Hi,

Im printing with relatively big nozzles at the moment (1mm with 20-30mms) including the cooling Im running into thermal runaway really quickly, so to get the maximum out of my printer it would be great to show the duty cycle on the display.

Pronterface shows the duty cycle when printing tethered so the info is there, is there any way to program marlin to show that variable on the display?

Cheers

By duty cycle I presume you mean percentage complete?

not easily

The computer has access to the entire file, so it can load it, find out how long it is, show you the progress

The controller doesn't know the file length, it has only seen what has been sent to the printer.
Even loading from sd, it just load the file line by line, no way to find out how long it is... (that I know of, might have changes since last I looked)

easiest way would be to add a gcode expect n-many lines, then it could give a percentage done.

If you meaning time to competing estimate that’s even harder, need to actually do analysis of the file, feed rates per move, number of lines.. even that is only a guess as it doesn’t know max feedrates or acceleration settings from printer

By duty cycle I mean how much power is going to the hotend. If it heats 100% and cant keep the temp either because the thermistor has an error or the material is taking too much heat out we get thermal runaway.