Starlight Xpress SXV-AOLF - Manual (Page 13)

Handbook for the Starlight Xpress AOL unit Issue 1 21/5/2010
Various different functions can be triggered by ‘abnormal’ input pulse patterns. The most
useful of these is the ‘centre’ mode, which should be used before beginning any guiding
sequence. In this, the inputs are all taken low and then simultaneously released. The AO
unit will then rapidly cycle between its limit switches and adjust the window to be
centred in the dynamic range and normal to the incoming light. Other functions include
the transmission of commands through the AO system to the mount (for ‘bumping’ the
mount position) and various setup modes, mostly used for calibration during assembly.
Please note that mount commands in serial mode can take place while further AO
commands are being received and acted upon. This allows the AO unit to follow the
mount correction and ‘back off’ the AO error without trailing the image. This is not
available in parallel mode at the present time, but may be added later. Be careful not to
send multiple commands without allowing time for the previous one to complete.
The command list for parallel mode
Please note that negative logic is used for all commands – an ‘active’ input is pulled
down to the ground (0v) rail. The directions of movement are based on an inverted image
and with the AO unit arranged with its North-South axis at 90 degrees to the Declination
axis.
Guiding functions
East North South West Function
0 0 0 0 Find Centre /
Switch from
serial to parallel
mode
1 1 1 0 AO West
1 1 0 1 AO South
1 0 1 1 AO North
0 1 1 1 AO East
0 0 0 1 Mount West
0 0 1 0 Mount South
0 1 0 0 Mount North
1 0 0 0 Mount East
0 0 1 1 Force low
motor speed
1 1 0 0 Enter set up
mode
Set up mode functions