PM856AK01 ABB AC800M CPU with CompactFlash Interface

Product Overview

The ABB PM856AK01 (Part Number: 3BSE066490R1) functions as the primary processing core for the AC800M distributed control system. This brand-new, original CPU unit integrates a high-performance microprocessor with 8MB of RAM and a dedicated real-time clock to manage complex automation logic. It serves as the central intelligence hub, coordinating data between the Control Network and I/O subsystems. Designed for high-availability environments, the PM856AK01 supports redundant Ethernet communications and provides a modular CompactFlash interface for persistent data storage and firmware management.

Technical Specifications

The PM856AK01 utilizes a high-density base plate architecture to maintain the following technical parameters:

Engineering Advantages

The ABB PM856AK01 solves the challenge of network reliability and hardware identification in large-scale DCS deployments. Every TP830 base plate carries a unique factory-assigned Ethernet address, which grants each CPU a distinct hardware identity. This eliminates IP conflict risks during system initialization and simplifies asset tracking across the plant network.

For installation efficiency, the unit employs a unique slide & lock mechanism. This allows technicians to attach or detach the controller from a DIN rail without tools, significantly reducing commissioning time in cramped control cabinets. The communication architecture incorporates dual RJ45 Ethernet ports (CN1 and CN2) to provide physical redundancy; if one network segment fails, the controller maintains seamless communication via the secondary path. Additionally, the inclusion of an isolated serial port (COM4) protects the CPU during configuration. By isolating the tool connection from the internal system logic, the PM856AK01 prevents electrical surges from the PC or handheld device from damaging the primary processor, ensuring long-term operational uptime in harsh industrial environments.

FAQs

How do I perform a cold start on the PM856AK01?

You utilize the INIT push button located on the front of the CPU board. Simultaneously pressing this button while inserting the CompactFlash card containing the system image allows the controller to reload its firmware and application logic from a known-good state.

What is the purpose of the two different serial ports (COM3 and COM4)?

COM3 serves as a standard RS-232C port with modem control signals, typically used for connecting external peripheral devices or serial MODBUS communication. COM4 is specifically isolated for the connection of a configuration tool (Control Builder), providing an extra layer of electrical protection for the CPU during programming.

Does the PM856AK01 support memory expansion?

The unit features 8MB of built-in RAM for logic execution. For persistent storage, you can utilize the CompactFlash interface to store the application code, ensuring the controller retains its logic even after a total power failure or long-term storage.

Can I replace a PM856A with a PM856AK01?

Yes. The PM856AK01 is the modern version of the PM856A series. It maintains full backwards compatibility with existing AC800M base plates and software configurations, provided your 800xA or Control Builder version supports the hardware revision. Always verify the firmware compatibility before swapping units in a live process.