OPC 10000-1, OPC Unified Architecture - Part 1: Overview

OPC 10000-3, OPC Unified Architecture - Part 3: Address Space Model

OPC 10000-5, OPC Unified Architecture - Part 5: Information Model

OPC 10000-6, OPC Unified Architecture - Part 6: Mappings

OPC 10000-9, OPC Unified Architecture - Part 9: Alarms and Conditions

DIN IEC 61131-3:2009-12, Programmable Controllers – Part 3: Programming languages

OPC 10030, UA Companion Specification for ISA-95 Common Object Model