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Add "Thermal Runaway Protection" feature

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This is a feature to protect your printer from burn up in flames if it
has a thermistor coming off place (this happened to a friend of mine
recently and motivated me writing this feature).

The issue: If a thermistor come off, it will read a lower temperature
than actual. The system will turn the heater on forever, burning up the
filament and anything
else around.

After the temperature reaches the target for the first time, this
feature will start measuring for how long the current temperature stays
below the target minus _HYSTERESIS (set_temperature -
THERMAL_RUNAWAY_PROTECTION_HYSTERESIS).

If it stays longer than _PERIOD, it means the thermistor temperature
cannot catch up with the target, so something *may be* wrong. Then, to
be on the safe side, the system will he halt.

Bear in mind the count down will just start AFTER the first time the
thermistor temperature is over the target, so you will have no problem
if your extruder heater takes 2 minutes to hit the target on heating.
This commit is contained in:
alexborro
2014-06-30 15:22:37 -03:00
committed by cocktailyogi
parent 2096188ac3
commit 50b4e86f75
3 changed files with 117 additions and 0 deletions
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38
Marlin/Configuration.h
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@ -251,6 +251,44 @@
#define EXTRUDE_MINTEMP 170
#define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.
/*================== Thermal Runaway Protection ==============================
This is a feature to protect your printer from burn up in flames if it has
a thermistor coming off place (this happened to a friend of mine recently and
motivated me writing this feature).
The issue: If a thermistor come off, it will read a lower temperature than actual.
The system will turn the heater on forever, burning up the filament and anything
else around.
After the temperature reaches the target for the first time, this feature will
start measuring for how long the current temperature stays below the target
minus _HYSTERESIS (set_temperature - THERMAL_RUNAWAY_PROTECTION_HYSTERESIS).
If it stays longer than _PERIOD, it means the thermistor temperature
cannot catch up with the target, so something *may be* wrong. Then, to be on the
safe side, the system will he halt.
Bear in mind the count down will just start AFTER the first time the
thermistor temperature is over the target, so you will have no problem if
your extruder heater takes 2 minutes to hit the target on heating.
*/
// If you want to enable this feature for all your extruder heaters,
// uncomment the 2 defines below:
// Parameters for all extruder heaters
//#define THERMAL_RUNAWAY_PROTECTION_PERIOD 40 //in seconds
//#define THERMAL_RUNAWAY_PROTECTION_HYSTERESIS 4 // in degree Celsius
// If you want to enable this feature for your bed heater,
// uncomment the 2 defines below:
// Parameters for the bed heater
//#define THERMAL_RUNAWAY_PROTECTION_BED_PERIOD 20 //in seconds
//#define THERMAL_RUNAWAY_PROTECTION_BED_HYSTERESIS 2 // in degree Celsius
//===========================================================================
//===========================================================================
//=============================Mechanical Settings===========================
//===========================================================================