The Metso PDP603 is a robust distributed processing unit designed for the Metso DNA (now Valmet DNA) automation system. It serves as a crucial link in a distributed control system (DCS), handling process control and I/O tasks locally. By distributing processing power closer to the field devices, the PDP603 enhances system responsiveness, reliability, and fault tolerance. It communicates with the system network and local I/O modules, executing control loops and logic independently. This architecture ensures continuous operation even if communication with the central server is temporarily interrupted, making it an ideal solution for critical process control applications in industries such as pulp and paper, energy, and chemical processing.