Online Monitoring for DDT

Vanilla OnMon

The OnlineMonitoring package, or OnMon for short, is a system which performs quick, automated analysis of NOvA data. This allows us to have an up-to-date snapshot of the health of the detectors and data. It's proven time and again to be a very successful system, which is why its associated viewer is one of the most used windows in the control room. Additionally, OnMon permits the creation of the nearline plots, which are the result of secondary analysis of OnMon's output and provide even more ways to gauge the experiment's well-being. Nearline plots are accessible online, which makes them a common first stop when checking on the experiment.


While OnMon is well-suited for checking the status of NOvA's primary physics goals, it has proven to be difficult, and sometimes impossible, to adapt to DDT's monitoring needs in its current form. Because of this, a fork of OnMon called DDT OnMon has been created. This has involved extensive changes, which are documented here. A brief set of changes from vanilla OnMon follows:
  • cut viewer
  • cut tracker monitoring
  • cut most hardware monitoring
  • added more subrun information to header
  • added trigger-specific histogram fillers
  • added filler for histograms of various time calculations
  • added support for TH3Fs
  • various changes to information subscribers, particularly at the event level

How It Works

In the future, this section will contain the step-by-step process by which DDT OnMon processes a set of raw files.