32-bit embedded high-speed computing architecture with excellent logic operation, floating-point calculation and batch data processing performance. It supports a minimum deterministic program scan cycle of 1 ms, reliably handling medium and medium-high density computing tasks including multi-loop PID closed-loop regulation, complex equipment interlocks, precise timing scheduling and batch process control. The operation mechanism is optimized for continuous variable-load and dynamic process switching conditions in process industries to eliminate calculation delay, logic stall and timing deviation. It ensures millisecond-level response and process control accuracy of the control system, meeting stringent real-time control requirements for medium-scale process industries.
2.2 Large-Capacity Storage for Stable Execution of Complex Process Programs
It adopts an industrial partitioned storage architecture with 8 MB Flash for permanent program storage and 32 MB high-speed RAM for operating cache. It can fully store large-scale user control programs, process recipes, interlock logic, system configuration parameters and device configuration information. Supported by original battery-backed power-fail protection, operating logs, time-sequence fault data and process trend parameters can be retained long after power loss. It prevents parameter loss, program failure and system reset after shutdown. No external storage device is required to satisfy process storage and data tracing demands of medium-scale plants, suitable for long-term continuous production.
2.3 Integrated Dual Ethernet & Multi-Serial Ports for Flexible Networking and Strong Compatibility
Two independent industrial Ethernet ports are integrated to support redundant fault-tolerant networking with mutually hot-backed links. Failure of a single network link will not affect overall system communication and process operation, effectively avoiding risks of process runaway and data interruption caused by network outage. Two RS-232C serial communication interfaces are provided for equipment commissioning, program downloading and point-to-point communication with third-party devices respectively. Combined with high-speed CEX system extension bus and dedicated ModuleBus I/O bus, millisecond-level acquisition of I/O signals and synchronous issuance of control commands are realized, ensuring precise coordination between distributed I/O nodes and the main controller, adaptable to plant-wide centralized management and distributed automatic control architectures.
2.4 Native Redundant Hot-Standby for Uninterrupted Production
The module natively supports the standard AC800M dual-CPU hot-standby redundant architecture. Master and backup CPUs run in parallel and synchronously, mirroring program logic, process parameters, operating conditions and cached data in real time with fully consistent computation logic and zero synchronization deviation. The system fault switching time is ≤10 ms. When the primary CPU encounters hardware failure, communication interruption, computing abnormality, power fluctuation or other issues, automatic bumpless, non-stop switching without process fluctuation is achieved. The standby CPU seamlessly takes over all control tasks without interrupting production processes or altering equipment operating status, greatly improving system availability for 7×24-hour continuous production.
2.5 Standardized Configuration Programming with Excellent Expandability
Fully compatible with ABB 800xA Control Builder official configuration software, it complies with IEC 61131-3 international industrial control standards. It supports mainstream programming languages including Ladder Diagram, Function Block Diagram, Structured Text and Sequential Function Chart, enabling customization of process control logic, PID loops, safety interlock strategies and equipment management schemes. Natively compatible with all AC800M controller hardware, full series of S800 I/O modules and the 800xA system architecture, it seamlessly connects new and legacy systems and supports online program modification, parameter download, logic debugging and signal point expansion. Analog, digital, communication expansion and safety interlock units can be flexibly added to accommodate various process technical transformation and system upgrading projects.
2.6 Full-Dimension Self-Diagnosis and Fault Tolerance for High System Safety
Embedded with comprehensive self-diagnosis 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/ModuleBus 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 computation is available for minor abnormal conditions; once faults exceed thresholds, system audible & visual alarms, fault recording and redundant switching are triggered immediately, effectively preventing process runaway, parameter drift and false equipment action to guarantee intrinsically safe and stable operation of the control system.
