Use Case:  Set M2 Tilt Angles

Description:  Set M2 tilt position. This case is used during telescope alignment procedure at begining of the night and/or whenever required by VLTICS-ISS/INS.

Role(s)/Actor(s): 
Primary: Operator, Maintenance
Secondary: M2

Priority: Critical

Performance: 1 second

Frequency:  Asynchronous, typically while alignement procedure, up to a couple of times per minute.

Package Assignment:  M2 Subsystem.

Preconditions: 

• M2 is ONLINE

Basic Course: 

• Send command SETTILT <alpha,beta> to tilt M2 with given tilt angles (alpha,beta)
  Exception Course: Illegal tilt angles
  Exception Course: Command failed
• ATCS sends the command to M2 sub-system

  Interface:  IfM2.Tilting.SetAbs,  IfM2.Tilting.SetRel

  Exception Course: Command failed
• ATCS returns OK reply

Exception Course: Illegal tilt angles

• Tilt angle out of range (|tilt| < 30 arcsec)
  ATCS returns ERROR reply

Exception Course: Command failed

• ATCS returns ERROR reply

Postconditions: 

• M2 at given tilt angles

Issues to be Determined or Resolved: 

Notes: At INIT time, the mirror is moved at the configured tilt angles, configurable in the OLDB (in mm)

Last modified: Mon Nov 19 14:29:43 UTC 2001