<p>Normally you wouldn't use the <code>MANUAL_xyz_HOME_POS</code> at all.</p>
<p>Home your machine.
Use a caliper or ruler to measure the distance between the nozzle and the edges of the print bed in both the X and Y direction.
If the nozzle was <em>off</em> the bed in both directions, input these measurements as <em>negative</em> <code>X_MIN_POS</code> and <code>Y_MIN_POS</code> values.
If it was <em>over</em> the bed in either of those directions, you'll need to input them as <em>positive</em> positions.</p>
<p>That should result in your nozzle to be exactly on the edge of the bed after a</p>
<pre><code>G28 X Y
G1 X0 Y0
</code></pre>
<p>movement.</p>

CC BY-SA 4.0
2020-10-22T18:10:49.310Z
Oh my god, that is what I did and it didnt work, so then I wondered what I did wrong and came here to ask. But it did work! I just didn't flash the firmware, I must have forgotte nto turn the printer off and on again!
JustAGuy
CC BY-SA 4.0
2020-10-22T18:11:47.587Z
Still, how do I set the probe offsets or whatever correctly to not hit the clips? And is 5mm less of build volume normal?
JustAGuy
CC BY-SA 4.0
2020-10-23T05:40:28.607Z
You'll first want to set the probe offsets via `NOZZLE_TO_PROBE_OFFSET` relative to the nozzle.
The offsets for the actual probing would be set with `PROBING_MARGIN`, which defaults to 10 mm.
towe
CC BY-SA 4.0
2020-10-22T09:59:39.203Z
2020-10-22T09:59:39.203Z
towe
<p>I am using an Ender 3 and I have just upgraded to the Hero Me Gen 5 fan duct adapter. This has shifted the nozzle position. I also flashed some new Marlin 2 firmware and in the Hero Me manual it says to uncomment and change <code>#define MANUAL_Y_HOME_POS -9</code> to suit this change in nozzle position.</p>
<p>This has, however, not given me the right results. It did not center my prints but actually let the Y-axis grind upon going to <code>Y235</code>. Additionally, I noticed, that my printer must have been off-center from the beginning, because the X position of the nozzle has not changed due to the installation, but the printer homes to a point 5 mm inside the bed perimeters.</p>
<p><strong>So, if my printers endstops dictate an original home position of 3 mm <em>inside</em> the bed area for X and 15 mm outside the bed area for Y, how do I set this up correctly in Marlin 2?</strong></p>
<p>I think the relevant parts are</p>
<pre><code>// The size of the print bed
#define X_BED_SIZE 235
#define Y_BED_SIZE 235

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS 5
#define Y_MIN_POS -15
#define Z_MIN_POS 0
#define X_MAX_POS 250
#define Y_MAX_POS 240
#define Z_MAX_POS 230
...
// Manually set the home position. Leave these undefined for automatic settings.
// For DELTA this is the top-center of the Cartesian print volume.
//#define MANUAL_X_HOME_POS 0
//#define MANUAL_Y_HOME_POS -9
//#define MANUAL_Z_HOME_POS 0
</code></pre>
<p>This is my idea, I would let the manual home pos be commented out as I do not know what it does. However, I also want the software endstops to correcly work as to not let the printer destroy it <em>aaaaand</em> my BLTouch to probe the bed and not the air or my bed clips using UBL when doing 3-point probing. Would this be correct? Where do I have to look to let the printer consider my bed clips(only 10 mm on both ends of the y-axis side of the bed)?</p>

CC BY-SA 4.0
2020-10-22T13:53:07.153Z
This question is very similar, and therefore a duplicate to [Recalibrating Home-position](https://3dprinting.stackexchange.com/questions/6399/recalibrating-home-position) and [How to center my prints on the build platform? (Re-calibrate homing offset)](https://3dprinting.stackexchange.com/questions/6375/how-to-center-my-prints-on-the-build-platform-re-calibrate-homing-offset). The answer to those questions describe in detail what you need to do. First question is specific for the Ender 3.
0scar
<marlin><firmware><homing><endstop>
How to set Home Offsets and Manual Home definitions in Marlin correctly?
JustAGuy
# How to set Home Offsets and Manual Home definitions in Marlin correctly?

