[en] The ATLAS experiment at CERN is one of the four Large Hadron Collider experiments. DCS Data Viewer (DDV) is a web interface application that provides access to historical data of ATLAS Detector Control System (DCS) parameters written to the database (DB). It has a modular and flexible design and is structured using a client-server architecture. The server can be operated stand alone with a command-line interface to the data while the client offers a user friendly, browser independent interface. The selection of the meta-data of DCS parameters is done via a column-tree view or with a powerful search engine. The final visualisation of the data is done using various plug-ins such as 'value over time' charts, data tables, raw ASCII or structured export to ROOT. Excessive access or malicious use of the database is prevented by dedicated protection mechanisms, allowing the exposure of the tool to hundreds of inexperienced users. The meta-data selection and data output features can be used separately by XML configuration files. Security constraints have been taken into account in the implementation allowing the access of DDV by collaborators worldwide. (authors)