Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Cyber-Physical Systems and Internet of Things



Christopher Greer, Martin J. Burns, David Wollman, Edward Griffor


This NIST Special Publication describes the relationship between the phrases "cyber-physical systems" and "Internet of Things." CPS and IoT both refer to trends in integrating digital capabilities, including network connectivity, with physical devices and systems. This document describes the origins of these terms, analyzes the range of definitions over time, describes a unified perspective, and explores implications of this perspective. Four categories of overlap were identified in publications comparing and contrasting CPS and IoT. The distinctions hinge on three issues: control, internet, and human interactions. The lack of consistent distinguishing metrics and the convergence of definitions indicate an emerging consensus around the equivalence of CPS and IoT concepts. This convergence creates opportunities for progress through integrating the research, innovation, and standards efforts of the respective communities. Two models provide the bases for a unified CPS/IoT perspective. A unified components model provides 4 categories for CPS and IoT systems components: logical, physical, transducing, and human. A unified interactions model provides a formal basis for describing the performance of CPS and IoT systems. The unified perspective can be expressed as follows: Internet of Things and Cyber-Physical Systems comprise interacting logical, physical, and human components engineered for function through integrated logic and physics. Three criteria based on a characteristic set of components, capabilities, and functions are proposed for interchangeably labeling a system ‘CPS' or ‘IoT'. Implications of a unified CPS and IoT perspective include the need for new hybrid discrete and continuous methods as science and engineering foundations for CPS/IoT design, operation, and assurance; and the importance of tight logical-physical linkage as the basis for the transformational nature of CPS/IoT systems.
Special Publication (NIST SP) - 1900-202
Report Number


CPS, Cyber-Physical Systems, IoT, Internet of Things, Definition, Standards


Greer, C. , Burns, M. , Wollman, D. and Griffor, E. (2019), Cyber-Physical Systems and Internet of Things, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 25, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created March 6, 2019, Updated March 1, 2021