Package: Nasmyth Focus Device

Description:  Control of the Nasmyth Focus related devices, like Nasmyth Wheel and the Nasmyth Beacon.

Package name: nfd

Inheritance:  LCU Server Framework <<SubSystem>>lsfSERVER

Controlled HW Devices: 

• <<Motor Device>>wheel:lsfMOTOR

Controlled SW Devices: 

• <<Software Device>>aubcn:lsfSOFTDEV
  • Database: atnfdDB_BEACON:lsfDB_SOFTDEV

  Deployment:  Altitude LCU: atnfdServer

  Use Case diagram: 

  
  

  Class diagram: 

  
  

  Architecture: 

  This Software Device is instantiated from the LCU Server Framework lsf.
  The sub-class <<SW Device>>atnfdServer:lsfSERVER is composed of an instance of the motor class <<Motor Device>>wheel:lsfMOTOR and of one instance of the software device class <<Software Device>>aubcn:lsfSOFTDEV.

  

  The Software Device atnfdServer provides the following Specific Commands for the control of the Nasmyth wheel:

  • SETPATH and GETPATH: to set and get the wheel position.
  and 3 Specific Commands for the control of the 2 beacons:
  • SETNBCN: to switch On and Off the beacon.
  • GETNBCN: to get the beacon status.
  • SETNBLV: to set the light level of the beacon.

   

  Command SETPATH / GETPATH

  These commands are transient instances resp. of the classes:
  <<Control>>nfdSETPATH:lsfCOMMAND_HANDLER and
  <<Control>>nfdGETPATH:lsfCOMMAND_HANDLER.

  They invoke the inherited method lsfMOTOR::lsfMotorMoveAbs(char *name[], vltDOUBLE offset[]) and lsfMOTOR::getPosition():

   

  Sequence diagram:

  

  Activity diagram:

  

  The Nasmyth wheel is intended to be used mainly for optical alignments, thus only the position mode is relevant here. The positions are accessible via their names (see MCM Named Positions) to which an offset may be added as required (only for both alignment tools):

  • FREE: Free hole.
  • RETRO: Flat retro-reflecting mirror.
  • TOOL1: Alignment tool #1.
  • TOOL2: Alignment tool #2.
  The default (observation) position is FREE.

   

  Commands SETNBCN, GETNBCN, SETNBLV

  These 3 commands are transient instances resp. of the classes:
  <<Control>>nfdGETNBCN:lsfCOMMAND_HANDLER,
  <<Control>>nfdSETNBCN:lsfCOMMAND_HANDLER,
  <<Control>>nfdSETNBLV:lsfCOMMAND_HANDLER.

  They invoke the inherited methods lsfSOFTDEV::lsfForwardCommand(). The commands are routed to the module aubcn, that is the generic VLTI beacon controller:

   

  Sequence diagram:

  

  Activity diagram:

  

  There are 2 Nasmyth beacons associated resp. to the 2 alignment tools of the Nasmyth wheel. The beacon may be switched on only when the wheel is in one of the tool positions(TOOL1 or TOOL2); when moving the wheel out of these positions (e.g. to FREE or RETRO) the associated beacon is automatically switched off. The selection of the wavelength associated to each beacon is a manual operation where the optical fibers are plugged in two of the 3 laser beacons available on the board. The Nasmyth beacon may not be switched on together with the pupil beacon.

  Command Definition Table: atnfdServer.cdt

  Command Interpreter Table: atnfdServer.cit

  Reuse from VLT TCS:  New package

  Issues to be Determined or Resolved: None

  
  

  Last modified: Wed Jun 27 08:10:22 UTC 2001