D40 Power On Options

The unit can be configured to start-up with a preset active.

Press the bulb button to open the Presets &  Sequences menu.

Select preset. You can disable the preset from this screen.

Page 87 from the manual: http://www.etcconnect.com/docs/docs_downloads/manuals/DesireSeries_User_Manual_1.6.0_revA.pdf shows the menu structure.

Marcus

If you really need to be particular about the speed and timing of this start-up fade in, you could set the fixture to automatically run a non-repeating sequence, where preset 1 is all off and preset 2 is the setting you want the fixture to remain at.  You can adjust the wait time and fade time of this whole process.  Of course, this solution will only work if there is no DMX signal going to the fixture.

As you know, the fixture takes a few seconds to boot up (there is a lot of processing power that needs to initialize).  If DMX is operational, the fixture must assume that the DMX setting it is receiving is where the fixture needs to be at the instant the system is all ready to go.  To assume otherwise would cause more problems than it would fix.  If this instant-on performance is problematic, the fixture really should be powered on long before it needs to produce light, so that the fade-in is controlled in real time by DMX, which is standard practice with any intelligent luminaire.