ABB PM820 – High-Performance Redundant Automation Controller for Critical Process Applications

The ABB PM820 isn’t just another PLC—it’s a modular, fault-tolerant automation controller built for environments where downtime isn’t an option. Think refinery safety interlocks, power plant boiler control, or continuous pharmaceutical batch systems. From my experience supporting mid-to-large-scale process projects, the PM820 stands out when you need deterministic execution, hot-swappable redundancy, and native integration with ABB’s 800xA DCS ecosystem—without forcing you into proprietary lock-in.

One thing I appreciate is how cleanly it bridges legacy fieldbus infrastructure (like Profibus DP or Modbus RTU) with modern Ethernet-based control layers. You might notice that unlike many entry-level controllers, the PM820 doesn’t require external gateways to talk to HART-enabled transmitters or Foundation Fieldbus segments—it handles those natively through optional interface modules.

Key Features

• Hot-standby redundancy — Dual CPU modules synchronize state in real time; failover typically occurs in under 50 ms, with no loss of I/O or active alarms.
• Modular I/O architecture — Supports up to 16 I/O modules per rack (including analog input/output, digital I/O, and specialty modules like thermocouple or pulse counting), all with channel-level diagnostics.
• Integrated safety logic — Certified to SIL 2 per IEC 61508 (TÜV-certified firmware), enabling safety shutdown functions without requiring a separate safety PLC in many cases.
• Native 800xA integration — Uses standard ABB AC 800M engineering tools (Control Builder M) and communicates over ABB’s proprietary AC 800M protocol as well as OPC UA and Modbus TCP.
• Extended environmental tolerance — Rated for operation from −25°C to +70°C, and tested for vibration resistance up to 5 g (10–500 Hz), making it suitable for offshore or mobile plant installations.

Technical Specifications

Application Fields

The PM820 shows up most often where uptime, traceability, and regulatory compliance converge. In water treatment plants, it’s used for SCADA-integrated pump station control with built-in audit logging. In chemical manufacturing, customers rely on its deterministic scan cycle (as low as 5 ms) for reactor temperature ramping sequences. One client in Norway even deployed it on a floating LNG facility—where cabinet space is tight and vibration is constant—and reported zero unplanned reboots over 18 months. It’s less common in discrete assembly lines (where Allen-Bradley or Siemens S7-1500 dominate), but shines in continuous or hybrid process environments.

Advantages & Value

• Reduced integration risk — Pre-certified drivers for major field devices (Emerson DeltaV, Yokogawa CENTUM VP, Honeywell Experion) mean fewer custom OPC wrappers or protocol converters.
• Lower TCO over 5+ years — While upfront cost sits above basic PLCs, the extended service life (ABB quotes 15-year obsolescence horizon), long warranty, and minimal need for external safety hardware add up.
• Stronger support continuity — Unlike some OEMs that sunset platforms after 7 years, ABB maintains firmware updates and spare parts for the PM820 series well beyond typical industry norms—this seems to be part of their DCS-aligned roadmap.
• Procurement flexibility — We stock core configurations (CPU, power, base chassis), so delivery is typically within one week. For custom I/O mixes, lead time rarely exceeds four weeks—even with full SIL documentation packages.

Installation & Maintenance

Install in a NEMA 12 or IP54-rated cabinet with ≥200 mm clearance above and below for convection cooling—forced air isn’t required unless ambient exceeds 55°C. Wiring must follow IEC 61000-6-2 for EMC; shielded twisted-pair is mandatory for analog signals longer than 10 m. Grounding should be single-point, tied to the main system earth bar—not the cabinet frame.

For maintenance: verify firmware version every 6 months (ABB releases patches ~2x/year for security and stability); clean air filters quarterly if installed in dusty environments; calibrate analog inputs annually using certified reference sources. No routine battery replacement needed—the real-time clock is powered by supercapacitor, not lithium cells.

Quality & Certifications

The PM820 carries CE (EMC & LVD), UL 508A (Industrial Control Equipment), ATEX II 2G Ex db IIB T4 Gb (for Zone 1 hazardous areas), and IECEx certification. It’s RoHS 3 compliant and manufactured under ISO 9001:2015 and ISO 14001:2015. ABB provides a standard 365-day warranty covering parts and labor—extended coverage up to 5 years is available upon request, including remote diagnostics support.

Our order placement process: 50% advance payment secures build slot and expedites documentation; balance due before dispatch. In-stock units ship within 1 week via FedEx/UPS/DHL (tracking provided). Non-stock configurations ship within 4 weeks maximum—no exceptions. All units are pre-tested with loop-check reports included.