Use Case:  Set FSS Aperture Field Diaphragm

Description:  Set the Field Stabilization Aperture Field Diaphragm to the requested aperture diameter.
This action is invoked during normal operation to minimize the sky background effects on the servo-loop..

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

Priority: Major

Performance: TBD

Frequency: At any time

Package Assignment:  Field Stabilization Subsystem.

Preconditions: 

• FSS is ONLINE

Basic Course: 

• Send command SETAFD <diameter> to set the FSS Aperture Field Diaphragm to given diameter
  Exception Course: Command failed
• ATCS sends command to FSS sub-system

  Interface: STRAP

  Exception Course: Command failed
• ATCS returns OK reply

Exception Course: Command failed

• ATCS returns ERROR reply
  Postcondition: FSS Aperture Field Diaphragm not moved

Postconditions: 

• FSS Aperture Field Diaphragm at given diameter

Issues to be Determined or Resolved:  FSS Aperture Field Diaphragm diameter range

Notes:

Last modified: Thu Jun 28 13:18:52 UTC 2001