With filament sensor detection, the printer will be able to recognize if the connection with the sensor was interrupted (e.g. broken wire or disconnected cable) and take appropriate action based on your settings.
This feature was activated with firmware version 3.9.0 and requires revision 0.4 of the IR filament sensor. The compatible version of the sensor has a red PCB and was introduced in 2019 (picture below).
Revision 0.4 of the sensor chip is the only one that is red.
In the Support -> Fil. sensor menu, information about the revision of the sensor will be displayed. Three possible states are defined:
It measures the voltage from the sensor which corresponds to a certain state:
In the Support > Voltages menu, a new value will now be displayed regardless of the version of the sensor: “IR: x.xxV”. This value represents the actual voltage measured on the pin of the filament sensor.
In the Menu > Settings > HW setup > FS action you can set the printer's response to an unexpected change in the filament sensor state:
The filament sensor detection procedure is an automatic part of the Self test or Calibration Wizard. However, if you skip the wizard there is a new submenu found in LCD menu ->Settings -> HW settings -> Fsensor Detection. Here the sensor revision recognition can be triggered manually for the MK3S printer. The MK3S with the MMU2S unit must run the Selftest.
The process is fully automatic and the printer enables the new feature for the revision 0.4 only when all of the following conditions are met: