As an emerging Service Oriented Architecture (SOA) speciﬁcally designed for industrial automation and process control, the OPC Uniﬁed Architecture speciﬁcation should be regarded as an attractive candidate for controlling scientiﬁc instrumentation. Even though an industry-backed standard such as OPC UA can oﬀer substantial added value to these projects, its inherent complexity poses an important obstacle for adopting the technology. Building OPC UA applications requires considerable eﬀort, even when taking advantage of a COTS Software Development Kit (SDK). The OPC Uniﬁed Architecture Framework (UAF) attempts to reduce this burden by introducing an abstraction layer between the SDK and the application code in order to achieve a better separation of the technical and the functional concerns. True to its industrial origin, the primary requirement of the framework is to maintain interoperability by staying close to the standard speciﬁcations, and by expecting the minimum compliance from other OPC UA servers and clients. UAF can therefore be regarded as a software framework to quickly and comfortably develop and deploy OPC UA-based applications, while remaining compatible to third party OPC UA-compliant toolkits, servers (such as PLCs) and clients (such as SCADA software). In the ﬁrst phase, as covered by this paper, only the client-side of UAF has been tackled in order to transparently handle discovery, session management, subscriptions, monitored items etc. We describe the design principles and internal architecture of our open-source software project, the ﬁrst results of the framework running at the Mercator Telescope, and we give a preview of the planned server-side implementation.