High-precision DAQ system

* Overview

* Hw_script
* Preload
* Musplay
* Mixer
* Cdman
* Tgt-edif
* fx2_programmer
* Software Radio
* LIGO viewer
* DAQ system

* Status
* CVS
* Download

* About me

The data acqusition system pictured above can acquire data with 24-bit resolution at 50 kS/s and output high precision (16 and 20 bit) voltages. It was created with mostly Open Source software, with the exception of two components: Xilinx WebKit and Digilent Adept, both of which are freely available, but closed source.

Why not use ready-made commercial cards ?

• There is often a large lag between release of new ADCs and DACs from manufacturers and when they become available in commercial cards.
• High end cards are usually very expensive.
• There is usually no access to FPGA and no way to enforce particular timing regimes (i.e. you cannot sync your digital circuits to a GPS module or other custom clock)
• A data sheet for a TI or Analog ADC has exhaustive documation of device performance. A commercial ADC card often says that it is "16-bit" and, maybe, provides absolute maximum voltages.
• There is a disturbing tendency of many companies to force their custom software on users, which interferes with application in real-life situations.

Advantages of custom DAQ system

• You have complete control over FPGA programming:
  • Input and use custom clocks
  • Create and output custom clocks, use them to annotate acquired samples.
  • Implement control circuits directly in FPGA.
• Use Ethernet to transfer data to main analysis computer.
• Use ready made evaluation boards or make your own for latest ADC/DAC chips from any manufacturer.

Features of this daq system

• Accepts 24-bit 50 kS/s TI ADC modules.
• Accepts 16 and 20 bit TI DAC modules.
• Interfaces to main data acquisition computer via 100 Mbit ethernet cable.
• Design made mostly with Open Source software, with the exception of FPGA programming tools (Xilinx Webkit and Digilent Adept).
• Part cost less than $1000 for a single unit.

Papers using this daq system

• A high precision, compact electromechanical ground rotation sensor, V.Dergachev, R.DeSalvo, M.Asador, A.Bhawal, P.Gong, C.Kim, A.Lottarini, Y.Minenkov, C.Murphy, A.O'Toole, F.E.Pena Arellano, A.V.Rodionov, M.Shaner, E.Sobacchi, RSI 85, 054502 2014)
• Design and Initial Characterization of a Compact, Ultra High Vacuum Compatible, Low Frequency, Tilt Accelerometer, A. O'Toole, F.E.Pena Arellano, A.V.Rodionov, M.Shaner, E.Sobacchi, V.Dergachev, R.DeSalvo, M.Asadoor, A.Bhawal, P.Gong, C.Kim, A.Lottarini, Y.Minenkov, C.Murphy, accepted to RSI.
• Wiener filtering with a seismic underground array at the Sanford Underground Research Facility, Michael Coughlin, Jan Harms, Nelson Christensen, Vladimir Dergachev, Riccardo DeSalvo, Shivaraj Kandhasamy, Vuk Mandic

Documentation

• Manual (PDF)
• Assembly diagrams:
  • Carrier board front
  • Carrier board back
  • Drilling template for bottom panel
  • Power supply board front
• Source code
  • DAQ daemon and user interface
  • Carrier board description file, compiled Gerber files
  • Power supply description file, compiled Gerber files
  • Library used
  • Description of PCB_TCL language these files are written in.
  • Bitstream for FPGA, v5.0
  • Bitstream for FPGA, v6.0
• Vendor documentation:
  • Digilent Spartan 1600 page.
  • Digilent user manual, schematics.
  • TI docs:
    • ADS1278 webpage, eval module webpage
    • ADS1282 webpage, eval module webpage
    • DAC8734 webpage, eval module webpage
    • DAC1220 webpage, eval module webpage
• Source files for board design and manual