Description

The ABB UNS0867 (order code HIEE405246R0002) is a central processing unit (CPU) module from ABB’s AC 800M family—a scalable, modular programmable logic controller (PLC) platform designed for demanding process automation applications in power generation, oil & gas, chemicals, mining, and water treatment. As the “brain” of the AC 800M controller rack, the UNS0867 executes control logic written in IEC 61131-3 languages (e.g., Structured Text, Function Block Diagram), manages I/O data exchange, and coordinates communication with engineering stations, HMIs, and enterprise systems.

This specific variant (UNS0867) is a high-performance, non-redundant CPU optimized for medium to large control tasks. It features an integrated Profibus DP master interface, enabling direct connection to remote I/O stations (e.g., S800 I/O via TB820/TB840 baseplates) without requiring a separate communication module. The UNS0867 supports up to 1 MB of application memory, fast scan cycles (<10 ms typical), and robust diagnostics—making it suitable for both basic regulatory control and complex batch or sequence logic.

When deployed within ABB’s System 800xA distributed control architecture, the UNS0867 becomes part of a unified operations environment that merges process control, electrical control, safety, and asset optimization on a single engineering and operator platform.

Technical Specifications

Main Features and Advantages

Tight integration with System 800xA:
The ABB UNS0867 is natively managed by ABB’s System 800xA, allowing unified engineering, alarm management, historical trending, and operator graphics. Changes made in Control Builder M are automatically synchronized across the system—reducing configuration errors and commissioning time.

High I/O density and scalability:
A single UNS0867 can manage dozens of remote I/O stations over Profibus, supporting analog, digital, and specialty modules (e.g., HART, pulse counting). This makes it ideal for geographically dispersed plants like water networks or pipeline terminals.

Robust diagnostics and serviceability:
Built-in LEDs indicate RUN, STOP, I/O COMM FAULT, and battery status. The service port enables local upload/download and troubleshooting without network access. Battery-backed RAM preserves program and last-known-good values during power loss.

Long lifecycle and backward compatibility:
As part of the mature AC 800M platform (introduced in early 2000s), the UNS0867 benefits from extensive field validation and long-term ABB support. It remains compatible with newer I/O and communication modules, protecting legacy investments.

Application Field

The ABB UNS0867 is commonly found in:

• Power Plants: Controlling boiler auxiliaries, condensate systems, and flue gas desulfurization (FGD).

• Water & Wastewater: Managing pump stations, clarifiers, and chemical dosing with remote I/O over Profibus.

• Mining & Minerals: Automating conveyor belts, crushers, and slurry pipelines in harsh environments.

• Chemical Batch Processes: Executing recipe sequences with precise timing and interlocks.

• District Heating Networks: Coordinating pressure, temperature, and flow across multiple substations.

While not certified for standalone SIL 3 safety functions, the UNS0867 can coexist in hybrid architectures alongside AC 800M HI (High Integrity) controllers for safety-critical layers.

Related Products

• PM864A / PM865A: Redundant CPU alternatives for high-availability applications.

• CI854A: Ethernet communication module – adds Modbus TCP, OPC UA server, and 800xA connectivity.

• TB820 / TB840: Baseplates for S800 I/O modules connected via Profibus.

• Control Builder M: Official programming and configuration tool.

• TK811V015: AC 800M rail chassis – required to mountUNS0867 and I/O modules.

Installation and Maintenance

Installation best practices:
Mount the UNS0867 in a ventilated cabinet with adequate spacing for heat dissipation. Ensure Profibus cables use proper termination (120 Ω) and shielding grounded at one end. Use a fresh BT810 backup battery during initial commissioning.

Maintenance guidance:
Replace the backup battery every 3–5 years to prevent memory loss. Monitor CPU load via Control Builder M—keep below 70% for headroom during transients. If communication errors occur, check Profibus baud rate consistency and segment length limits.