(Asked by: username_0 on 2020-10-21)

I am using an Ender 3 and I have just upgraded to the Hero Me Gen 5 fan duct adapter. This has shifted the nozzle position. I also flashed some new Marlin 2 firmware and in the Hero Me manual it says to uncomment and change `#define MANUAL_Y_HOME_POS -9` to suit this change in nozzle position.

This has, however, not given me the right results. It did not center my prints but actually let the Y-axis grind upon going to `Y235`. Additionally, I noticed, that my printer must have been off-center from the beginning, because the X position of the nozzle has not changed due to the installation, but the printer homes to a point 5 mm inside the bed perimeters.

**So, if my printers endstops dictate an original home position of 3 mm *inside* the bed area for X and 15 mm outside the bed area for Y, how do I set this up correctly in Marlin 2?**

I think the relevant parts are

```
// The size of the print bed
#define X_BED_SIZE 235
#define Y_BED_SIZE 235

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS 5
#define Y_MIN_POS -15
#define Z_MIN_POS 0
#define X_MAX_POS 250
#define Y_MAX_POS 240
#define Z_MAX_POS 230
...
// Manually set the home position. Leave these undefined for automatic settings.
// For DELTA this is the top-center of the Cartesian print volume.
//#define MANUAL_X_HOME_POS 0
//#define MANUAL_Y_HOME_POS -9
//#define MANUAL_Z_HOME_POS 0

```

This is my idea, I would let the manual home pos be commented out as I do not know what it does. However, I also want the software endstops to correcly work as to not let the printer destroy it *aaaaand* my BLTouch to probe the bed and not the air or my bed clips using UBL when doing 3-point probing. Would this be correct? Where do I have to look to let the printer consider my bed clips(only 10 mm on both ends of the y-axis side of the bed)?

**Tags:** marlin, firmware, homing, endstop

> **Comments:**
> **username_1**: This question is very similar, and therefore a duplicate to [Recalibrating Home-position](https://3dprinting.stackexchange.com/questions/6399/recalibrating-home-position) and [How to center my prints on the build platform? (Re-calibrate homing offset)](https://3dprinting.stackexchange.com/questions/6375/how-to-center-my-prints-on-the-build-platform-re-calibrate-homing-offset). The answer to those questions describe in detail what you need to do. First question is specific for the Ender 3.  

---

## 1 answers

### Answer by username_2 on 2020-10-22. Score: 3 | Accepted answer

Normally you wouldn't use the `MANUAL_xyz_HOME_POS` at all.

Home your machine.
Use a caliper or ruler to measure the distance between the nozzle and the edges of the print bed in both the X and Y direction.
If the nozzle was *off* the bed in both directions, input these measurements as *negative* `X_MIN_POS` and `Y_MIN_POS` values.
If it was *over* the bed in either of those directions, you'll need to input them as *positive* positions.

That should result in your nozzle to be exactly on the edge of the bed after a

```
G28 X Y
G1 X0 Y0

```

movement.

> **Comments:**
> **username_0**: Oh my god, that is what I did and it didnt work, so then I wondered what I did wrong and came here to ask. But it did work! I just didn't flash the firmware, I must have forgotte nto turn the printer off and on again!  
> **username_0**: Still, how do I set the probe offsets or whatever correctly to not hit the clips? And is 5mm less of build volume normal?  
> **username_2**: You'll first want to set the probe offsets via `NOZZLE_TO_PROBE_OFFSET` relative to the nozzle. The offsets for the actual probing would be set with `PROBING_MARGIN`, which defaults to 10 mm.  

---

