This document defines the OPC UA MDIS companion specification. This standard is an Oil and Gas standard for interfacing the Subsea Production Control System (SPCS), with a Master Control Station (MCS) or a Subsea Gateway, to the Distributed Control System (DCS). This specification includes:

• A description of common terms,
• Supported architectures,
• Information models representing the data that is shared between the systems,
• Methods used in the flow of information,
• Profile & ConformanceUnits describing the grouping of functionality,
• Recommended Practices for the use of MDIS.

MDIS was created to define a standard object model that is transported on a common high performance efficient interface between topside and subsea systems in Oil and Gas installations. The selected protocol (OPC UA) includes independent third-party certification.