The PM851AK01 is a high-performance controller hardware combination within the ABB Ability™ System 800xA® series, consisting of the PM851A Processor Unit and the TP830 Baseplate. This product is designed for industrial automation and control applications, featuring high reliability, a modular architecture, and powerful communication capabilities. It is suitable for various fields including process control, manufacturing automation, and energy management.
As a key component of the 800xA system, the PM851AK01 provides complete control and data processing capabilities, supports multiple industrial communication protocols, and offers good environmental adaptability and electromagnetic compatibility, making it suitable for demanding industrial environments. The controller can be configured and programmed via the 800xA Control Builder, offering users a flexible and scalable control solution.
2. Product Composition and Hardware Architecture
2.1 PM851A Processor Unit
The PM851A is the core processing module of the controller, based on an MPC860 microprocessor running at 48 MHz. It incorporates 12 MB of SDRAM, supports internal or external battery backup to ensure data retention during power loss, and integrates a real-time clock, LED status indicators, an INIT button, and a CompactFlash interface for firmware updates and data storage.
2.2 TP830 Baseplate
The TP830 provides the mechanical mounting and electrical connection foundation for the processor. It supports DIN rail mounting via a unique slide-and-lock mechanism, allowing for easy installation and removal. The baseplate integrates the following communication ports:
CN1: Ethernet port (10Base-T, RJ45)
CN2: Reserved Ethernet port (CN1 only is supported for PM851A)
COM3: Serial port (RS-232C, with modem support)
COM4: Serial port (RS-232C, for service tools)
Each TP830 baseplate is labeled with a unique Ethernet MAC address, providing a hardware identity for the controller.
2.3 Memory and Storage
The PM851A is equipped with:
2 MB Flash PROM: For firmware storage
12 MB SDRAM: For application execution
CompactFlash interface: Supports application loading and cold retain data storage
3. Communication and Interface Details
| Interface Type | Communication Speed | Signal Standard | Connector | Remarks |
| CN1 Ethernet | 10 Mbit/s (half duplex) | IEEE 802.3, 10Base-T | RJ45 | PM851A supports CN1 only; redundant Ethernet not available |
| COM3 Serial Port | 75 – 19200 baud (selectable) | RS-232C | RJ45 | Supports modem control signals |
| COM4 Serial Port | 9600 baud (fixed) | RS-232C | RJ45 | For service/configuration tools, isolated design |
| Electrical ModuleBus | — | Dedicated bus protocol | Terminal block | Supports 1 S800 I/O cluster, up to 12 I/O units |
| Optical ModuleBus | — | Fiber optic communication | Fiber optic interface | PM851A supports max. 1 S800 I/O cluster |
| CEX-Bus | — | Extended communication bus | Dedicated interface | Supports max. 1 communication interface unit |
4. Power and Electrical Characteristics
| Parameter | Value |
| Nominal Input Voltage | 24 V DC |
| Input Voltage Range | 19.2 – 30 V DC |
| Typical Current Consumption | 180 mA (max. 300 mA) |
| Typical Power Dissipation | 5 W (max. 10 W, including bus supply) |
| Power Connector | 4-pin screw terminal (L+, L-, SA, SB) |
| Redundant Power Status Inputs | SA, SB (high level ≥15 V, low level ≤8 V) |
| Internal Power Reservoir | 5 ms (supports controlled power down) |
| Rated Isolation Voltage | 50 V |
| Dielectric Test Voltage | 500 V AC |
5. Environmental and Certification Information
| Item | Description |
| Operating Temperature | 0 to +55 °C |
| Storage Temperature | -40 to +70 °C |
| Rate of Temperature Change | 3 °C/minute (compliant with IEC/EN 61131-2) |
| Pollution Degree | Degree 2 (IEC/EN 61131-2) |
| Corrosion Protection | Compliant with ISA 71.04 G3 |
| Relative Humidity | 5 – 95%, non-condensing |
| Vibration Resistance | 10 – 150 Hz, 0.0375 mm amplitude, 0.5 g acceleration |
| Protection Rating | IP20 |
| Altitude | ≤2000 m |
| Electromagnetic Compatibility | Compliant with EN 61000-6-4 (Emission) & EN 61000-6-2 (Immunity) |
| Electrical Safety Certifications | EN 50178, IEC 61131-2, UL 61010-1, UL 61010-2-201 |
| Hazardous Location Certification | cULus Class 1, Zone 2, AEx nA IIC T4 |
| Marine Certifications | ABS, BV, DNV-GL, LR |
| Environmental Compliance | EU RoHS, UAE RoHS, China RoHS |
| Waste Compliance | Compliant with DIRECTIVE/2012/19/EU (WEEE) |
| CE Mark | Yes |
6. Features and Functions Detailed
6.1 High-Reliability Design
The PM851AK01 utilizes industrial-grade components and stringent manufacturing processes, providing good noise immunity and long-term operational stability. Its internal power reservoir circuit provides at least 5 ms of hold-up time during power interruptions, ensuring the CPU can perform a controlled shutdown to prevent data corruption.
6.2 Flexible Storage and Backup
The controller supports application loading and data storage via CompactFlash cards, facilitating system upgrades and maintenance. Memory data can be backed up by an internal lithium battery (minimum backup 2 weeks) or an external battery unit SB821 (minimum backup 8 months), ensuring critical data is retained during power outages.
6.3 Modular Expansion Capability
Up to 12 S800 I/O units can be connected via the Electrical ModuleBus, supporting flexible I/O configuration. Furthermore, the CEX-Bus and Optical ModuleBus provide additional communication and expansion capabilities for the system, suitable for distributed control systems.
6.4 Easy Installation and Maintenance
DIN rail mounting with a slide-and-lock mechanism allows for quick, tool-free installation or removal. The front panel features LED indicators and an INIT button for easy status monitoring and fault diagnosis. All communication ports use RJ45 connectors for simple cabling.
6.5 Powerful Communication Integration
Supports industrial Ethernet (10Base-T) and serial communication (RS-232C), enabling seamless integration into existing control networks. The COM3 port supports modem connection for remote maintenance and data transfer.
7. Performance Notes
The performance of the PM851A in executing application programs is comparable to the PM856A but lower than the PM860A. Specifically:
This performance difference stems mainly from variations in processor architecture and memory configuration, making it suitable for applications with moderate real-time requirements and a focus on cost-effectiveness.
8. Application Areas
The PM851AK01 is suitable for the following industrial scenarios:
Process Automation (Chemical, Oil & Gas)
Manufacturing Execution Systems (MES)
Energy Management and Distribution Systems
Water Treatment and Environmental Control
Marine Control Systems
Building Automation
