The PM875-2 is a discontinued controller used by ABB in its extended automation system 800xA. Here's what we know about PM875-2:
Features:
Process control logic and execute automation programs.
Monitor and control various industrial processes in the 800xA system.
Communicate with other system components and I/O modules.
Features (based on available information):
32-bit Intel Pentium mobile CPU Powerful processing.
Modular design, can be expanded according to application requirements.
Redundant Ethernet interface for reliable communication.
Supports multiple communication protocols, such as PROFIBUS, Fnet and Cnet, and can be integrated with different devices.
Run the ac870p operating system specifically designed for industrial automation.
Application program:
Industrial process control (manufacturing, power generation, oil and gas, etc.)
Factory automation
Building automation
Alternative options:

.ABB's PM875-2 is a controller that is part of the 800xA series of automation systems specifically designed to extend automation systems. The controller uses a 32-bit processor, which provides the system with powerful computing power and modular scalability. It integrates redundant PROFIBUS interfaces to enable connectivity with fieldbus devices such as ABB's I/O series S800 and S900. In addition, the PM875-2 controller has HART communication, which facilitates system integration, including configuration and diagnostics through the control network.
The controller is fully compatible with the previous solution, so it can reuse a comprehensive combination of I/O modules and communication interfaces. It can be seamlessly integrated into the control network, making the processing of the network simpler, without the need for complex routing configuration.

