Description
🔧 Product Overview
The ABB PM891K02, article number 3BSE053242R1, is a Redundant Processor Unit for the ABB AC 800M automation platform. It is designed for applications where controller redundancy and higher system availability are required.
Unlike a single PM891K01 processor, the PM891K02 package contains two PM891K01 processor units together with the cables required for redundant controller communication. ABB specifies a 450 MHz processor and 256 MB memory for the PM891 platform.
The PM891 architecture integrates the CPU, memory, power supply and termination functions into the processor unit. It provides redundant Ethernet communication, CEX-Bus expansion, and optical ModuleBus connectivity for AC 800M I/O systems.
⚙️ Main Features
- ABB AC 800M controller hardware
- PM891K02 redundant processor package
- ABB article number 3BSE053242R1
- Two PM891K01 processor units included
- 450 MHz processing speed
- 256 MB memory
- CPU redundancy for increased availability
- Redundant Control Unit architecture
- Two built-in Ethernet ports
- CEX-Bus communication expansion
- Optical ModuleBus support
- Service/configuration RS-232 interface
- Compact rail-mounted AC 800M architecture
- Suitable for System 800xA automation installations
📋 Product Datasheet
| Parameter | Specification |
|---|---|
| Brand | ABB |
| Model | PM891K02 |
| Article Number | 3BSE053242R1 |
| Product Type | Redundant Processor Unit |
| Automation Platform | AC 800M |
| System | ABB System 800xA / AC 800M |
| Redundancy | Yes |
| High Integrity | No |
| Processor | MPC8270 |
| Clock Frequency | 450 MHz |
| Memory | 256 MB |
| RAM Available for Application | Approx. 208.985 MB |
| Flash Memory | 16 MB firmware storage |
| Performance | 0.043 ms / 1,000 Boolean operations |
| Redundant Switch-Over | Max. 10 ms |
| Power Supply | 24 VDC |
| Permitted Supply Range | 19.2–30 VDC |
| Typical / Maximum Current | 660 / 750 mA |
| Power Dissipation | 15.8 W / 18 W max. |
| Ethernet Ports | 2 × 10/100 Mbit/s |
| Ethernet Function | Control Network |
| CEX-Bus | Supported |
| RS-232 | 1 × service/configuration interface |
| ModuleBus | Optical ModuleBus |
| I/O Capacity | Up to 84 modules |
| Package | 2 × PM891K01 + TK850V007 + TK855 + TK856 |
| Dimensions | 174 × 186 × 94 mm |
| Package Weight | Approx. 4.0 kg |
| Protection | IP20 |
| Condition | New / New Surplus subject to actual inventory |
The electrical and performance values above are taken from ABB’s current PM891K02 data sheet.
🔄 Redundant Controller Architecture
The PM891K02 is intended for applications where losing a single processor should not interrupt the control system.
The package contains:
- 2 × PM891K01 Processor Units
- 1 × TK850V007 CEX-Bus Extension Cable
- 1 × TK855 RCU Data Link Cable
- 1 × TK856 RCU Control Link Cable
ABB specifically states that the BC810K02 is not included in the PM891K02 package. BC810K02 is required when hot replacement of the PM891 processor unit is needed.
🌐 Ethernet & Communication
Each PM891 provides two RJ45 Ethernet ports for the AC 800M Control Network. The ports support 10/100 Mbit/s Ethernet communication.
The controller also includes a CEX-Bus for expanding the available communication interfaces. ABB specifies support for up to 12 communication modules on the CEX-Bus.
A separate isolated RS-232 service interface is provided for configuration and service-tool access.
🧩 AC 800M I/O Integration
The PM891 supports the optical ModuleBus architecture used with ABB S800 I/O.
ABB specifies up to seven optical I/O clusters, with each cluster capable of accommodating up to 12 I/O modules. The documented maximum ModuleBus capacity is 84 modules.
This makes the PM891K02 suitable for larger distributed control applications where the controller must communicate with multiple remote I/O groups.
⚡ Power Supply
The processor operates from a 24 VDC control supply with a permitted range of 19.2–30 VDC.
ABB specifies:
- Typical current: 660 mA
- Maximum current: 750 mA
- Typical power dissipation: 15.8 W
- Maximum power dissipation: 18 W
The PM891 also provides a redundant power-supply status input for monitoring the power arrangement.
