<p>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:</p>

<pre><code>#define LEFT_PROBE_BED_POSITION -89
#define RIGHT_PROBE_BED_POSITION 90
#define BACK_PROBE_BED_POSITION 145
#define FRONT_PROBE_BED_POSITION 10

#define X_PROBE_OFFSET_FROM_EXTRUDER 6
#define Y_PROBE_OFFSET_FROM_EXTRUDER 60
#define Z_PROBE_OFFSET_FROM_EXTRUDER -1.4
</code></pre>

<p>Now the first thing I don´t get is how especially <code>LEFT_PROBE_BED_POSITION</code> works. Cause when I set it to <code>11</code> 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...</p>

<p>Here where it measures:</p>

<pre><code>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
</code></pre>

<p>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!</p>

<p>I hope anyone can enlighten me.</p>

CC BY-SA 4.0
2020-03-15T18:04:32.387Z
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?](/q/8153)" This explains exactly what you need to do to determine the correct values.
0scar
CC BY-SA 4.0
2020-03-16T10:45:37.423Z
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...
magichappens
CC BY-SA 4.0
2020-03-16T11:23:50.353Z
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".
magichappens
CC BY-SA 4.0
2020-03-16T11:41:38.400Z
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.
magichappens
CC BY-SA 4.0
2020-03-16T11:52:18.050Z
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.
0scar
CC BY-SA 4.0
2020-03-16T13:07:24.570Z
My offsets are in my first post. I think I figured it out also I don´t know how... I was finally able to set FRONT_PROBE_BED_POSITION to something above 60 and that seems to work. That value always produced negative values in my y coordinates which somehow screwed up my print coordinates as well. Since the nozzle is still not at the edge while the display shows x:10 y:0 it is still weird but at least prints are in the middle of the bed again.
magichappens
<marlin><prusa-i3><bed-leveling>
Printer places prints off the bed after change in bed Z-probe area settings
magichappens
# Printer places prints off the bed after change in bed Z-probe area settings

(Asked by: username_0 on 2020-03-15)

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:

```
#define LEFT_PROBE_BED_POSITION -89
#define RIGHT_PROBE_BED_POSITION 90
#define BACK_PROBE_BED_POSITION 145
#define FRONT_PROBE_BED_POSITION 10

#define X_PROBE_OFFSET_FROM_EXTRUDER 6
#define Y_PROBE_OFFSET_FROM_EXTRUDER 60
#define Z_PROBE_OFFSET_FROM_EXTRUDER -1.4

```

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.

**Tags:** marlin, prusa-i3, bed-leveling

> **Comments:**
> **username_1**: 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?](/q/8153)" This explains exactly what you need to do to determine the correct values.  
> **username_0**: 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...  
> **username_0**: 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".  
> **username_0**: 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.  
> **username_1**: 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.  
> **username_0**: My offsets are in my first post. I think I figured it out also I don´t know how... I was finally able to set FRONT_PROBE_BED_POSITION to something above 60 and that seems to work. That value always produced negative values in my y coordinates which somehow screwed up my print coordinates as well. Since the nozzle is still not at the edge while the display shows x:10 y:0 it is still weird but at least prints are in the middle of the bed again.  

---

## 0 answers

