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
Blair Thompson