These procedures define a variety of logical names and symbols (VMS) or environment variables and aliases (UNIX)

Other permissions may be necessary depending on what you need to do. See New NSTX User Setup for more detail.

How do I know what data exist?

• Navigate through an MDSplus tree using Traverser. Descriptions of signals should be in a :LABEL subnode.

• Scan or select "Find in Page..." from your browser in the NSTX Signals and Labels page,

• Generate advanced searches with the MDSplus Tree Search Tool.

• Some of the most commonly-viewed signals can be displayed from the NSTX MDSplus Plotting Tool. Select "Tag Names" for "Plot Labels" to see the tag name.

• To find what shot numbers are on-line, especially non-standard ones like test shots (4 digits) and calibration shots (7-digits), on VMS, type HELP MDIR.

  Example for 7-digit shot numbers:

     EUROPA$ mdir 1%%%%%%/tree=passivespec
  
                 Filename                     Directory
     PASSIVESPEC_1010001.DATAFILE;1         NSTX$ARC$:[PASSIVESPEC.101.00]
     PASSIVESPEC_1013001.DATAFILE;4         NSTX$ARC$:[PASSIVESPEC.101.30]
     PASSIVESPEC_1013002.DATAFILE;2         NSTX$ARC$:[PASSIVESPEC.101.30]
  	     

• In addition to the data in MDSplus trees, summary data may be found in some of the databases available. DbAccess may be run from IDL on Linux. (see Dana Mastrovito or Bill Davis for details and extensions,)

How do I look at data?

• The most efficient tool is Scope. Commonly-used scope input files can be found on Linux in the /p/nstxusr1/util/scopes directory. The PAD utility helps you build new scope input files. First time users should ask a colleague or a programmer for assistance in building their own scope files. Scope does not do overlays or display in color.

• From the Web you can use the NSTX MDSplus Plotting Tools.

• An IDL widget may be used called MDSW. Type "mdsw" from within IDL and use the help menu.

• IDL programmers can write their own code for access to NSTX data in MDSplus. See http://NSTX.pppl.gov/nstx/Software/IDL/idl.html for information on IDL at PPPL.

• With Fortran, from UNIX
  (See Gretchen Zimmer)

• MDSplus access routines are also available from C, LabView and VisualBasic.

• Traverser. can show you raw numbers imbedded in TDI, but arrays are truncated.

Do I have to restore data?

No. A design goal is to have all data on disk, at least for the last three years. Note that you may write results to MDSplus trees (even years after the shot), and not worry about your own file quotas.

How do I find out about how the machine was running for a certain shot?

• The NSTX Electronic Logbook is available on the web.

  You may also run the NSTX logbook from IDL (using X-windows) on Birch, Europa, or KEES. (PPPL VMS computers). Type "setup logbook" (without quotes) at the DCL prompt and follow the instructions. On Linux, if you have done a "module load mdsplus/nstx" (and other things necessary for New-user Setup):

     % IDL
     IDL> syb_entry
  

  An on-line Logbook manual is available, as are PDF and Microsoft Word versions. Errors and questions should be directed to Stan Kaye.

• Some of the most commonly-viewed signals can be displayed for a given shot from the NSTX MDSplus Plotting Tool.

• Various databases provide summary information in tables. DbAccess, run on Linux, conveniently shows NSTX database tables and their contents. (see Dana Mastrovito for more information.)

• Some database parameters of general interest may be plotted on VMS by running surveyw from IDL, and clicking through the dates:

     EUROPA$ setup idl
     EUROPA$ setup logbook
     EUROPA$ IDL
     IDL> surveyw
  

• You may wish to use the NSTX MDSplus Shot Search Tool, or the NSTX EFIT Database Searching Tool, to display shots with a certain range for a signal.

What if I want to add my own comments about a shot?

You will need a "write-access" priviledge. You may want to create your own "topic." See dbadmin@pppl.gov for assistance.

For a particular diagnostic and a range of shots, how do I find out which shots have data or have valid data?

You may use the NSTX MDSplus Shot Search Tool or one of the database tools.

What were the first and last shots for a run day? for an XP?

The software WebTools page provides indices for XPs and XMPs.

What is MDSplus? What are these "tags" and "nodes"?

