The ROD Crate DAQ of the ATLAS Data Acquisition System

In the ATLAS experiment at the LHC, the ROD Crate DAQ provides a complete framework to implement data acquisition functionality at the boundary between the detector specific electronics and the common part of the data acquisition system. Based on a plugin mechanism, it allows selecting and using common services (like data output and data monitoring channels) and developing libraries to control, monitor, acquire data and/or emulate detector specific electronics. Providing also event building functionality, the ROD Crate DAQ is intended to be the main data acquisition tool for the first phase of detector commissioning. This paper presents the design, functionality and performance of the ROD Crate DAQ and its usage in the ATLAS data acquisition system and during detector tests.