Getting Started With the Online Monitor

First think to know this code is written and maintained by Marcelo Munhoz so send comments/questions/suggestions to him and or the SVT soft list. The code lives in /star/svt/online/StRoot/StSvtQAMaker. This code is designed to let (hopefully) non-experts look at the raw SVT data. Its pretty much graphics driven which means that if you are running off site it can be pretty slow as you have to fight your way through the BNL firewalls. Its not the codes fault so just be patient.

So onto how to use it type the following commands on a rcas machine at BNL:

cd /star/svt/online

starnew - Gets you into the "new" version of the STAR library

root4star

.x SvtDataViewer.C

Two windows should pop up. The one labeled "On Line Monitor" is your control panel. Its shown in Fig. 1 below. To open a data file click on "control" and then open data file, also shown in Fig. 1 below. Mostly you can ignore what gets printed to the terminal window, unless you want to report an error then its useful to let Marcelo know what was printed.

Fig 1. The Main control window. Opening a data file

Click your way to the data file you want in the window that pops up. The first event of this file will also be read in. You now need to "inform" the code what kind of data you are looking at. You can pick between " zero-suppressed, non-zero-supressed and Sequence adjusted". Mostly you will be looking at zero-supressed data so this is the default. Zero Supressed is how the raw data gets written out. Only for debugging purposes is the data written out non-zero supressed. These options lie in the "Data" menu. Shown in Fig 2.

Fig 2. Selecting the data type

Most of the SVT data files are in

/star/data03/daq/svt/2001/Bon
                          Boff
                          Injector
                          NoiseTests
                          Pedestal
                          raw

in sub-directories of their run numbers

Also shown in the window is a graphic display of the SVT barrels and ladder. Highlighted in red is the ladder for which the data currently being displayed and the Hybrid of that ladder. By clicking in the grey buttons you can select different ladders and hybrids to view. In Fig 2 Ladder 1 hybrid 1 Wafer 1 has been selected.

If you want to look at pedestal data you need to select the "Get Pedestal fron DAQ file" option shown in Fig 3.

Fig 3. Reading in a pedestal file

Most of the other menu options are (hopefully) self descriptive so click away. Some of the most useful options are:

view -> ladder - Display all the hybrids for the selected ladder at one time
view -> Projection in ** axis - Allows you to project various slices of a 2-D plot onto the x or y axis.
Single Event -> Raw ADC vs Time - Allows you to view a 2-D plot of a hybrid and see the hits in timebucket vs anode space.
Edit -> Set max/min etc - Allows you to re-bin the histograms if the default scale is crazy.
Canvas (not the control window) Edit-> Save As... - Allows you to save to gif or postscript the plot you are looking at.
Control -> Get Event - Gets the next event.
Data -> Sequence Adjusted - Allows you to look at the after the offline sequence adjusting is run. Hopefully you see the noise vanish and the hits remain.

Fig 4. Example raw ADC and ADC - Andoe vs Time plots

Now you are set to play. Please report to us anything you think is missing or unclear. Also this code is still in developement so if you make it crash please report to us how you did it, sigh, and start again. Its pretty stable but there are some collections of clickings that are not a good idea.

Helen Caines

Last modified: Thu Aug 16 12:21:06 EDT 2001