[From the MIT MDSplus home page, February 1999]

"MDSplus is a data acquisition and analysis system developed jointly by
   MIT Plasma Science and Fusion Center, Cambridge,MA
   Los Alamos National Laboratory, Los Alamos, NM
   Instituto Gas Ionizzati, Padova, Italy "

"MDSplus provides a set of tools for performing data acquisition and analysis for pulsed experiments. It is designed to keep all experimental data, analysis results, experiment configuration and setup information together in an organized fashion. The data for each pulse of the experiment is stored in a hierarchical tree structure much like a file system. Each item of data (i.e. the data from a digitizer channel, a setup parameter, a comment) is stored in a node in the tree. [emphasis added] This organization enables the users to keep track of large numbers of pieces of information. Currently the tree describing the Alcator C-MOD experiment has nearly 44,000 nodes containing information in over 1400 "directories".

Each item of data can be any of several supported data types. These include elemental data types such as integer, floating point, text, or some more complex data types such as signals, devices, actions."
[End of quoted material.]

A tag is a shorthand name for the full tree path from the top of a (sub)tree to a given node. A node has just one name, but may have many different tags (tagnames). For example, one of the nodes that holds the NSTX corrected plasma current, in the Engineering tree, is PLASMA_CUR1. The full path to that node is \ENGINEERING::TOP.EPICS.FCPC.DIGITIZERS:PLASMA_CUR1. This full path could be used to retrieve the data, timing and units. The tag for the same node is \ENGINEERING::PC_PLASMA_CUR_1 It could be used wherever the full path could be used.

How do I find the full path of an MDSplus tag?

You can use the TDI function GETNCI, for \IP, e.g.,:

     IDL> print,MDSVALUE('_t=getnci("IP","fullpath","ANY")')

     IDL> print,fullmdspath('\ip')

How do I make my own Scope layout files?

1. It is best to copy a scope file from a friend, or one of the commonly-used scope input files found on VMS in the NSTX$:[UTIL.CONFIG] directory or on Unix in /p/nstxusr1/util/scopes/.

2. Read about the Copy mode in the Scope documentation (in a scope, select the Copy button at the bottom, click on a graph with the left mouse button, click with the middle mouse button in the window you want the plot).

3. Change the numbers of windows by selecting "Window" under the Customize menu.

4. Hold the right mouse button down over a plot to see options for changing scales, signals, etc.

The scope input files can be edited with a text editor, but there are non-obvious relationships between some values, so this is not recommended.

How do I add my favorite printer to the Scope menu?

1. For Scopes run on VMS:

   The printer list comes from the system logical name DECW$PRINTER_FORMAT_PS. You could define your own by putting something like the following in your login.com file:

        $ DEFINE DECW$PRINTER_FORMAT_PS "NSTX_XN4525,NSTX_T860DP,B143"
   

2. For Scopes run on Unix:

   The printer must be added to the file /usr/pppl/nstx/mdsplus/local/scope_printers. Send your request to nstx_sw_dev@pppl.gov.

What "canned" plotting, data display and other IDL routines are there?

• An IDL widget called MDSW. Type "mdsw" from within IDL and use the help menu. Available signals are listed when "Show Signal Menu" is selected from the Special menu. Searches using wild cards may be made by entering a string into the Filter field, and hitting Enter.

• FAS - Fusion Analysis Software, is a full-featured plotting utility that understands NSTX MDSplus data. A hardcopy of the FAS manual is available from Dave Gates. FAS (and other MDSplus-access codes) can be used for accessing MDSplus data at other sites.
• There is web-based help on user-written IDL routines used at PPPL, including code for access to NSTX data in MDSplus.

Is there a way I can let other physicists know about my tags and how to look at my data without having to tell everyone separately?

• If you place descriptions of signals in a :LABEL subnode, it will show up in the NSTX Signals and Labels page within a weeks time, or if you send email to Gretchen Zimmer.

• You should copy an appropriately-named scope file to the NSTX$:[UTIL.CONFIG] directory on VMS.

Can I see the shotclock count down from my office?

On the Linux Cluster, say an nstxpool computer:

	module load nstx/epics
	nstxclock

How can I make a test tree for MDSplus?

See How to Make a Private MDSplus tree

How do I find the files that constitute an MDSplus tree?

See How to find the files of an MDSplus Tree

Written by Phyllis Roney
Edited 03-Jan-2008 by: Bill Davis