Take a look at the ISA/IEC 62443 Series of Standards
The ISA/IEC 62443 series of standards define requirements and processes for implementing and maintaining electronically secure #industrial automation and control systems (IACS). These standards set best practices for security and provide a way to assess the level of security performance. Their approach to the cybersecurity challenge is a holistic one, bridging the gap between operations and information technology as well as between process safety and cybersecurity.
The ISA/IEC standards set #cybersecurity benchmarks in all industry sectors that use IACS, including building automation, electric power generation and distribution, medical devices, transportation, and process industries such as chemicals and oil and gas.