Distributed Control System (DCS) can take you beyond the limits of your current process automation system by helping you to integrate your process infrastructure directly into the DCS; or by using common hardware and engineering tools for process automation, discrete control (high speed logic), process safety and batch control.

This increases the demand for diagnostic information on both the instrumentation and other process equipment to better diagnose and predict process problems so that corrective action can be planned.

DCSs are most often chosen for continuous, semi-continuous and batch process applications and applications where the analog I/O count is high.

On the other hand, PLCs typically cost less initially per I/O point but have, in general, less functionality and less redundancy. So, it’s a common choice for systems that are predominately discrete I/O with relatively fixed logic, and also for machine control and motion control where very high speed scanning is required.