3. Technical Specifications
3.1 Basic Specifications
Model: PM864A Part Number: 3BSE018162R1 Brand: ABB Product Series: AC800M / System 800xA DCS Control System Device Type: High-Performance 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 fault diagnosis Compatible System: ABB Ability System 800xA Integrated Automation System Matching Accessories: TP830 mounting base unit, TB807 bus terminator, original backup battery, dedicated communication extension cables Compatible I/O Series: Full range of S800 I/O modules Maximum Expansion Capacity: Supports up to 12 single-channel CEX bus modules or 6 sets of redundant CEX bus modules Core Advantages: High deterministic computation, dual-network redundancy, millisecond-level switching, large-capacity storage, full-dimension diagnosis, superior compatibility and expandability
3.2 Core Computing & Storage Specifications
Processor Model: Industrial MPC860 Processor Processor Frequency: 100 MHz Computing Architecture: 32-bit embedded high-speed operation architecture Minimum Scan Cycle: 1 ms (deterministic real-time control) Non-Volatile Program Storage: 8 MB Flash High-Speed Operating Cache: 32 MB RAM Data Protection: Original battery-backed power-fail data backup Data Retention: Long-term storage of programs, parameters, fault logs and process trend data after power loss Computing Characteristics: Low latency, high synchronization, resistance to computing drift, suitable for continuous dynamic production conditions
3.3 Interface & Communication Specifications
Ethernet Interfaces: Two independent industrial Ethernet ports supporting redundant fault-tolerant networking Serial Interfaces: 2 × RS-232C interfaces (for equipment commissioning, program downloading and third-party communication respectively) System Extension Bus: High-speed CEX bus supporting cascaded expansion of multiple modules Local I/O Bus: Dedicated ModuleBus for high-speed scheduling of S800 series I/O modules Communication Protocols: Compatible with 800xA proprietary protocol, MMS, IAC, mainstream industrial Ethernet protocols and general serial protocols Network Modes: Single network, dual redundant network and multi-link fault-tolerant networking supported Switching Response Speed: Redundancy switching time ≤10 ms Transmission Characteristics: High-speed transmission, low packet loss, low latency, precise cross-device synchronization
3.4 Redundancy & Control Performance Specifications
Redundancy Mode: Standalone single-CPU operation, dual-CPU hot-standby redundant operation Switching Characteristics: Automatic bumpless switching upon faults; zero shutdown, zero logic interruption and zero process fluctuation Control Capacity: Supports multi-loop PID operation, complex equipment interlocks, batch process management and precise timing scheduling Debugging Functions: Online configuration, online parameter modification, offline simulation debugging, program verification and backup Diagnostic Functions: Full hardware self-test, bus link monitoring, data verification, fault code recording and time-sequence log storage
3.5 Electrical Power Specifications
Rated Supply Voltage: 24 V DC industrial DC power supply Wide Operating Voltage Range: 18 V～32 V DC Typical Operating Power Consumption: 22 W Power Supply Characteristics: Wide voltage adaptation, 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 and data integrity
3.6 Mechanical & Installation Specifications
Mounting Method: Standard DIN rail mounting and rack slot mounting for AC800M system Matching Base Unit: TP830 dedicated mounting base Fastening Method: Sliding locking structure for convenient assembly and disassembly with stable and anti-loose fixation Structure Form: Compact standardized industrial modular design Housing Material: Industrial flame-retardant, dust-proof, anti-aging high-strength engineering housing Protection Class: IP20 (for closed installation inside standard industrial cabinets) Structural Features: Compact structure, anti-seismic and anti-vibration, low temperature rise, suitable for long-term continuous operation in cabinets
3.7 Environmental Specifications
Operating Temperature: 0℃～+60℃ Storage Temperature: -20℃～+85℃ Operating Humidity: 5%～95%RH (non-condensing, free of strong corrosive gases) Anti-Corrosion Grade: Industrial G3 anti-corrosion protection Environmental Resistance: Humidity-heat resistance, vibration resistance, thermal shock resistance, dust & corrosion resistance, anti-electromagnetic interference Operation Mode: 7×24-hour unattended uninterrupted stable operation all year round
4. Operating Principle
As the core computing hub of AC800M DCS system, ABB PM864A CPU module realizes logic operation, bus scheduling, process control and safety protection of the whole automation system relying on the 100 MHz high-speed processor, deterministic real-time computing architecture, dual-network redundancy and full-link fault-tolerant mechanism. Upon power-on, the module automatically completes full-dimension hardware self-test, storage verification, dual Ethernet port initialization, activation of CEX extension bus and ModuleBus local bus, system program loading and clock synchronization. Under redundant configuration, pairing of master-backup CPU links and data synchronization are automatically finished to complete standby initialization and ensure trouble-free startup.
