ABB PM861AK01 3BSE018157R1 | AC800M Redundant CPU Processor for 800xA DCS

Description

Product Core Brief

• Model: PM861AK01
• Order Code: 3BSE018157R1
• Brand: ABB
• Series: AC800M / Industrial IT 800xA
• Core Function: Redundant processor unit (CPU) for ABB AC800M distributed control systems
• Product Type: DCS CPU Module / Redundant Controller
• Key Specs: 32-bit RISC CPU, 48 MHz | 16 MB RAM with ECC | CPU / power / network redundancy | Control Builder M engineering | PROFIBUS DP, Modbus, Foundation Fieldbus communication
• Condition: New Original / New Surplus (verify per listing)

Key Technical Specifications

Note: PM861AK01 is the “A” version of PM861, supporting redundant communication modules such as CI85A, CI860 and BC810. It is not interchangeable with non-redundant PM861K01 (3BSE018105R1) without verifying system configuration.

Product Introduction

The ABB PM861AK01 (3BSE018157R1) is a redundant processor unit for the ABB AC800M controller platform, widely used in Industrial IT 800xA distributed control systems. It serves as the central processing unit for AC800M stations, executing control logic, managing fieldbus communication, and coordinating local and remote I/O for continuous and batch process applications.

The module is built around a 32-bit MPC860 RISC processor running at 48 MHz, with 16 MB of RAM featuring error detection and correction (ECC). It supports full hardware redundancy — including CPU, power supply, and control network — with automatic switchover in less than 10 ms, making it suitable for critical applications in power generation, oil and gas, chemical processing, and water treatment.

The PM861AK01 baseplate includes two Ethernet ports (CN1, CN2) for control network communication and two RS-232C serial ports (COM3, COM4). COM3 supports modem control signals, while COM4 is isolated for configuration tools. Through the CEX bus, it can accommodate up to 12 communication modules for PROFIBUS DP, Modbus, Foundation Fieldbus, and other protocols. The ModuleBus supports up to 96 I/O modules in single-CPU mode or 84 modules in redundant mode.

For MRO buyers and system integrators maintaining legacy AC800M / 800xA installations, PM861AK01 is typically replaced during controller upgrades, panel rebuilds, spare-part replenishment, or when an existing station experiences CPU faults, communication loss, or redundancy errors. Because the “A” suffix indicates support for redundant communication modules, it must be matched carefully against the existing system configuration. The order code 3BSE018157R1 should be confirmed exactly before replacement.

QA & Testing SOP

1. Nameplate verification — Confirm PM861AK01 and full order code 3BSE018157R1.
2. Visual inspection — Check the module housing, TP830 baseplate connectors, Ethernet/serial ports, and status LEDs.
3. Battery check — Verify the 3.6 V lithium backup battery is installed and within voltage range.
4. Power-on test — Install into a compatible AC800M rack with the correct power module and verify normal LED status.
5. Communication check — Confirm communication with the Control Builder M engineering station via Ethernet.
6. Redundancy verification — If configured for redundancy, verify RCU link synchronization and switchover behavior.
7. Application verification — Verify existing program download, online monitoring, and fault-free operation.

All units ship in anti-static packaging. A test log can be provided on request when rack testing is available.

Installation Pitfalls & Guide

Confirm it is AC800M, not AC800F or Advant OCS. PM861AK01 belongs to the AC800M / 800xA platform. It is not interchangeable with AC800F PM802F, Advant OCS PM665/PM825, or AC500 PLCs.

Verify the “A” suffix. PM861AK01 (3BSE018157R1) is the redundant-capable “A” version. The non-redundant PM861K01 (3BSE018105R1) has different capabilities. Do not substitute without verifying the system configuration.

Check K01 vs K02 variants. PM861AK01 and PM861AK02 are both AC800M processor units, but firmware, hardware revision, or redundancy features may differ. Always confirm the exact order code.

Verify power and baseplate compatibility. PM861AK01 mounts on a TP830 baseplate and pairs with SD821/SD822/SD823 power modules.

Back up before replacement. Save the existing control application, configuration, and parameter set via Control Builder M before removing the faulty module.

Handle as ESD-sensitive equipment. Use anti-static packaging and avoid touching connectors or PCB components.

Replacement steps:

1. Back up the control application and record current alarms.
2. Power down the rack if required by site procedure.
3. Remove the faulty PM861AK01 and label all connections.
4. Install the replacement module and verify seating on the TP830 baseplate.
5. Power up and check status LEDs.
6. Verify communication via Control Builder M, load the application, and confirm stable operation.
7. If redundant, verify RCU synchronization and perform a controlled switchover test.

Technical FAQ

What is the order code for PM861AK01? The factory order code is 3BSE018157R1.

How is PM861AK01 different from PM861K01? PM861AK01 is the “A” version, supporting redundant communication modules (CI85A, CI860, BC810). PM861K01 (3BSE018105R1) is the non-redundant version.

Does it support CPU redundancy? Yes. PM861AK01 supports CPU redundancy with automatic switchover in less than 10 ms.

Which software is used for programming? ABB Control Builder M (CBM), supporting IEC 61131-3 languages including FBD, LD, IL, ST, and SFC.

What communication protocols does it support? It supports PROFIBUS DP, Modbus, Foundation Fieldbus, and other protocols via CEX bus communication modules.

Is this product still in production? AC800M is a mature platform. Availability is typically through surplus, refurbished, or remaining OEM stock. Confirm condition and warranty before purchase.

Do you stock single units? Yes. Single units are available for MRO replacement; multi-unit spares and project support can be quoted on request.