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Data acquisition at GEO600

Data acquisition at GEO600. Martin Hewitson. DCU (thot). east. DCU (pandora). north. Schematic overview (Ruthe). coch. 32f/64s chans 1 MB/s. DCU (alchemist). central. Data collector. To Hannover (< 1 MB/s). vDCU (control). Raw data server. 1000us 5 kB/s.

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Data acquisition at GEO600

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  1. Data acquisition at GEO600 Martin Hewitson

  2. DCU (thot) east DCU (pandora) north Schematic overview (Ruthe) coch 32f/64s chans 1 MB/s DCU (alchemist) central Data collector To Hannover (< 1 MB/s) vDCU (control) Raw data server 1000us 5 kB/s f = fast (16 kHz) S = slow (512 Hz) Us = ultra-slow (1 Hz) 16f 500 kB/s 16f 500 kB/s GEO meeting Sept 2004

  3. DCU Fast channels Slow channels GEO meeting Sept 2004

  4. Data collecting software Writes data to disk in proprietary format Uses GEO directory structure Raw data server Accessible from Ruthe 1 sec latency On Coch… GEO meeting Sept 2004

  5. Schematic overview (Hannover) bute client frame maker h(t) maker fserv 9000 From Ruthe (< 1 MB/s) RAID array (3 TB) hour trend maker day trend maker client fserv 9008 Charlie (Archival) GEO meeting Sept 2004

  6. A summary of file types • Raw data files (1 second duration) • fs <= 16384 Hz • One file per DCU per second • Frame files (1 minute duration) • fs <= 16384 Hz • 60 frames per file, one second per frame • All channels in one file • + calibration information • Hour trends files (1 hour duration) • fs = 1 Hz • 60 frames per file, 60 seconds/samples per frame • Min, max, av • Day trend files (1 day duration) • fs = 1/60 Hz • 24 frames per file, 60 minutes/samples per frame • Min, max, av GEO meeting Sept 2004

  7. Current DAQ system - summary • Commercial solution (mostly) • Has evolved into quite a stable solution • 99% reliability • improvements mostly due to software • Some problems remain • Easily damaged input stage • Sometimes high level of cross-talk is observed • Some parts are obsolete • Main drawbacks • Costly repairs and replacement parts • No user-serviceable parts GEO meeting Sept 2004

  8. Moving forward • Continue with the current system? • Need to repair ADC boards once per year • Spare processor boards no longer available • Problems still exist with signal sizes and channel overload protection • This needs more investigation • Cross-talk is difficult to predict and control • Move to a new DAQ system GEO meeting Sept 2004

  9. A new DAQ system • Aims: • Replace existing system with something we can control • More exactly meet the needs of GEO • Make something cheap (comparatively), expandable and versatile • A flexible system that can also be used in lab environments • Extends the current software model of parallel data streams GEO meeting Sept 2004

  10. General approach • Make a modular system • Each channel is an independent module • Each module collects data and sends it over ethernet • Modules can be placed anywhere (near signal source) • Cost per module ~€300 + infrastructure GEO meeting Sept 2004

  11. System overview GEO meeting Sept 2004

  12. A channel module • Single channel board designed to fit into its own enclosure • Each module connects directly to a data collecting computer via TCP/IP GEO meeting Sept 2004

  13. Advantages over current system • Each channel is independent of all the others • Cross-talk is minimised • Effect of failures is minimised • Only the required number of channels is used • Individual channels can have independent acquisition rates • Individual channels are easy to repair/replace • Channels can be placed close to signal source • Reduces pick-up of noise GEO meeting Sept 2004

  14. Open questions • What is the required operational time of the current DAQs? • Should we be looking beyond GEO? • GEOHF needs • Are we happy to continue with the (costly) repairs? • Should we move to a new DAQs? • Manpower? GEO meeting Sept 2004

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