From time to time the LRIS shutter tends to get stuck in a partially open state. Follow these steps to cycle the shutter and hopefully free it up:

Keyword Control

This is the preferred method for opening and closing the shutter.
  1. Open a lrisserver window.
  2. Perform a close-open-close shutter sequence by typing the following command: 
      cycle_shutter
  3. The script executes three keyword commands. It is acceptable for the first to fail, but the second two should succeed.

Low-level Control

Use this procedure only if you cannot move shutter using keywords.
  1. Open a CCD crate session. From lrisserver type: 
    telnet tserver4 3010
  2. Press <Enter> to get the VME prompt (->).
  3. Perform a close-open-close shutter sequence by typing the following commands: 
      ub_com 0, "CSH"
  ub_com 0, "OSH"
  ub_com 0, "CSH"