Possible G28 interpretation problem?  

Re: Possible G28 interpretation problem?

Please download latest drivers 1.7.1. - this includes updated models where G28 at the end is replaced with "G1 X10 ; home X axis" to home just the X axis, without invoking auto calibration routine.

Re: Possible G28 interpretation problem?

Hi there,

I will do as you suggest. Will that also change the normal G28 which does the z calibration twice?

[update]
I downloaded the update, but notice that the Prusa3D\Slic3r settings MK2\simple.ini file contains the line:
end_gcode = M104 S0 ; turn off temperature\nM140 S0 ; turn off heatbed\nG28 X0 ; home X axis\nM84 ; disable motors

It's up to date on the "Original Prusa i3 MK2.ini" file however.

Re: Possible G28 interpretation problem?

That is correct - for simple mode this needs to be updated. Somehow I expected that we are talking about default Original Prusa i3 MK2.ini which is preferred.

Re: Possible G28 interpretation problem?

G28 behaviour have been fixed in 3.0.3.

Re: Possible G28 interpretation problem?

David

No it has only been amended and not fixed. A G28 Z0 also homes the X and Y axis, which is still incorrect...

Peter

Re: Possible G28 interpretation problem?

Peter,

I'm pretty sure with auto bed leveling you cannot run a G28 Z0 without first homing the X and Y axis.

Re: Possible G28 interpretation problem?

Richard

GCode commands should do exactly what they have been designed to do. It is not for Prusa Research to customise GCodes for their product; they should make their product match the existing GCode system which is already more than adequate, rather than going down a proprietary route.

There is already a GCode command (G29) for carrying out the Z calibration; ideally that should have been used, but instead, a decision was taken to mess about with and add extensions to G28.

Initially, G28 was amended such that any G28 command homed X, Y and Z and ran the calibration. Unfortunately, my version of Cura ran G28 X0 Y0 at the end of a print. That was quite a disaster.

Now G28 Z0 also homes X and Y; that is not in accordance with standard GCodes and is wrong.

G28 should not run the Z calibration, but for this printer, I agree that to avoid problems, it should only run the calibration when issued without any parameter and then only when the extruder is above minimum print temperature.

Running the Z calibration when the printer is cold and with blobs of plastic stuck to the nozzle can prevent the probe from triggering and potentially cause damage to the printer.

Peter

P.S. Apologies for the rant...

P.P.S Yes you can move the extruder to Z = 0.2 without homing X and Y, based on positional data stored in firmware.

Re: Possible G28 interpretation problem?

Peter,

Don't worry about the rant. 😀

I don't think that Prusa Research had much say in the matter. I believe this came down the Marlin development pipe. I'm pretty sure that the other machines I have with ABL work the same. I could be wrong because I haven't used them since the MK2 but I'll try to fire one up tonight to confirm.

Re: Possible G28 interpretation problem?

Richard

Not according to this: http://reprap.org/wiki/G-code#G28:_Move_to_Origin_.28Home.29

Delta printers home all on any G28, but this ain't a delta...

Peter