I really don't know what I am doing wrong. Since changing my bed level sensor from left of the extruder to back mount, it doesn't work proper anymore and I have some fundamental thing I don´t understand. My settings:



Now the first thing I don´t get is how especially LEFT_PROBE_BED_POSITION works. Cause when I set it to 11 here (I want it to measure 5 steps from the home) it measures almost in the middle not at the left edge. It seems that I need to subtract from where the printer homes (X99 Y45) which is why I choose X-89 but then it seems that the printer assumes a totally wrong size of the bed and ties to print off the bed...

Here where it measures:

16:02:44.774 : Bed x: -89.00 y: 10.00 z: 1.28
16:02:59.326 : Bed x: 90.00 y: 10.00 z: 1.23
16:03:13.466 : Bed x: 90.00 y: 145.00 z: 1.28
16:03:27.959 : Bed x: -89.00 y: 145.00 z: 1.30

Measures exactly where I want it to but the values make no sense. The first probe is actually about X10 Y10 but the display shows X-95 Y-50 while the above values are from the slicer log. That makes absolutely no sense to me!

I hope anyone can enlighten me.

  • $\begingroup$ How to set up the area for the sensor to reach, please read: "How to set Z-probe boundary limits in firmware when using automatic bed leveling?" This explains exactly what you need to do to determine the correct values. $\endgroup$
    – 0scar
    Mar 15 '20 at 18:04
  • $\begingroup$ Yes I use that of course but according to this manual my settings would be the following: #define LEFT_PROBE_BED_POSITION 16 #define RIGHT_PROBE_BED_POSITION 210 #define BACK_PROBE_BED_POSITION 210 #define FRONT_PROBE_BED_POSITION 70 If I would use these settings my extruder would keep crashing into the frame. The manual might be good to explain but for calculation it seems wrong... $\endgroup$ Mar 16 '20 at 10:45
  • $\begingroup$ Also everything what I set at FRONT_PROBE_BED_POSITION higher that 60 causes the error "The Y axis probing range is not enough to fit all the points defined in AUTO_BED_LEVELING_GRID_POINTS". $\endgroup$ Mar 16 '20 at 11:23
  • $\begingroup$ If I set FRONT_PROBE_BED_POSITION to zero my printer display shows coordinates x: 24 and y: -60 as if it assumes the sensor be in front... But isn´t that defined by the offset from extruder? Both + values which means the sensor is on the back right. $\endgroup$ Mar 16 '20 at 11:41
  • $\begingroup$ The manual works perfectly, the calculations are fine, you just need to set the correct endstop to origin offsets. To be able to help you, you need to post the following things in your question, the X and Y offset for the probe and the X and Y offset for the endstop to origin. You should also mention that you are using Marlin 1.1.9, for 2.x it works differently, but it is also described in the answer. $\endgroup$
    – 0scar
    Mar 16 '20 at 11:52