Use Case:  Get M2 Center Position

Description:  Get M2 center 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 GETCPOS to get M2 center position (X,Y)
  Exception Course: Command failed
• ATCS sends the command to M2 sub-system

  Interface:  IfM2.Centering.GetAbs

  Exception Course: Command failed
• ATCS returns current M2 center position

Exception Course: Command failed

• ATCS returns ERROR reply

Postconditions: 

• M2 center position are returned

Issues to be Determined or Resolved: 

Notes:

Last modified: Thu Jun 28 13:28:37 UTC 2001