try to be smarter than your controller board  

try to be smarter than your controller board

bone head mistake of the day by me I was printing a petg temperature tower and to shift the temp of the hot end I was using this gCode at the level change
;BEFORE_LAYER_CHANGE

{if layer_z == 7.8}M104 S255{endif};
{if layer_z == 14.6}M104 S250{endif};
{if layer_z == 21.40}M104 S245{endif};
{if layer_z == 28.0}M104 S240{endif};
{if layer_z == 34.8}M104 S235{endif};
{if layer_z == 41.4}M104 S230{endif};
{if layer_z == 48.2}M104 S225{endif};
is what I thought I had entered but the print with a piercing alarm and Err. MAXTEMP just at point of this line
{if layer_z == 41.4}M104 S230{endif}; the first time I was not watching the print so i missed it the max temp scrambled things a bit an I had to hit The X paddle under the lcd control knob to restore normal function and try again

well this time I am watching as the gcode attempts to set the next temp of 230c... and to my shock it attempts to set 2300c... the actual hot end temp rushes up to something over 300c as I rush to get over to the printer and hit abort... I then take another look at the
;BEFORE_LAYER_CHANGE

{if layer_z == 7.8}M104 S255{endif};
{if layer_z == 14.6}M104 S250{endif};
{if layer_z == 21.40}M104 S245{endif};
{if layer_z == 28.0}M104 S240{endif};
{if layer_z == 34.8}M104 S235{endif};
{if layer_z == 41.4}M104 S2300{endif};
{if layer_z == 48.2}M104 S225{endif};

yes it was just trying to do what I told it to....
now I have been programing computers since 1967 with Fortran on punch cards on a PDP-10 main frame and I know better than to use dangerous commands that control hardware with out quintuple proof reading including reading it backwards.... but I am now in my 70s and my eyes and mind are not those of a teenaged wiz kid...
just a heads up when ever you plug hotted temperatures into your gcode