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Next: What To Do When Up: Data Acquisition Previous: Setting Data Acquisition (CODA

Taking data

The DAQ states and transitions which can be executed by pressing the appropriate buttons in the Run Control GUI are shown graphically in Fig. 2.43. Edit the file /home/cdaq/$DAQROOT/coda2/cdaq.flags (moller.flags for Møller running) to set/change flags. The keywords have to be on one line with no spaces inbetween. Don't forget to save the file. The values are downloaded at \fbox{Prestart}. The following keywords can be specified:
sparse: Turns on sparsification
buf: Turn on buffered mode
nped=: Number of pedestals to be taken at beginning of run
Trigger prescale factors:
ps1=: HMS single
ps2=: SOS single
ps3=: Coincidence

Figure 2.43: State Diagram for the DAQ System, controlled by the Run Control GUI
\begin{figure}\begin{center}
\framebox{
\psfig{figure=coda_scheme.eps,height=8cm}} \end{center}\end{figure}

To start a data taking run, click the \fbox{Prestart} button. After a few seconds a \fbox{Go} button should appear. Click this button.

After \fbox{Go} is pressed, a ``Run Info'' form will pop up. This form should be updated to reflect the running conditions of the run about to be started. The form is filled with default values, but may be overwritten with the values from the last run by clicking on the \fbox{Last Run} button. The current values may also be save as default values if several runs with similar conditions are expected. When the \fbox{OK} button is clicked, the values held in the form will be written to the data file and the run will be started.

Please write sensible comments in the ``Comments'' field. The first line of the comments will appear in the title of the electronic log book entry made for the run, so it should be reasonable descriptive.

To modify the layout of this form, edit the file ~/$DAQROOT/coda2/runparms.default, consulting an expert if necessary.

To pause/resume a run, use the \fbox{Pause}/\fbox{Go} buttons on the pause GUI.

A run will end if either you click the \fbox{End} button or the event limit or the data limit (whichever is first) is reached. Event and data limit can be specified in the Run Control GUI. Enter a number in the appropropriate field and hit $<$return$>$. Our CODA system has been configured to allow runs with sizes greater than 2GByte in size. This is done by automatically closing the data file and opening a new file. Thus a long run will be split into several segments. The run filenames have the form e93038_XXXXX.log.N, where N is the segment number, starting with 0.


next up previous contents
Next: What To Do When Up: Data Acquisition Previous: Setting Data Acquisition (CODA
Hall-C Staff
2002-11-04