PM891K02 | ABB AC 800M Redundant Processor Unit

Product Overview

The ABB PM891K02 (3BSE053242R1) is a redundant high-performance Processor Unit Kit featuring two PM891 CPUs. It delivers the highest available AC 800M performance with hot-standby redundancy for critical automation infrastructure.

Key Specifications

• Manufacturer: ABB
• Part Number: PM891K02 (3BSE053242R1)
• Product Type: AC 800M Redundant Processor Unit Kit
• CPU: 2× MPC8270 @ 450 MHz
• Memory: 256 MB DDR2 SDRAM per CPU
• Performance: 0.043 ms per 1000 boolean operations; ~3× PM864A per CPU
• Redundancy: Hot-standby CPU, CEX-Bus, RCU Control & Data Links
• Switchover Time: Max 10 ms
• System: AC 800M / System 800xA
• Kit Includes: 2× PM891K01 Processor Unit, 1× TK850V007 CEX-Bus Extension Cable, 1× TK855 RCU Data Link Cable, 1× TK856 RCU Control Link Cable
• Note: BC810K02 is not included and must be ordered separately for hot replacement capability
• Power Supply: 24 V DC (19.2–30 V DC)

Applications

• Critical power plant control
• Large refinery DCS
• Integrated process-safety systems
• High-availability manufacturing

FAQ

Q: What redundancy links does PM891 use?
A: PM891 uses TK855 RCU Data Link and TK856 RCU Control Link (dual redundancy links), unlike other PM8xx which use a single TK851 RCU Link.

Q: Can PM891K02 be mixed with other CPU types?
A: No, redundant pairs must be identical processor models and firmware revisions.

Q: Why is BC810K02 required separately?
A: BC810K02 CEX-Bus Interconnection Unit is required to enable hot replacement of PM891 processor units. It is not included in the PM891K02 kit and must be ordered separately.

Installation Guide

1. Mount both PM891 units on DIN rail with adequate spacing for ventilation.
2. Connect TK855 RCU Data Link and TK856 RCU Control Link between the two units.
3. Install BC810K02 on TP857 if hot replacement is required.
4. Wire independent 24 V DC power to each unit.
5. Connect control network Ethernet to both units.
6. Configure redundancy in Control Builder M.

Selection Tips

• PM891K02 is the top-tier choice for performance and availability.
• Verify software version supports PM891 redundancy.
• Use optical ModuleBus for I/O; electrical ModuleBus is not available on PM891.
• Remember to order BC810K02 separately for hot replacement capability.