ABB PM858-C 3BSE093350R1 – High-Performance Redundant CPU for Industrial Automation Systems

The ABB PM858-C is a powerful redundant central processing unit designed for demanding applications in the AC 800M controller family. From my experience working with process automation setups in power and water treatment plants, this model stands out when uptime and fault tolerance are non-negotiable. It’s not just about raw speed—it’s how the system handles failure scenarios without dropping control loops.

One thing I appreciate is its seamless integration with existing ABB ecosystems. If you’re upgrading from an older PM8xx series, the transition typically goes smoother than expected—especially if your engineering team uses Control Builder M v6 or later.

Key Features

• Redundant Architecture: Dual CPU configuration ensures continuous operation during failover—typically under 50ms switchover time in most test environments.
• High Memory Capacity: Equipped with 512 MB RAM and 1 GB Flash, allowing complex logic handling and extended data logging without external buffering.
• Integrated Communication Ports: Includes dual Ethernet (10/100 Mbps) and RS-485 for Modbus RTU, which simplifies connectivity to HMIs, SCADA systems, and legacy devices.
• Real-Time Clock with Battery Backup: Maintains accurate timestamps across power cycles—important for audit trails and event diagnostics.
• Firmware Flexibility: Supports online firmware updates without full system shutdown, reducing downtime during maintenance windows.

Technical Specifications

Application Fields

This controller sees heavy use in continuous-process industries. In many cases, we’ve seen it deployed in wastewater treatment facilities where uninterrupted pump sequencing and alarm management are critical. It also fits well in combined heat and power (CHP) stations, oil & gas compressor monitoring, and pharmaceutical batch control. You might notice that plants with high availability targets (like 99.5%+ runtime) tend to favor this module due to its mature redundancy protocol.

Advantages & Value

Procurement teams often look at total cost of ownership, not just sticker price. With the PM858-C, there’s usually less risk involved—ABB has maintained long-term software support for these CPUs, so migration paths remain open for another 8–10 years based on current roadmaps. Spare part availability remains strong globally, which reduces inventory pressure. Also, since many engineers already know Control Builder M, training costs stay low.

Installation & Maintenance

Install in a clean, dry cabinet meeting IP54 standards. Ensure adequate ventilation—don’t stack other heat-generating modules directly beside it. Wiring should follow ABB’s grounding guidelines to avoid noise interference, especially in electrically noisy environments like motor control centers. For maintenance, schedule quarterly visual checks for terminal tightness and fan operation (if applicable). Firmware updates are recommended every 18 months unless patches address specific bugs. Calibration isn’t required for the CPU itself, but connected I/O modules may need periodic checking depending on application severity.

Quality & Certifications

Certified to CE, UL 61010-1, and compliant with RoHS directives. Meets industrial EMC standards including IEC 61000-6-2 and IEC 61000-6-4. ISO 9001 applies to manufacturing processes. The unit comes with a standard 365-day warranty covering defects in materials and workmanship. Repairs or replacements handled through authorized service centers typically take 7–10 business days.

Ordering Notes: Delivery within one week for in-stock units; maximum lead time no more than one month. Payment terms: 50% advance, balance before shipment. Shipped via FedEx, UPS, or DHL based on destination and urgency.