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Virgo Data AcquisitionD. Verkindt, LAPP

• DAQ Purpose
• DAQ Architecture
• Data Acquisition examples

• Connection to DAQ and monitoring tools
• Data Streams
• Online analysis tools

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DAQ purpose

• DAQ requirements
• collection of distributed data (timing system,
  optical links)
• flexibility in data flow (frame format)
• reliability (at least 1 month without crash)
• easyness of use and restart (DAQ graphical
  client)

Laser
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DAQ purpose
Get data from various synchronized sources,
sometimes 3 km away
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DAQ purpose

• Collect distributed data from
• ITF environment
• ITF controls
• ITF output detection

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DAQ architecture
Environment Monitoring
Detection
Controls
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DAQ architecture
Environment Monitoring
Controls
Detection
Susp. Ctrl
Global Ctrl
Photodiodes
Alignement
Det. Bench Ctrl
Laser env towers tubes calib.itf
DOL
DOL
gt 30 VME crates
DOL
1 Gx
FbF
FbS
6 Gx
FbF
4 Fbf
FbF
3 Gx
FbS
FbS
frames
frames
frames
local Main Frame Builder
local Main Frame Builder
local Main Frame Builder
3.0 MB/s
3.3 MB/s
2.7 MB/s
Central Main Frame Builder
9 MB/s (compressed 4MB/s)
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DAQ architecture

• More than 30 VME crates, but a reduced set of
  standard tools
• Digital Optical Links (DOL) for controls
• Fast Ethernet and Gbit Ethernet for central
  data collection
• VME crates for front-end data acquisition
• Workstations for central data collection
• Standard format for data collection frames
  encapsulated in Ethernet messages

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Frame format
Frame elementary time slice of data

• Contains
• GPS time stamp
• ITF informations
• raw data channels
• processed data
• events

Common format of several gravitational waves
detectors
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Timing system overview

• Purpose
• Synchronization (of controls)
• Frame and sampling numbers
• GPS time stamp for data exchange

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Data acquisition examples
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Data acquisition examples
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Data acquisition examples
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Connection to DAQ

• Main Frame Builder
• Use shared memory and 2 processes
• Producer merge input frames
  and put result in shared memory
• Consumer read frames in shared memory
  and send them on network

Fast Frame Builders
Slow Frame Builder
Main Frame Builder
Producer
Shared Memory
Consumer 2
Consumer 1
Main data stream
DAQ world
Central Main Frame Builder
Online Processing
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Online Monitoring using dataDisplay
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Offline use of dataDisplay
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DAQ control and monitoring
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Web DAQ Monitoring
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DAQ Performances

• Run almost continuously since Sept. 2001
• DAQ efficiency during last engineering runs gt
  99.8
• Minimized latency --gt DAQ can be used for online
  control

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Current data streams
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Trend data acquisition
Controls Frame Builder
Detection Frame Builder
Env. Moni Frame Builder
Main Frame Builder
Full Frame Storage (disks)
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Online Monitoring using trend data
Use of Vega tool and Web browser
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Offline use of trend data
Example 2 max of output of ITF, building temp.
and seismic motion near north tower over 3 days
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50Hz data acquisition
Controls Frame Builder
Detection Frame Builder
Env. Moni Frame Builder
Main Frame Builder
Full Frame Storage (disks)
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Online monitoring using 50 Hz data
Example 1 monitoring of seismic activity over 8
hours, in 3 frequency bands
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Offline use of 50 Hz data
Example 2 spectral density of output of ITF
over 3 hours of data (made in 30 sec)
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Online analysis tools

• GAI (General Algorithm Interface)
• A software tool to interface algorithms to
  online processing stream of data.
• Used to run online algorithms during engineering
  runs
• Used also offline to analyse engineering runs
  data
• Improved thanks to requests and comments from
  users and algorithm developers

• Some of the algorithms developed up to now with
  GAI for online and offline analysis
• Algorithm 1 monitoring of spectral lines in
  ITF output channels
• Algorithm 2 search of glitches in ITF output
  channels
• Algorithm 3 monitoring of the stationarity and
  gaussianity of the ITF output.

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Online analysis tools
Ethernet
Disk
Shared Memory
frames
GAI process
Algorithm
Gai library
frames
Shared Memory
Disk
Ethernet
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Online analysis tools
Ethernet
Algorithm1
Disk
Algorithm4
Shared Mem
Shared Mem
Algorithm2
Algorithm3
Ethernet
Algorithm5
Disk
data under frame format
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Online Analysis current scheme
Online Processing Frame Distributor
Main Frame Builder
frames
raw data frames
Full Frame Storage (disks)
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Online Analysis futur scheme
Main Frame Builder
Trigger manager
frames
raw data frames
Full Frame Storage (disks)
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Conclusion
Virgo DAQ and online monitoring tools like
dataDisplay or VegaWeb have been extensively
used since year 2001.

• DAQ has shown to be
• modular (lego pieces with standard connections
  between them)
• reliable and quite easy to use (and to restart)
• flexible and evolutive
• latency minimized

• Beyond DAQ
• Useful data streams (raw data, trend data, 50Hz
  data, processed data, ) are under definition
• Online analysis has started