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reprap:anet:a8:improvement:autobedleveling [2019/04/30 09:44]
0scar [Is your Z-offset correct?]
reprap:anet:a8:improvement:autobedleveling [2021/05/09 06:32] (current)
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 ^ Sensor name  ^ Type    ^glass bed^Distance^comment^cost^link^voltage^oc^sig*^ ^ Sensor name  ^ Type    ^glass bed^Distance^comment^cost^link^voltage^oc^sig*^
-|ROKO SN04-N|NPN|no|<​3mm|the "​official"​ Anet sensor|4-15USD||10-30V(5V)|no| +|ROKO SN04-N|NPN|no|<​3 mm|the "​official"​ Anet sensor|4-15 USD||10-30 V(5 V)|no| 
-|TRONYX XY-08N|NPN|no|8mm|With Support|[[https://​www.aliexpress.com/​item/​TRONXY-3D-Printer-Auto-Leveling-Sensor-with-Auto-Feature-3D-Touch-Free-shipping/​32841886247.html?​spm=2114.search0104.3.9.291a3140JZABX2&​ws_ab_test=searchweb0_0,​searchweb201602_3_10152_10065_10151_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_10545_10696_10084_10083_10618_10307_5711215_10313_10059_10534_100031_10103_10624_10623_443_10622_5711315_10621_10620_10810_10811_5722415,​searchweb201603_2,​ppcSwitch_5&​algo_expid=4192894e-00f9-4347-9929-ef14e0fdf7c4-1&​algo_pvid=4192894e-00f9-4347-9929-ef14e0fdf7c4&​transAbTest=ae803_4&​priceBeautifyAB=0|12USD]]||6-38V(5V)|no| +|TRONYX XY-08N|NPN|no|8 mm|With Support|[[https://​www.aliexpress.com/​item/​TRONXY-3D-Printer-Auto-Leveling-Sensor-with-Auto-Feature-3D-Touch-Free-shipping/​32841886247.html?​spm=2114.search0104.3.9.291a3140JZABX2&​ws_ab_test=searchweb0_0,​searchweb201602_3_10152_10065_10151_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_10545_10696_10084_10083_10618_10307_5711215_10313_10059_10534_100031_10103_10624_10623_443_10622_5711315_10621_10620_10810_10811_5722415,​searchweb201603_2,​ppcSwitch_5&​algo_expid=4192894e-00f9-4347-9929-ef14e0fdf7c4-1&​algo_pvid=4192894e-00f9-4347-9929-ef14e0fdf7c4&​transAbTest=ae803_4&​priceBeautifyAB=0|12 USD]]||6-38 V(5 V)|no| 
-|**HallON**|Hall effect|yes|On any surface|With Connector for Anet|[[http://​hallon.garage-makezone.eu/​|10-16Euro]]|[[https://​www.thingiverse.com/​thing:​2838259|PnP and DIY kits]]|5V|no|no +|**HallON**|Hall effect|yes|On any surface|With Connector for Anet|[[http://​hallon.garage-makezone.eu/​|10-16 Euro]]|[[https://​www.thingiverse.com/​thing:​2838259|PnP and DIY kits]]|5 V|no|no 
-|LJ18A3-8-Z/​BX | NPN inductive ​   |no|8mm |[[http://​www.ebay.co.uk/​itm/​192036463186|with connector]]|[[https://​www.aliexpress.com/​item/​Promotion-LJ18A3-8-Z-BX-8mm-Approach-Sensor-NPN-NO-Switch-DC-6-36V/​32623086326.html|3USD]]| |6-36V(5V)|no|3.2µm|    +|LJ18A3-8-Z/​BX | NPN inductive ​   |no|8 mm |[[http://​www.ebay.co.uk/​itm/​192036463186|with connector]]|[[https://​www.aliexpress.com/​item/​Promotion-LJ18A3-8-Z-BX-8mm-Approach-Sensor-NPN-NO-Switch-DC-6-36V/​32623086326.html|3 USD]]| |6-36 V(5 V)|no|3.2 µm|    
-|**LJ18A3-8-Z/​BX-5V** | NPN inductive ​   |no|8mm ||[[https://​aliexpress.com/​item/​M18-8mm-sensing-DC-5V-NPN-NO-LJ18A3-8-Z-BX-5V-cylinder-inductive-proximity-sensor/​32719316657.html|6USD]]| |5V|no|3.0µm|    +|**LJ18A3-8-Z/​BX-5V** | NPN inductive ​   |no|8 mm ||[[https://​aliexpress.com/​item/​M18-8mm-sensing-DC-5V-NPN-NO-LJ18A3-8-Z-BX-5V-cylinder-inductive-proximity-sensor/​32719316657.html|6 USD]]| |5 V|no|3.0 µm|    
-|LJC18A3-H-Z/​BX |NPN capacitive|yes|1-10mm||5USD||6-36V||0.6µm@25°C [email protected]60°C+|LJC18A3-H-Z/​BX |NPN capacitive|yes|1-10 mm||5 USD||6-36 V||0.6 µm 25 °C, µm 60 °C
-|LJ12A3-4-Z/​BX|NPN Inductive|no|4mm| |2USD||6-36V+|LJ12A3-4-Z/​BX|NPN Inductive|no|4 mm| |2 USD||6-36 V
-|LJ12A3-4-Z/​BX-5V|NPN Inductive|no|4mm| |3USD| |5V|   +|LJ12A3-4-Z/​BX-5V|NPN Inductive|no|4 mm| |3 USD| |5 V|   
  
