PM875-2 3BDH000606R1 AC 870P – PM 875 Controller

The PM 875 controller is a member of the Extended Automation System 800xA family.
The PM 875 controller uses a 32 bit processor for maximum computing power and modular
scalability. The integrated redundant PROFIBUS interface provides connectivity to ABBs I/O families S800 and S900 and to other
PROFIBUS devices. HART communication is system integrated, including configuration and diagnostic through the control network. The
PM 875 controller is fully compatible to former Melody solutions, thus naturally allowing reuse of the comprehensive portfolio of I/O modules and communication interfaces. It seamlessly
integrates into the control network. The network is easy to handle and does not need any routing configuration.

PM875-2

A unit CPU redundant controller is a controller with redundant functions that is used to implement backup and

failover functions in a system. It usually consists of two or more processing units, each of which can perform

control tasks independently. When one processing unit fails, the backup processing unit can take over control tasks to ensure system stability and availability.

Such controllers are commonly used in systems that require high reliability and uninterrupted control, such as

industrial automation, aerospace, medical equipment, and more. In a unit CPU redundancy controller, the

processing units can be the same or different models and can be based on the same or different operating systems or software platforms.

There are several key factors to consider when implementing a unit CPU redundancy controller:

Redundant design: Design backup processing units so that they can seamlessly take over control tasks in the

event of a primary processing unit failure.
Fault detection and switching mechanisms: A fault detection mechanism is designed to detect faults in the main

processing unit and trigger switching operations if needed.
Data synchronization and sharing: Ensure data synchronization and sharing between the backup processing

unit and the primary processing unit so that continuity of control tasks can be maintained when switching.
Maintenance and management: Provides easy maintenance and management functions to configure, monitor, and manage redundant controllers.
In short, the unit CPU redundancy controller is a highly reliable controller that provides backup and failover

functions to ensure the stability and availability of the system.