Purpose

This page is meant for support astronomers only

Procedure

1. Attempt to initialize the stage one more time only using the XNIRSPEC/Engineer/Motors/Init menu item.
2. Check the status of the switches using the XNIRSPEC/Engineer/Motors/Read Switches menu item.
3. If no switches are set for the filter wheel in question, this indicates that the stage is not centered on a filter. Follow these steps to recenter:
   • Login to waimea as user nirspec.
   • Issue the command cdkw to go to the NIRSPEC keyword software directory.
   • Issue the command

     source fil1.csh

     (if filter wheel 1 is failing, else use fil2.csh). This script will move the stage 10,000 motor steps in increments of 200 and print out the status of the switches after each move. The status will be 15 as long as the wheel is between position. Interrupt the script (using Ctrl-C) immediately if the value changes from 15 to another value. If the script completes 10000 motor steps without ever seeing a switch, then a significant number of motor steps must have been lost (or the switch is failing). In this case, repeat the script once more to attempt to find the switch. If it fails again, then it is unlikely to work at all --- the wheel is probably stuck and/or the motor is burned out.
   • Check the status of the switches using the XNIRSPEC/Engineer/Motors/Read Switches menu item. If the position switch is set, then you were able to stop the mechanism in a centered position --- proceed to the next step. If not, you must backtrack to locate the switch position by typing this command:

     source rfil1.csh

     (or rfil2.csh as appropriate). Note that this script prints out both the status of the filter wheel switches and the status of the slit switches. Again, hit Ctrl-C if and when the fil1sw value changes. Re-check the switch settings as described above and, if needed, run fil1.csh to go back in the other direction. Repeat as needed until you are able to catch the position switch 'on'.
4. On the Read Switches menu, check whether the Pri Init or Sec Init light is 'on':
   • If Pri Init is on, you are a lucky soul, because you found the primary initialization position for this wheel. Consult this table to determine which filter you are at. Read the corresponding motor step position, and enter this command to initialize the wheel manually:

     m filMinitloc=N

     where M is the filter wheel number (1 or 2) and N is the number of motor steps from the table. Example: if you are on filter wheel 1 and have hit the primary init switch, then you've found M-wide at 90,000 motor steps.
   • If Sec Init is on, you are an equally lucky soul, because you found the secondary initialization position for this wheel. Consult this table to determine which filter you are at. Read the corresponding motor step position, and enter this command to initialize the wheel manually:

     m filMinitloc=N

     where M is the filter wheel number (1 or 2) and N is the number of motor steps from the table.
   • If neither the Pri Init nor the Sec Init light is 'on', then we still can't determine our location unambiguously. In this case, continue running fil1.csh (or fil2.csh) until you hit the next position switch, then again use Read Switches to check for Pri Init or Sec Init. Continue as needed until you hit one or the other.
5. Once you've located a primary or secondary initialization switch and used the filMinitloc keyword to define position, the XNIRSPEC window should properly reflect the current position. This means that you can use the Echelle Format Simulator window to manipulate the instrument as long as you set the requested filter to whatever is currently in the flaky wheel.
6. If you are brave, you can try moving to an adjacent filter using the filter selector buttons on XNIRSPEC. But beware --- if the move fails, you'll need to start again looking for position switches and initialization switches!