Use Case:  Stop Telescope Motion

Description:  This function is used to make a "soft stop" of the telescope moving under position control, that is during presetting or tracking. The actual position when the command is sent is recorded. Then tracking is switched off, if active, the moving axes are brought to a standstill, and then moved to the recorded position. The telescope is kept halted, but under position control, on this position.

Role(s)/Actor(s): 
Primary: Operator, Maintenance

Priority: Critical

Performance: 1 second

Frequency: At any time

Package Assignment:  Presetting.

Preconditions:

• Telescope axes are ONLINE

• Send command STOP to Stop telescope motion
  Exception Course: Command failed
  
• ATCS sends stop command to the telescope axes

  by Stop Tracking (TRK/STOP)

  Exception Course: Command failed
  
• ATCS returns final OK reply

Exception Course: Command failed

• ATCS returns ERROR reply

Postconditions:

• Tracking Axes stopped
• Brakes remain released & Control Loops remain closed
• State ONLINE substate IDLE

Issues to be Determined or Resolved:None

Notes:Sending a Stop followed by a Preset identical to the former one is the normal way to pause and restart the telescope.

Last modified: Thu Jun 28 13:52:06 UTC 2001