During normal operation, the module collects analog signals, digital signals, equipment status and process point signals from S800 series I/O modules via ModuleBus. Based on embedded control programs, it executes core computing tasks including PID closed-loop operation, process logic judgment, equipment interlock verification, timing scheduling and data conversion at a minimum scan cycle of 1 ms. Through dual redundant Ethernet, process data, equipment operating status and control commands are exchanged with upper 800xA monitoring system, operator stations, servers and third-party intelligent devices. Accurate regulating commands are synchronously issued 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 cache and working conditions in real time with fully consistent computing logic and millisecond-level zero-deviation data synchronization. The system continuously monitors hardware status, bus links, communication conditions and program execution. Once the primary CPU suffers hardware failure, communication interruption, computing abnormality, power fluctuation or other faults, bumpless redundant switching is triggered within 10 ms. The standby CPU seamlessly takes over all control, communication and scheduling tasks without interrupting production processes or changing equipment operating parameters. Meanwhile, the module automatically records fault codes, time-sequence logs and abnormal information, uploads alarms to upper systems, and achieves highly reliable closed-loop control featuring traceable faults, fault tolerance and continuous operation.
5. Application Scenarios
5.1 Core Main Controller for Medium-Scale Process Industry DCS Systems
Widely used in ABB 800xA DCS systems for medium-scale process industries including fine chemical, water treatment, oil & gas storage and transportation, thermal power, metallurgy and light industry. As the core CPU of AC800M control stations, it undertakes control of key process loops, equipment interlock protection, real-time condition monitoring, data storage and plant-wide data exchange. It fits industrial control scenarios with medium-to-large signal points, moderately complex processes, strict real-time requirements and high stability to guarantee continuous stable plant production.
5.2 Construction of High-Reliability Redundant Uninterrupted Control Systems
Supported by native dual-CPU hot-standby architecture and 10 ms ultra-fast bumpless switching capability, it is designed for continuous production scenarios requiring zero shutdown to build high-fault-tolerant and high-availability distributed control systems. Suitable for key equipment control of medium & small reaction units, integrated water treatment equipment, waste heat power generation systems and conveying units, it thoroughly avoids production shutdown, process fluctuation and capacity loss caused by single CPU faults and significantly improves system safety and stability.
5.3 Upgrade, Renovation and Capacity Expansion of Legacy AC800M Systems
As an upgraded version of PM864, it can perfectly replace old low-spec CPU modules in-situ to realize low-cost upgrades of control station computing capacity, storage space, dual-network redundancy and real-time control precision. No modification of system architecture, control logic and wiring scheme is required. It addresses common problems of legacy systems such as computing lag, insufficient program capacity, single-network communication risks and weak fault tolerance, applicable to technical transformation, signal point expansion and intelligent upgrading of old plants.
5.4 Automation Control for Marine and Harsh Environments
With DNV marine certification, G3 anti-corrosion performance and outstanding environmental adaptability, it can be deployed for automation control of marine power systems, offshore auxiliary storage & transportation equipment and coastal industrial control devices. It withstands harsh conditions including high humidity, salt spray, vibration and strong electromagnetic interference to ensure long-term uninterrupted stable operation of control systems in special scenarios.
5.5 Process Data Tracing and Production Compliance Management
Supported by 8 MB + 32 MB large-capacity storage and long-term power-fail data retention capability, it can completely store process trend curves, production records, equipment fault logs and operation traceability records. It meets demands of production compliance filing, process optimization, fault tracing and quality control in water treatment, power, fine chemical and other industries, ensuring integrity and traceability of production data.
5.6 Core Spare Part for ABB AC800M Systems
As a mainstream CPU module of the AC800M series, it features strong versatility, wide compatibility and high operational stability with low failure rate, serving as an essential spare part for industrial automation maintenance. It can rapidly respond to on-site emergencies such as CPU computing abnormality, communication failure, storage breakdown and failed redundant switching, quickly restore main control capacity of DCS systems and mitigate risks of production interruption.
