MDSplus Action Nodes

Data analysis with IDL can be scheduled through MDSplus Action nodes. An example of creating an Action node to run an IDL script during an NSTX-U Shot Cycle is provided on this page.

  1. The WRITETEST action node was added by opening the cameras model tree (shot -1) in Edit mode in Traverser, selecting the TEST node, pulling down the Edit menu, and selecting "Add Node". Name the node and click the "action" radio button. Click OK. (Depending on your permissions, you may need to open the tree on the MDSplus server, which is skylark at PPPL.)

    1. Select the Action Node (WRITETEST in this example), right click and select "Modify Data".
    2. In the Modify Data_popup, select "Action" from the pull down menu.
    3. Then select "Sequential" from the pull down menu that appears below it.
    4. In the menu to the right of the "Sequential" menu, named "Undefined" select "Expression."
    5. Fill in the fields as appropriate.

    Note that you must put "localhost" as the second argument in the SUBMIT command if you want the script to run on skylark. Be sure to make /p/tdi/ActionIDL/actiontest.sh executable. (chmod a+x actiontest.sh)

  3. Since this code will run on skylark, it must use routines accessible from skylark, like under /p/tdi. Be sure to use the full path to IDL on skylark.

  4. Make sure the log file being written to is writeable, e.g.

  5. If you haven't assured that your code will run after the necessary data is available for a shot, your code should try to open the MDSplus tree for that shot, pause for 10 seconds, try again, etc., until successful. A similar loop should be used for reading the desired signal(s).
  6. After the shot, you can look for messages and errors by: 
    tail -300 /usr/local/mdsplus_pppl/logs/nstx_mon_server/access