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DaqLinux at the Edwards Accelerator Laboratory

Ohio University Edwards Accelerator Laboratory, a 4.5 Million Volt tandem accelerator.
Ohio University Edwards Accelerator Laboratory, a 4.5 Million Volt tandem accelerator.

DaqLinux User GuideControl & Computer Startup Instructions

DAQ is a data acquisition software suite that has been developed at the Edwards Accelerator Laboratory located at Ohio University. This software has been under continuous development since the early 1990s. The design concepts for DAQ were also used earlier on in-house built computers used at the laboratory dating back to the mid 1970s when similar code was developed for data acquisition. These earlier codes were written in assembler language and were used until the advent of the PC when the codes were rewritten in C and ported to the less expensive high-performance computers that became available in the 1990s.

The initial rewritten code was ported to DOS then ported to Windows 98 and used extensively throughout the 1990s. In the latter 1990s the DAQ code was again rewritten and ported to Linux to take advantage of this multiuser, multitasking virtual memory environment. The current state of DAQ is a suite of software running on Linux systems.

The design goal of DAQ is to provide a flexible data acquisition and experiment control environment that is adaptable to a multitude of types of experiments taking place in a nuclear physics research facility.

About DaqLinux

DaqLinux is a suite of programs that allows the user to acquire interrupt driven high speed data from devices commonly used in the nuclear physics laboratory. Current commonly available PC hardware will allow data rates of well in excess of 100 kHz with dead times less than 10% through the interrupt driven device driver channel. DAQ has been used with Camac, Fastbus, VME and in-house built hardware. The interface is modularized and should easily be modified for other types of data paths.

The DAQ device driver buffers the data then passes the data to the event handling fork of DAQ where a user supplied (or canned commonly used) program processes the data. The data can histogram 1 or 2 parameter arrays, save event mode data to files, make event by event decisions on the data then route data as a function of routing decisions, etc. A set of functions supplied by DAQ make these operations simple by calling supplied function routines to interface to the data analysis and control side of DAQ.

DAQ has a set of commands used to manipulate and view the data online. Data can be saved, recalled, manipulated, viewed and analyzed online. DAQ also contains a DAQ command language interpreter that allows the user to write experiment setup, analysis and control routines. This allows DAQ to be customized for many different types of experiments. Once an experiment is defined using the DAQ command language, the complete experiment may be restarted automatically and a complex automatic experiment control system may be started. The DAQ  command interpreter can interface directly to hardware devices to control and monitor the experiment operation. It has access to all the data in the histogram files for online data analysis and manipulation. The user also has access to shell commands while within the DAQ environment.

What's New

DaqLinux has been updated to allow a distributed networked control and data storage environment. This new system is called Distributed Data AcQusition (DDAQ) and is being used where the experiment detectors each have a dedicated DAQ computer but are networked to have their control and data storage originate at a single master computer.

DaqLinux is currently being used for data acquisition and control on systems running Scientific Linux SL4.4. The NMR and Accelerator controls are using a RedHat 9.0 system with a National Instruments GPIB controller. The primary data acquisition computers are running Scientific Linux SL3.0.9 and Red Hat Linux 8.0. Another data acquisition system running RedHat 5.2 is connected to systems serving the small target room. Other systems are running connected to a camac crate controller in the control room and the undergraduate lab.

Accelerator Control and Monitor Computer Startup Instructions

  • Make sure that the firewall is up and running. If not, reboot the firewall and wait until it is up.
  • Reboot the computers at the console ( and
  • While the computers are rebooting, power cycle the 3 HP34980A located 1) in the control room over the radiation monitor 2) in the small target on the overhead cable tray 3) at the sputter source if possible.
  • After both computers are running login to control1 user "carter" using the usual lab default password.
  • Issue the command "startx" on computer
  • Click on the "start_tandem" icon on the desktop. This should start all of the control and monitoring applications.
  • If the monitoring system still isn't working properly, the previously saved data may be corrupt. You can archive and clear the previously saved logging data by clicking on the "Carefull+" button and selecting the "ClearDeviceLogs" then again click on the "Carefull+" button and select "RestartAll". If this doesn't restore operation there may be a network problem or may need attention.