Topics created by carlacda

@droftarts said in G29 S0 if G29 S1 not loaded:

Object Model

Hi Ian,
many thanks for your idea. It did work perfectly.
Here below my implementation in start.g

if {move.compensation.type}=="none" echo {"Bed probing started"} G29 S0 ; Probe the bed, save height map to "heightmap.csv" and enable mesh bed compensation echo {"Bed probing complete"} else echo {"Bed compensation already loaded. Bed probing skipped."}

David

@o_lampe said in 24V PS_ON BOARD FOR GENERIC POWER SUPPLY:

@carlacda
The Darlington Transistor would produce ~20W of heat when switched on! How do you want to cool it down?
Don't you think, the PS_ON circuit of the Duet can switch a BC337 without the 74HC driver?

IMHO, the basic idea to have a 5V brick fed from Mains voltage is intriguing, but the Darlington transistor is a bad idea. Why not use a MOSFet instead?

I agree. In our automatic test equipment for Duet 2 we use a P-channel mosfet to switch 12V and 28V supplies to the Duet under test. Also we slowed down the turn-on time a little using a R-C network on the gate, in order to limit the surge current when the mosfet turns on (at the expense of temporarily increased power dissipation).

When we used the same equipment to test Duet 3, the 28V mosfet failed after a while. The Duet 3 has more capacitance on the VIN rail, so we had to switch to a mosfet with a higher peak current capacity.