Events Processing in the New DAQ of the COMPASS Experiment

This paper describes the route of events through both hardware and software parts of the data acquisition system (DAQ) of the COMPASS experiment at CERN which implements FPGA based event-building. Data quality control is important part of any DAQ. During development of the COMPASS DAQ, a great emphasis was put on ability to recover from errors coming from frontend electronics and on possibility to easily identify origin of errors. Many tests are performed and additional headers are added to data stream by hardware. These headers are later analyzed by software. System was tested for the first time during run in the end of year 2014. Run was successful, but further improvements are planned.