AVINE Video System

evnAgent - event number agent

Maintainer: Stefan Weisse

Overview

Figure: Overview of Event Number Distribution Including evnAgent Component.

An important criterion for exact correlation of a beam image at a facility using triggered acquisition like PITZ is a so-called general event number. Each shot of the accelerator gets a unique event number assigned, which in general is transported to individual controls subsystems and experiment's properties are tagged with that event number. Afterwards, the data is transferred to the DAQ system. Later on, the physicist will require the event number to collect data that belong to an individual shot of the accelerator. A lightweight solution has been developed and installed at PITZ, which makes use of distributing the event number from a central timing source throughout the controls network. On the server level, the SGP component with the help of an 'event number Agent' component (evnAgent), tags each freshly acquired video image with the event number.

Workflow of evnAgent

• receives ZeroMQ Time Telegram packets (ZeroMQ Multicast transport has been superseded by TCP) consisting of general event number and associated global timestamp
• receives repetition rate from central timing via control system property
• provides shared memory to local listeners (SGP components) for updates of event number plus associated timestamp and repetition rate
• contains logging to output received time telegram packets outside of an expected interval based on the current repetition rate (10 Hz -> 90 to 110 ms)
• automatic restart of ZeroMQ connection in case of lost connection to ZeroMQ sender

XML Configuration File

Please consult XML Configuration files documentation located on a separate page.