Overview of the ABB PM860A Processor Unit

The ABB PM860A (Article Number: 3BSE066495R1, often sold as kit PM860AK01) is a robust and highly efficient processing unit designed for the AC 800M controller family. As a central component of the ABB Ability™ System 800xA, this processor provides the computational power necessary for complex industrial automation tasks. ABB engineered the PM860A to deliver high availability, modularity, and seamless integration across various communication protocols, including Ethernet, PROFIBUS DP, and Foundation Fieldbus.

This controller features a MPC860 microprocessor operating at 48 MHz. It strikes an excellent balance between processing speed and power consumption, making it a staple in refineries, power plants, and manufacturing facilities worldwide.

Hardware Architecture and Performance

The PM860A hardware consists of a CPU board and a base plate (typically the TP830). The CPU board houses the microprocessor, 16 MB of RAM, a real-time clock, and a CompactFlash interface for firmware storage and data backup.

• Processing Speed: The unit executes 1,000 boolean operations in just 0.23 ms. This rapid processing ensures that the controller handles high-speed logic and complex control loops without latency.
• Memory Capacity: With 16 MB of onboard RAM (and approximately 10.3 MB available for user applications), the PM860A supports up to 32 separate applications and 64 programs per application.
• Task Management: The controller manages up to 32 tasks simultaneously, with cycle times as low as 1 ms. This makes it ideal for time-critical applications where precision is mandatory.

Advanced Connectivity and Communication

Connectivity remains a core strength of the PM860A. The base plate provides multiple ports to ensure the controller stays integrated with both the control network and field devices.

1. Ethernet Ports (CN1, CN2): Two RJ45 Ethernet ports facilitate connection to the Control Network. These ports support the MMS (Manufacturing Message Service) and IAC (Inter Application Communication) protocols. Each base plate carries a unique hardware identity via its factory-assigned Ethernet address.
2. Serial Ports (COM3, COM4): The unit includes two serial interfaces. COM3 is a standard RS-232C port equipped with modem control signals. COM4 is an isolated port specifically dedicated to connection with configuration tools and service diagnostics.
3. Expansion Capabilities: The PM860A supports the CEX-bus for connecting up to 12 communication interface modules. Additionally, it manages I/O clusters via the Modulebus, supporting up to 96 I/O modules through a combination of electrical and optical links.

Reliability in Harsh Environments

ABB designed the PM860A to withstand the rigors of industrial settings. The unit features G3-compliant corrosion protection according to ISA 71.04 standards. This coating protects the internal circuitry against moisture and corrosive gases, significantly extending the product’s lifespan in chemical or offshore environments.

• Operating Temperature: The unit functions reliably between 0°C and +55°C.
• Marine Certifications: The PM860A holds prestigious certifications from ABS, BV, DNV-GL, and LR, making it suitable for maritime and offshore applications.
• Hazardous Locations: It is certified for use in Class 1, Zone 2 environments (AEx nA IIC T4), ensuring safety in potentially explosive atmospheres.

Installation and Maintenance

The PM860A utilizes a unique “slide & lock” mechanism for DIN rail attachment. This design allows maintenance teams to install or detach the unit quickly without specialized tools. The front panel features a clear set of LED indicators for status, errors, and network activity, which simplifies fault diagnosis. A built-in lithium backup battery (3.6 V) ensures that the real-time clock and critical memory data remain intact during power interruptions.

The controller integrates fully with the 800xA Control Builder software. This software environment allows engineers to configure, program, and monitor the PM860A using standard IEC 61131-3 programming languages.

Why Choose the PM860A?

Investing in the ABB PM860A ensures long-term stability for your automation infrastructure. Its modular design allows for step-by-step expansion as your plant’s needs grow. By utilizing standard communication hardware like switched Ethernet, the PM860A reduces the total cost of ownership while providing the high-integrity performance that ABB customers expect. Whether you are managing a single I/O cluster or a complex multi-node network, the PM860A delivers the reliability required to keep your operations running 24/7.