According to the ISA/IEC 62443-1-1 standard, an industrial automation and control system (IACS) is defined as a collection of personnel, hardware, and software that can affect or influence the safe, secure, and reliable operation of an industrial process. The hardware and software components of an IACS include the control system, which is the combination of control devices, networks, and applications that perform the control functions for the industrial process. The control system may consist of various types of devices, such as distributed control systems (DCS), programmable logic controllers (PLC), supervisory control and data acquisition (SCADA) systems, human-machine interfaces (HMI), remote terminal units (RTU), intelligent electronic devices (IED), sensors, actuators, and other field devices. The control system may also use commercial off-the-shelf (COTS) software and hardware, such as operating systems, databases, firewalls, routers, switches, and servers, to support the control functions and communication.
References:
ISA/IEC 62443-1-1:2009, Security for industrial automation and control systems - Part 1-1: Terminology, concepts and models, Clause 3.2.11
ISA/IEC 62443-2-1:2010, Security for industrial automation and control systems - Part 2-1: Establishing an industrial automation and control systems security program, Clause 3.2.12
