INSTRUCTIONS TO RECOVER FROM LIMITS

Creation -- 11/06/02 -- EF

Update -- 11/07/02 -- EF

CAUTION: ONLY for experienced observers! If you think you need a recovery and it is your first time or it has been a while since you used FAST, PLEASE consult with staff first!

You may reach a limit in one of the FAST motors (focus or sky/comp) because of a software or hardware fault. If you have any doubts about the location of the failure, please consult with staff first.

  • First, exit the rtshell using the "bye" command. Then, go into the chamber and make sure the connector bank on the West side of FAST (with the telescope at zenith) for the focus and sky/comp motors is accessible (each connector is appropriately labeled).

  • Unplug the power cord for the motors on the power strip attached to the bottom of the cell to the South, if the telescope is at zenith. The power cord is labeled "motors."

  • Find the jumper cable labeled "limit finder", usually in the cabinet at the computer room. The jumper is also used at the 1.2m, so you may need to ask staff for assistance in finding it. Unplug the signal cable for the motor that reached a limit (focus or sky/comp) from its connector, plug the male end of the jumper in its place, and plug the cable into the female end of the jumper. Make sure you have a good connection at either end.

  • Restart the rtshell using the "gofast" command. The system should start, and the motor that had reached a limit should move away from it to a reasonable place.

    • Exit the rtshell again, as above. Follow the sequence above, this time removing the jumper cable. Once that is done, you should be able to restart the rtshell and proceed with observations.