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What is a SCADA system in simple terms?
SCADA (Supervisory Control and Data Acquisition) is a software and hardware system that continuously collects measurement data from spatially distributed industrial plants, visualises it on screens in a control room and allows operators to intervene in pumps, valves or machines. It forms the supervisory and monitoring level above machine-level control technology and thus serves as the central cockpit for large technical facilities. Characteristic is the combination of higher-level control and systematic data archiving. Fast real-time control in the millisecond range remains in the subordinate controller, not in the supervisory system.
What is the difference between SCADA and a PLC?
A PLC (programmable logic controller, in German SPS) directly controls and regulates individual machines or plant sections and operates deterministically in the millisecond range. SCADA sits one level above, aggregates multiple PLCs as well as remote terminal units and displays their status on operator screens in a control room. The supervisory system enables higher-level interventions, alarm management and the long-term archiving of process values across entire plant networks. SCADA is therefore not a single controller but a plant-wide visualisation and monitoring layer.
In which industries is SCADA used?
SCADA is classically used wherever spatially distributed technical facilities need to be monitored and controlled centrally. Typical fields of application are water supply and wastewater treatment, power generation and electricity grids, oil and gas pipelines as well as the chemical, pharmaceutical and food industries. SCADA systems are also widespread in large production lines and in building management systems. Many of these areas of use count as critical infrastructure, which is why availability and resilience are particularly important here.
How does SCADA fit together with an ERP system?
SCADA and ERP work on different levels: SCADA knows the real technical state of the plant in real time, while the ERP plans and posts orders, material requirements and costs from a business perspective. A direct coupling is rare; in practice an MES (Manufacturing Execution System) is usually placed in between, condensing machine and process data and passing it to the ERP as key figures. This tiered architecture corresponds to the widely used automation model and belongs to the Industry 4.0 topic area. A graduated data concept is recommended that passes only the information actually needed to the ERP via a clean interface.
Which SCADA software is most widespread on the market?
In the DACH region and internationally, Siemens with its WinCC product ranks among the market-leading vendors, followed by AVEVA InTouch (formerly Wonderware, fully owned by Schneider Electric since early 2023), zenon from COPA-DATA and Ignition from Inductive Automation. In addition, other large automation manufacturers such as ABB, Rockwell Automation and Honeywell are active at group level. Analysts estimate the global SCADA market at around 12 billion US dollars for 2025, with projected annual growth rates ranging from the high single digits to the low double digits in percentage terms depending on the source. Open-source solutions such as Rapid SCADA are occasionally found in smaller or cost-sensitive installations; precise market shares of individual products are, however, only of limited reliability.
What role does cybersecurity play in SCADA systems?
Cybersecurity is a high priority for SCADA, as the formerly isolated operational networks are increasingly connected to IT systems and the internet, thereby becoming an attack surface. For operational technology (OT), the IEC 62443 series of standards is regarded as the authoritative international standard; among other things, it recommends segmentation into zones and conduits, strict access controls and well-thought-out patch management. Operators of critical infrastructure in the EU are additionally subject to regulatory requirements such as the NIS 2 Directive, which demands risk management, reporting obligations and evidence. A clear separation of responsibilities between operational technology and IT is considered good practice.
Which protocols does a SCADA system communicate over?
SCADA systems exchange data via industrial communication protocols, some of which have been established for decades. Modbus originally dates back to 1979 and Modicon and is still widely used, while DNP3 was developed in the early 1990s specifically for utility and energy applications. OPC UA is increasingly gaining ground as a vendor-independent, platform-neutral standard that enables uniform and secured data exchange. In IoT and cloud-related scenarios, the lightweight MQTT protocol is additionally used, which eases the connection to higher-level systems such as MES and ERP.