Operational technologies, often referred with the acronym OT, is hardware and software that detects or causes a change, through the direct monitoring and/or control of industrial equipment, assets, processes and events.
The industrial context is basic on this definition of OT. OT is often used as a counterpart of information technologies (IT), to refer the technologies that are used in an industrial environment.
Terms that are usually used in OT context
SCADA is the acronym of Supervisory Control And Data Acquisition. It is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes.
Programmable Logic Controller (PLC) is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis.
Human-Machine Interface (HMI) is a user interface or dashboard that connects a person to a machine, system, or device.
Industrial Control System (ICS) is an electronic control system and associated instrumentation used for industrial process control.
In the CIA triad (confidentiality, integrity and availability), OT focuses on availability while IT focuses on confidentiality and integrity.
You may have a look at this brochure about ICMS (Industrial Cybersecurity Management System) requirements, issued by CCI (Centro de Seguridad Industrial). You can download it from this link.
The non-profit organization ISMS Forum, in collaboration with the Oficina de Seguridad Cibernética (OCC) and Home Office of Spain issues a guide on security controls in OT systems. It links controls from standards ISO/IEC 27002 and IEC 62443. You can download it from this link., and it is available in English and Spanish.