ABL w/ the Rumba Board

[jasay]

I'll be honest... I could do without the ABL and just have an adjustible offset when homing for Z and i would be gloriously happy... because if the glass is level then abl isnt needed and a number to adjust closeness to the bed makes life so much easier than turning a screw

I don't have ABL, but like you wish I could auto adjust the initial offset. Could you change this line in Marlin to "1"?

  #defineAUTO_BED_LEVELING_GRID_POINTS2

[TechMasterJoe]

I'll be honest... I could do without the ABL and just have an adjustible offset when homing for Z and i would be gloriously happy... because if the glass is level then abl isnt needed and a number to adjust closeness to the bed makes life so much easier than turning a screw

enable Z baby stepping in the firmware and keep software limit min travel false
then under tuning once you start a print you can shift up and down in .01mm steps it's very fine control i just do skirts like 4 times and adjust while it's printing the skirt
keep safe home Z on and keep the Z probe just keep your bed level and disable ABL or just don't call G29 and test it out

I don't have ABL, but like you wish I could auto adjust the initial offset. Could you change this line in Marlin to "1"?

  #defineAUTO_BED_LEVELING_GRID_POINTS2

no it will fail to probe and clear Z i will talk to thinkyhead about adding it

[jasay]

Interesting TechMasterJoe. Is the on the fly adjustment done on the LCD?

[SgtToe]

I have a question, I thought that ABL used the sensor to measure the height of the bed and then adjust the two z motors independently to compensate. However, I am hooking my z motors up and the "z motor cable" is missing and Colin said I can just plug one motor into the pins and the other into the screw terminals. But that means that both motors are being driven at the same time and could not be adjusted independently. What am I not understanding?

[jasay]

The two z motors move in sync. The ABL measures the bed and then moves the entire z axis up and down to compensate for where the bed is higher or lower (so the nozzle remains the same distance from the glass for the entire layer). If the motors moved independently you would be changing the angle of the nozzle relative to the bed (and therefore also it's x position) as well as the height.

[Effnrad]

This is a really old post, but do you have a version of rumba firmware with ABL available. The old link is broken.