The scope of this deliverable is to analyze the process of data acquisition, filtering, pre-computing and typical data acquisition tools for data delivered at the external interfaces and functions supported. It is the first of three deliverables targeted on data acquisition within the PROTEUS project. This Deliverable D3.1 is focused on the definition of objects representing data acquired through the use of field and automation level equipment such as field devices, DCS, PLC, SCADA, Condition Monitoring Systems to be provided to the other components of the PROTEUS platform. This deliverable D3.1 will first start with the presentation of terms and definitions used in this document followed by the requirements specification on the data acquisition in maintenance. Chapter 5 will focus on basic data acquisition, condition monitoring and data pre-processing functions. Within chapter 6 typical data acquisition components used in automation will be analyzed for data delivered and functions supported. Finally a first version of a structured data model to describe the maintenance related view of equipment through „automation components will be defined which will be extended within D3.2. At the end of the document annexes are extensively used to provide examples of automation components, to discuss state of the art in data acquisition in the railway branch and to present some considerations on ontologies.