DAQ Actors & Scenarios

  • Run Control
  • Event Builder (server & clients)
  • Message Logger
  • Error Handler
  • Resource Manager
  • Configuration Manager (?)
  • Data Logger (receives data from EVBs)
  • Trigger Manager (SW or HW that defines which data should be saved)
  • Slow Controls
  • DAQ Monitor System (e.g. Ganglia)
  • DAQ Quality Monitor

Run Control

Purpose: Configure and control state of all components in a partition.

  • Broadcasts a state change (transition) to all resources in the partition
  • Collects transition acks from all resources in partition
  • Detects missing transition ack from one or more resources
  • Sends transitions to specific resources in partition
  • Sends configuration to resources in partition

Event Builder

Purpose: Collect data from front-ends and assemble a complete event. May have different behavior depending on the type of the experiment. E.g. on Nova the Event Builder must select data that fits a trigger window, while at CDF/D0 the Event Builder does not need to find data, just needs to put together the event pieces.

  • Server connects to client
  • Server connects to Data Logger
  • Server receives data from client
  • Server constructs events from client data
  • Server sends complete event to Data Logger

Message Logger

Purpose: Provide an interface for DAQ application to send messages (error, warning, information). Messages are logged in some type of database and can also be displayed at real time for operators. Messages can be filtered and throttled.

  • Resource produces message
  • Message is sent to Message Logger
  • Message Logger saves message in database
  • Message Logger displays message
  • Messages are retrieved from database

Error Handler

Purpose: Implement recovery actions based on error messages from DAQ components.

  • Receives error message from resource(s)
  • Requests pause/end of run based on error messages
  • Initiates recovery action based on error messages

Resource Manager

Purpose: Maintain a record of which resources belong to which partitions, avoiding conflicts over a resource.

  • New resources are added to the Resource Manager database
  • Receives request for a partition
  • Receives request to add a resource to a partition
  • Receives request to remove resource from a partition

Configuration Manager

Data Logger

Trigger Manager

Slow Controls

DAQ Moniton System

DAQ Quality Monitor


  • Resource: hardware or software entity capable of responding to Run Control commands. May belong to the data and/or control paths.
  • Partition: independent set of resources following commands and configuration from the same Run Control instance