Details of the viewer

(See the general overview section for specifics on how to run the viewer.)

Structure of the viewer

All you really need to know is that it's a ROOT style GUI, and as such, it's pretty easy to navigate...

...but look for a tech note sometime soon that I will write and post to docDB.

Using the viewer


The viewer looks something like this:

In the top left, you will see three tabs labeled "Histograms", "Comparison", and "WatchList". The "Histograms" tab will display all of the histograms available for viewing. If you are a shifter, the folder marked "Shift" is what you want to focus your attention on. When problems arise, you can navigate your way through the other folders to determine the the nature and extent of the problem. The "Comparison" tab will allow you to compare the current histogram to a variety of previous histograms (more details in the next section.) The "WatchList" tab will allow you to add specific hardware to a list of hardware for which specific histograms will be made (more details below.)

Near the top left, you will see several navigation buttons. There is a forward and a back button to allow you to navigate through the history of histograms that you have been viewing. The history keeps track of up to the last 16 histograms viewed and functions the same way as an internet browser's history. In addition to these buttons, there are pause, play, and refresh buttons which function as expected (pause will turn off the viewers auto update, play will turn it back on, etc.) The last button will print the current histogram being displayed to a .png file titled with the histogram name.

The main central portion (obviously) displays the current histogram and is a typical ROOT canvas, meaning you can do things like zoom in and set Logx (although you may want to pause the viewer before doing this, otherwise the auto update will frustratingly un-zoom your plot while you are looking at it.) Single-clicking on any bin in the current histogram being displayed will display information about that bin (bin #, content) in the top information bar next to the browsing buttons. Most of the 2D detector view histograms also have a "drill-down" feature enabled. That is, by double-clicking on a bin in one of these plots, another histogram will be displayed. For example, in the DCMHitMap plot, if you double-click on a specific DCM, then the detailed plot by pixel for the selected DCM will be displayed (these histograms can also be accessed from the list of histograms in the "Histograms" tab.)

The bottom two boxes contain additional text information about the histogram being displayed. In the smaller of the two boxes, you will find a more detailed description of what the histogram contains as well as information about how it is binned and how often it updates. The longer, skinny box displays errors and other messages from the viewer.

Using the Comparison tab

Begin by selecting the histogram you want to see from the "Histograms" tab. Then select the "Comparison" tab to display the comparison options.

The "Comparison" tab looks like this:

First select the source for the reference histogram by selecting either selecting "Reference" and typing in a specific reference (filename.root to use a file on disk, SHMhandle.shm to use an existing shared memory block) or selecting "Recent" and choosing the desired look back number (i.e. - how far back in the list of recent histograms.) Next, choose the comparison method and the normalization method (the reference histogram is always normalized to the current histogram.) Finally, when you have selected the options you want, click the "Apply Options" button to see your comparison plot. When you press the "Apply Options" button, the viewer is automatically paused. Choosing "None" from the "Compare to..." box and pressing "Apply Options" again will un-pause the viewer (or you could just un-pause it yourself...)

Using the WatchList tab

The WatchList tab will allow you to tell the producer to begin making histograms for a set of hardware that you specify. The plots that are made reflect information not obtainable from any of the regular OnMon plots. For example, you can get hit count information about any pixel by looking at the appropriate HitCount map by DCM, but you can not get time or ADC information about a specific pixel or FEB (since that information is mixed together with all of the other pixels from the same DCM in the TQPlots.) Therefore, the WatchList plots are a 1D hit time plot, a 1D ADC plot, and a 2D TQPlot for the selected hardware.

The layout of the WatchList tab looks like this:

In the top box labeled "Chose Hardware" select the hardware you would like to add to the WatchList. The pull down menus are automatically populated with numbers appropriate to the detector type as specified when launching the viewer (they do NOT reflect the hardware currently installed.) Note that "ALL" is one of the options, such that choosing "02-ALL-23-ALL" will make plots for every pixel on FEB 23 in each DCM on di-block 02. Once you press "Add", a message will be sent to the producer to add the selected hardware to the WatchList and begin making plots. Flipping back to the histogram browser tab, you should be able to see the new WatchList plots right away. Note that the maximum number of items that can be on the WatchList at any given time is 64 (which includes the items marked as removed - see below.)

Items currently on the WatchList are displayed in the "Current WatchList" box below the "Chose Hardware" box. From this box, you can remove items from the current list by selecting them (multi-selection is enabled) and pressing the "Remove" button. When items are removed, they will disappear from the current list and the producer will stop filling the associated histograms. BUT the histograms will continue to exist and can be seen in the histogram browser until the end of the current subrun. Only after the end of the subrun, and after all histograms that the producer has have been written to a root file, will any WatchList items and histograms marked as removed be permanently deleted. The viewer's histogram browser does not refresh when the producer deletes watchlist histograms, so it is possible to select a histogram in the browser that doesn't exist anymore. In this case, you will get an error message (in the message box) saying that the viewer can't find the requested histogram. Feel free to press the "Refresh Histogram List" button in the histogram browser tab to request a copy of the current histogram list from the producer.