A multi-purpose user interface for the iFDAQ of the COMPASS experiment

In HEP experiments, remote access to control systems is one of the fundamental pillars of efficient operations. At the same time, development of user interfaces with emphasis on usability can be one of the most labor-intensive software tasks to be undertaken in the life cycle of an experiment. While desirable, the development and maintenance of a large variety of interfaces (e.g., desktop control interface, web monitoring interface, development API...) is often simply not feasible, as far as manpower is concerned. We present a solution employed in the control software of the iFDAQ of the COMPASS experiment at CERN. Being a mix of a command-line and terminal tool, this interface can fulfill the roles of a dynamic monitoring interface, a control interface, and a scripting API simultaneously. Furthermore, it can easily be used as a remote access tool for operations experts, needing nearly no setup user-side and being compatible with smartphones. We also discuss the methodology and results of a concrete use case – automated run control for performance tests of the iFDAQ readout software.

The Online Monitoring API for the DIALOG Library of the COMPASS Experiment

Modern experiments demand a powerful and efficient Data Acquisition System (DAQ). The intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN is composed of many processes communicating between each other. The DIALOG library covers a communication mechanism between processes and establishes a communication layer to each of them. It has been introduced to the iFDAQ in the Run 2016 and improved significantly the stability of the system. The paper presents the online monitoring API for the DIALOG library. Communication between processes is challenging from a synchronization, reliability and robustness point of view. Online monitoring tools of the communication between processes are capable to reveal communication problems to be fixed in future. The debugging purpose has been crucial during introduction period to the iFDAQ. On the other hand, based on the measurement of communication between processes, the proper load balancing of processes among machines can improve the stability of the system. The online monitoring API offers a general approach for the implementation of many monitoring tools with different purposes. In the paper, it is discussed its fundamental concept, integration to a new monitoring tool and a few examples of monitoring tools are given.

The Continuously Running iFDAQ of the COMPASS Experiment

Recently, a stability of Data Acquisition System (DAQ) has become a vital precondition for a successful data taking in high energy physics experiments. The intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN is designed to be able to readout data at the maximum rate of the experiment and runsin a mode without any stops. DAQ systems fulfilling such requirements reach the efficiency up to 99%. The newly introduced continuously running mode enables to collect data without a necessity of any other user intervention.Such mode affects all processes of the iFDAQ with high emphasis on timing and precise synchronization. However, every undesirable interruption of data taking can potentially result in a possible loss of physics data. Running24/7 puts stress on reliability and robustness of the system. Therefore, the improvement of the iFDAQ stability had to come first. The continuously running mode and the improved iFDAQ stability helped to collect more physicsdata in the Run 2017. In the paper, we present the continuously running mode in more detail and discuss the overall iFDAQ stability.