OPC Specifications

	OPC Data Access (OPC DA) OPC Data Access, or just OPC DA, provides a standard way to access real-time data from process control hardware and software. Click here to learn more. OPC Data Access Specification 3.0 [PDF 7,138 kb].

	OPC Historical Data Access (OPC HDA) OPC Historical Data Access, known as OPC HDA, standardizes communication for retrieving archived process data and provides the solution for accessing historical data across multiple vendors. Click here to learn more. OPC Historical Data Access Specification 1.2 [PDF 6,425 kb].