Instead of adding a momentary switch to fake the insertion of the card I have modified the ultralcd menu item:
Card Menu -> Refresh
to reinitialise the card providing that the SDCARDDETECT pin has been set to -1 in the pins.h file. This requires one less switch on the front panel and the refresh menu item is in the most relevent place for a user who wishes to inert a card and then print from it.
It also means that the "Card inserted" messages do not bother the users of these card readers (they dont make sense for users without SCCARDDETECT)
I find that the PID routine works better when the cooling fan is switched on
at the beginning of a warm up routine. Otherwise when you enable the fan
just before a print, you have a delay as the PIDre-adjusts.
This should also be safer as most cooling fans are directed at the hot -ends
thermal barrier!
Instead of a single pre-heat, now there is pre-heat ABS and PLA options
Added defines to the configuration file to adjust preheat temperatures for both