Use Case:  Open Enclosure

Description:  Deflate seals and open telescope enclosure

Role(s)/Actor(s): 
Primary: Operator, Maintenance
Secondary: Enclosure, AC, ASM

Priority: Critical

Performance: 2 minutes

Frequency: Once per day at beginning of night. Or at any time when required for maintenance purpose, or during observation when meteo conditions allow to re-open.

Package Assignment:  Enclosure Subsystem.

Preconditions: 

• Enclosure sub-system is ONLINE
• Key button in Remote mode

  Interface:  IfEnclosure.GlobalStatus.LocalStatus

• Meteo conditions are OK (Wind, Humidity, Temp. Dew point etc...)
• AC is switched Off

  Interface:  IfAirConditioning.Status

Basic Course: 

• Send command OPEN <BOTH|NORTH|SOUTH> [,<angle>] to open the enclosure shell(s) of the specified angle, defaulting to fully open, for both, front or rear shell.
  Exception Course: Command failed
• ATCS sends the command to the Enclosure sub-system

  Interface:   IfEnclosure.Control.Open,  IfEnclosure.Control.OpenFront,  IfEnclosure.Control.OpenRear

  Exception Course: Command failed
  Postcondition: Enclosure shell(s) open of the given angle

  Interface:   IfEnclosure.Control.OpenStatus,  IfEnclosure.Control.OpenFrontStatus,  IfEnclosure.Control.OpenRearStatus

• ATCS returns OK reply

Exception Course: Command failed

• ATCS returns ERROR reply
  Postcondition: Enclosure is not or partially open

Postconditions: 

• The enclosure shell(s) is(are) open of the given angle

  Interface:   IfEnclosure.Control.OpenStatus,  IfEnclosure.Control.OpenFrontStatus,  IfEnclosure.Control.OpenRearStatus

• The seals are deflated

  Interface:   IfEnclosure.Seals.SealsDeflatedStatus

Issues to be Determined or Resolved:  Check with AMOS ICD for the status of the enclosure (detailed Dome/Seals).
Check range of shell opening angle [0 is Closed; 90 is Open]

Notes: There is one single command to open/close the enclosure; the AMOS PLC takes care of inflating/deflating the seals as part of the command. It is AMOS responsibility to ensure the enclosure gets closed when required.

Last modified: Wed Oct 30 17:06:22 UTC 2002