SCADA vs DCS vs PLC: Differences, Uses and How to Identify Them
Feature image: a PLC controls a machine, a DCS controls a whole plant, and SCADA supervises many sites. Conceptual illustration, not a vendor architecture. SCADA, DCS and PLC are three of the most confused acronyms in industrial automation, and the confusion has a simple cause: they are not three rival products. A PLC (programmable logic controller) is a device that runs control logic. A DCS (distributed control system) and SCADA (supervisory control and data acquisition) are systems , and PLCs are used inside both of them. This guide explains what each one is, where each is used, how they differ, and, because it is the question that matters on site, how to tell from the system itself whether you are looking at a SCADA or a DCS. The practical stakes are real. A technician who calls a plant-wide control system "SCADA" when it is a DCS will search the wrong documentation. A project engineer who specifies a PLC where a DCS is needed will discover the gap in alarm handling, red...