TemperatureSwitch is an optional module that automatically controls an output (typically to control one of the small MOSFETs) through a Switch module, based on a configurable threshold temperature.
It is commonly used to turn on/off a cooling fan or water pump to cool a 3D printer extruder hot end’s cold zone.
Simply, TemperatureSwitch turns on/off the switch.xxx where xxx is the user-defined switch.xxx = fan or misc in the default configuration files.
If the printer has multiple hot ends, TemperatureSwitch will monitor all of them and if any one goes over the threshold, will turn on the switch. It will only turn the switch off if all of them are below the threshold temperature.
Since hot ends heat up relatively quickly and cool off slowly, the polling interval for heatup and cooldown are independently configurable in the configuration file. This is done to minimize processor load during printing.
Here’s a description of the configurable parameters:
# automatically toggle a switch at a specified temperature
# useful to turn on a fan or water pump to cool the hotend
temperatureswitch.hotend.enable true # enable this module
temperatureswitch.hotend.switch fan2 # select which MOSFET to use, must match a switch configuration (fan2 below)
temperatureswitch.hotend.designator T # first character of the temperature control designator to use as the temperature sensor to monitor
temperatureswitch.hotend.threshold_temp 60.0 # temperature to turn on (if rising) or off the switch
temperatureswitch.hotend.heatup_poll 15 # poll heatup at 15 sec intervals
temperatureswitch.hotend.cooldown_poll 60 # poll cooldown at 60 sec intervals
switch.fan2.enable true # enable
switch.fan2.input_on_command M42 # gcode to turn on
switch.fan2.input_off_command M43 # gcode to turn off
switch.fan2.output_pin 2.4 # pin that controls the fan
Many temperatureswitch instances can be defined that monitor different temperatures and trigger different switches for instance one to turn a motor fan on and off also note that a readonly temperature control can be defined…
temperatureswitch.motor.enable true #
temperatureswitch.motor.switch motorfan #
temperatureswitch.motor.designator M #
switch.motorfan.enable true # enable
switch.motorfan.input_on_command M42 # gcode to turn on
switch.motorfan.input_off_command M43 # gcode to turn off
switch.motorfan.output_pin 2.4 # pin that controls the fan
# define a readonly temperaturecontrol for a motor
temperature_control.motor.enable true # Whether to activate this ( "hotend" ) module at all. All configuration is ignored if false.
temperature_control.motor.thermistor_pin 0.24 # Pin for the thermistor to read
temperature_control.motor.heater_pin nc # set to nc to make it a readonly temperature control
temperature_control.motor.thermistor EPCOS100K # thermistor name
temperature_control.motor.designator M # designator
# turn the PSU off when the hotend temp cools below 50, only do this once M1100 S1 has been executed to arm it
temperatureswitch.psu_off.enable true #
temperatureswitch.psu_off.designator T # first character of the temperature control designator to use as the temperature sensor to monitor
temperatureswitch.psu_off.switch psu # select which switch to use, matches the name of the defined switch
temperatureswitch.psu_off.threshold_temp 50.0 # temperature to trigger at when falling
temperatureswitch.psu_off.heatup_poll 30 # poll heatup every 30 seconds
temperatureswitch.psu_off.cooldown_poll 30 # poll cooldown every 30 seconds
temperatureswitch.psu_off.arm_mcode 1100 # M1100 S1 will arm it
temperatureswitch.psu_off.trigger falling # only trigger when the temp falls below after being above
temperatureswitch.psu_off.inverted false # turn the switch off when we trigger (by default switches on when rising and off when falling)
| Option | Example value | Explanation | | —— | ————- | ———– |
The TemperatureSwitch module automatically toggles a Switch module at a specified temperature (read from a TemperatureControl module).
| Option | Default Value | Description |
|---|---|---|
temperatureswitch.module_name.enable |
true |
Create and enable a new TemperatureSwitch module if set to true. |
temperatureswitch.module_name.designator |
T |
Specify which TemperatureControl module to read temperature from, must match the designator for that module. |
temperatureswitch.module_name.switch |
misc |
Specify the name of the Switch module to be toggled. |
temperatureswitch.module_name.threshold_temp |
60 |
Turn the switch ON above this temperature (in °C), and OFF below this temperature. |
temperatureswitch.module_name.heatup_poll |
15 |
Poll temperature at this frequency (in seconds) when heating up. |
temperatureswitch.module_name.cooldown_poll |
60 |
Poll temperature at this frequency (in seconds) when cooling down. |
temperatureswitch.module_name.trigger |
level |
Can be level, rising, falling - level is the default. |
temperatureswitch.module_name.inverted |
false |
Will turn the switch off when the temp > target and vice versa when set to true. |
temperatureswitch.module_name.arm_mcode |
1100 |
M code used to arm the edge triggered switch, e.g., M1100 S1 arms it. |
[!NOTE] If you want to learn more about this module, or are curious how it works, Smoothie is Open-Source and you can simply go look at the code, here.