🏭 Typical Applications
The PM891K02 can be used in AC 800M control architectures for:
- Process automation
- Distributed control systems
- System 800xA installations
- Power and energy automation
- Chemical and petrochemical plants
- Water and wastewater systems
- Manufacturing processes
- Large machine-control systems
- Continuous-process industries
- High-availability control applications
The main reason to select the K02 version is controller redundancy rather than simply additional processing capacity.
🔩 Installation & Configuration
Before replacement, confirm the complete part number 3BSE053242R1 and verify that the existing controller uses the PM891 architecture.
Recommended procedure:
- Record the existing controller configuration.
- Verify the PM891K02 article number.
- Check the firmware and application configuration.
- Confirm the CEX-Bus and RCU connections.
- Verify the 24 VDC supply.
- Follow the site’s controller shutdown and isolation procedure.
- Install the redundant processor units and interconnection cables.
- Check Ethernet network connections.
- Verify RCU data/control connections.
- Restore the configuration and check controller redundancy.
- Confirm communication with the connected I/O system.
- Review controller diagnostics before returning the system to service.
For a live AC 800M installation, firmware, controller configuration, redundancy settings and application compatibility should be checked before replacing processor hardware.
🔄 Compatibility & Replacement Notes
PM891K02 belongs to the AC 800M processor family. ABB lists PM891K01 as the corresponding single processor unit and PM891K02 as its redundant processor package.
Related processor families include:
- PM866AK01 / PM866AK02
- PM867K01 / PM867K02
- PM862K01 / PM862K02
- PM863K01 / PM863K02
- PM858K01 / PM858K02
- PM857K01 / PM857K02
- PM891K01 / PM891K02
These models are not automatically interchangeable. CPU generation, memory, redundancy capability, firmware and system configuration must be checked before substitution.
❓ Frequently Asked Questions
Q: What is ABB PM891K02?
A: It is a redundant processor unit package for the ABB AC 800M automation platform.
Q: What is the ABB article number?
A: 3BSE053242R1.
Q: How many processor units are included?
A: The standard PM891K02 package contains two PM891K01 processor units.
Q: What processor speed does the PM891 use?
A: ABB specifies a 450 MHz MPC8270 processor.
Q: How much memory does it have?
A: The PM891 platform has 256 MB of memory, with approximately 208.985 MB available for application RAM according to ABB’s current data sheet.
Q: Does PM891K02 support CPU redundancy?
A: Yes. Redundancy is the defining function of the K02 package.
Q: Is BC810K02 included?
A: No. ABB specifically states that BC810K02 must be ordered separately when hot replacement is required.
Q: Can PM891K01 replace PM891K02 directly?
A: A PM891K01 is the individual processor unit used inside the PM891K02 package, but it does not by itself provide the complete redundant processor package.
🔧 Recommended ABB AC 800M Models
- ABB PM891K01 – 3BSE053241R1 Processor Unit
- ABB PM891K02 – 3BSE053242R1 Redundant Processor Unit
- ABB PM866AK01 – Processor Unit
- ABB PM866AK02 – Redundant Processor Unit
- ABB PM867K01 – High-Integrity Processor Unit
- ABB PM867K02 – High-Integrity Redundant Processor Unit
- ABB PM862K01 – Processor Unit
- ABB PM862K02 – Redundant Processor Unit
- ABB PM863K01 – High-Integrity Processor Unit
- ABB PM863K02 – High-Integrity Redundant Processor Unit
ABB’s AC 800M hardware selector currently lists these processor families together, including their respective memory, performance and redundancy characteristics.
🧪 Inspection Before Shipment
For a PM891K02 spare package, recommended inspection includes:
- Complete part-number verification
- PM891K02 identification
- 3BSE053242R1 verification
- Processor unit quantity check
- PM891K01 identification
- Cable and accessory verification
- Ethernet port inspection
- CEX-Bus connector inspection
- RCU connection inspection
- Housing and mounting inspection
- Label and serial-number recording
- Visual inspection for corrosion or physical damage
- Power-up and diagnostic testing where test equipment is available
- ESD-safe packaging
- Final QC documentation
Important: PM891K02 is a complete redundant processor package, not simply a single CPU module. When purchasing a replacement, confirm whether the required package should contain the two PM891K01 units and the TK850V007, TK855 and TK856 cables. ABB’s official documentation confirms this package configuration.
