Hi all,
Support for a new option to replace PID heating for the hotend has just been merged. This seems to have a lot better control over the hotend heater, and at least in my testing, seems to have a better profile for heating.
You can find the new setting in the Firmware Builder as per the below screenshot.
The documentation is still being processed - but in simple terms, the new command M306
is now added.
The basic options are:
A<watts/kelvin> Ambient heat transfer coefficient (no fan).
C<joules/kelvin> Block heat capacity.
E<extruder> Extruder number to set. (Default: E0)
F<watts/kelvin> Ambient heat transfer coefficient (fan on full).
P<watts> Heater power.
R<kelvin/second/kelvin> Sensor responsiveness (= transfer coefficient / heat capcity).
T Autotune the active extruder.
Once you flash your printer with a MPC enabled firmware, set your heater power as per the rating - most printers have either 30W or 40W heaters (mine is 70W), so you’d run:
M306 P30 ; 30W heater
M306 P40 ; 40W heater
M306 P70 ; 70W heater
Once that’s done, run the autotune:
M306 T
At this point, the rest of the setup is automatic.
When it finishes, save your settings via M500
.
On my personal printer, the heatup profile when from this with an overshoot of 10-15c when using PID:
To this when autotuned using MPC:
I look forward to seeing peoples feedback on this brand new feature.