| UK Astronomy Technology Centre | Chris Tierney |
| Royal Observatory, Edinburgh | 31st March 2001 |
The wavefront sensor components accessed from this screen are all simple two-state devices.
Safety
All the NAOMI mechanism control screens display two buttons - a red "Emergency" button
and a green "Safe" button - in the top right corner of the screen.
Left clicking an "Emergency" button will immediately stop any motion by any part of the wavefront sensor or calibration unit. Thereafter, any demands for motion are rejected, until the user left clicks on any of the "Safe" buttons. Many mechanisms will then demand to be re-indexed before allowing the execution of any other motions.
Note: This safety feature has no effect on the motion of the Durham deformable mirror (DM) or fast beam-steering mirror (FSM), nor any component of the electronics associated with NAOMI.
For more information, see the NAOMI mechanism software
safety page.
CCD Camera shutter
The CCD camera shutter is either open or closed. The software causes transitions between these two states
by altering, in sequence, the levels of two TTL voltages that originate in the NAOMI XYCOM-240 card.
The user is required only to select the desired shutter state using the "Demand State" button selector, and click the "Go" Directive button. The display will then indicate that the system becomes "busy", followed shortly by "idle", at which point the transition is complete and the "Current state" indicator is updated. If the system transitions to the state "error", a message on the display will indicate the nature of the fault.
Note: A switch is installed on the shutter mechanism, which should be active when the shutter is closed and inactive
when the shutter is open. A selector button has been added to the screen, at which the user can instruct
the software _not_ to check this switch. This feature was added because, at the time of this writing, the shutter
switch is faulty.
WFS calibration source
The WFS calibration source is a lamp mounted close to the wavefront sensor pickoff. It has two states, on and off,
and is controlled using a TTL voltage from the XYCOM-240 card.
The user is required to select the desired lamp state using the "Demand State" button selector, and click the "Go" Directive button. The display will then indicate that the system becomes "busy", followed shortly by "idle", at which point the transition is complete and the "Current state" indicator is updated. If the system transitions to the state "error", a message on the display will indicate the nature of the fault.
WFS secondary camera
Note that the WFS camera is not the CCD camera that is mounted on the wavefront sensor CCD carriage
and is used to record the lenslet images.
The WFS (secondary) camera, a COHU remote-head CCD camera, is to be mounted on the NAOMI calibration unit and is designed to image the full field of view of the wavefront sensor pickoff. The camera, as far as this software is concerned, has two states: on and off, controlled using a TTL voltage from the XYCOM-240 card.
The user is required to select the desired camera state using the "Demand State" button selector, and click the "Go" Directive button. The display will then indicate that the system becomes "busy", followed shortly by "idle", at which point the transition is complete and the "Current state" indicator is updated. If the system transitions to the state "error", a message on the display will indicate the nature of the fault.
Note further that, at the time of this writing, this camera is not currently installed on the
NAOMI instrument.
Menu items
There are two items int he "Higher Displays" menu: