Ksp reference Manual

See Also 
on ui_update
2.13. on ui_update
on ui_update
UI update callback, executed with every GUI change in KONTAKT
Remarks
This command is triggered with every GUI change in KONTAKT, so use it with caution.
Examples
on init
declare ui_knob $Volume (0,1000000,1)
set_knob_unit ($Volume,$KNOB_UNIT_DB)
set_knob_defval ($Volume,630859)
$Volume := _get_engine_par ($ENGINE_PAR_VOLUME,-1,-1,-1)
set_knob_label ($Volume,_get_engine_par_disp...
($ENGINE_PAR_VOLUME,-1,-1,-1))
end on
on ui_update
$Volume := _get_engine_par ($ENGINE_PAR_VOLUME,-1,-1,-1)
set_knob_label($Volume,_get_engine_par_disp...
($ENGINE_PAR_VOLUME,-1,-1,-1))
end on
on ui_control ($Volume)
_set_engine_par($ENGINE_PAR_VOLUME,$Volume,-1,-1,-1)
set_knob_label ($Volume,_get_engine_par_disp...
($ENGINE_PAR_VOLUME,-1,-1,-1))
end on
Mirroring instrument volume with a KSP control