     ​     ​
  
-If (5V) is mentioned on the sensor, it has been tested that it works on the 5V provided by the Z-switch connector, but officially it need a higher voltage therefore it might not work reliably. See "​wiring chapter"​ to connect it to the 12V power supply.+If (5 V) is mentioned on the sensor, it has been tested that it works on the 5 V provided by the Z-switch connector, but officially it need a higher voltage therefore it might not work reliably. See "​wiring chapter"​ to connect it to the 12 V power supply.
  
 *)The standard deviation obtained according to the [[autobedleveling#​testing_repeatability_of_the_probe]] chapter *)The standard deviation obtained according to the [[autobedleveling#​testing_repeatability_of_the_probe]] chapter
 ==== capacitive sensors vs inductive ==== ==== capacitive sensors vs inductive ====
-  * inductive sensors are using magnetic fields for the detection. They can only detect metal. It can detect the metal under the glass, if the range of the sensor is high enough. But if the metal is deformed beneath the glass the printer will try to compensate a non-existing deformation. Also while using Inductive sensors, the detection range needs to be adjusted according to the metal which the sensor senses. They are designed for sensing Iron based metals. So for other metals, the sensing distance needs to be derated. A rough multiplier for sensing distances for various metals are given in brackets -  Steel (1.0), Stainless Steel (0.6 - 1.0), Aluminum (0.30 - 0.45), Brass (0.35 - 0.50), Copper (0.25 - 0.45). For eg: if an 8mm Inductive sensor is used to sense Aluminum, the sensing distance is actually between 2.4mm and 3.6mm. So it would be best to test the sensing distance with the sensor you purchased before installation,​ especially while using 4mm sensors along with a glass build plate.+  * inductive sensors are using magnetic fields for the detection. They can only detect metal. It can detect the metal under the glass, if the range of the sensor is high enough. But if the metal is deformed beneath the glass the printer will try to compensate a non-existing deformation. Also while using Inductive sensors, the detection range needs to be adjusted according to the metal which the sensor senses. They are designed for sensing Iron based metals. So for other metals, the sensing distance needs to be derated. A rough multiplier for sensing distances for various metals are given in brackets -  Steel (1.0), Stainless Steel (0.6 - 1.0), Aluminum (0.30 - 0.45), Brass (0.35 - 0.50), Copper (0.25 - 0.45). For eg: if an 8 mm Inductive sensor is used to sense Aluminum, the sensing distance is actually between 2.4 mm and 3.6 mm. So it would be best to test the sensing distance with the sensor you purchased before installation,​ especially while using 4 mm sensors along with a glass build plate.
  
  
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 ==== open collector(oc) & and internal pull up resistor==== ==== open collector(oc) & and internal pull up resistor====
  
-First of all, why do we need a NPN for the Anet-board? The input on the Anet-board is low-active. That means it is held high at 5v with an internal pullup-resistor and is actively switched down to 0V. That is what a NPN-Sensor does.+First of all, why do we need a NPN for the Anet-board? The input on the Anet-board is low-active. That means it is held high at 5 V with an internal pullup-resistor and is actively switched down to 0 V. That is what a NPN-Sensor does.
  
-If you get an open collector sensor you will have an easier wiring. To know if it is a open collector connect the powersupply ​(12V) to the brown(+) and blue(-) wire. Then take a multimeter and check the voltage between black and blue. If there is none you have an open collector sensor, which can be directly connected to the board.+If you get an open collector sensor you will have an easier wiring. To know if it is a open collector connect the power supply ​(12 V) to the brown(+) and blue(-) wire. Then take a multimeter and check the voltage between black and blue. If there is none you have an open collector sensor, which can be directly connected to the board.
  
-Most Chinese sensors do not have an open collector output (might be the LED-circuit). They have an internal pull up resistor. This is why the black wire is not only high impedance when the sensor is not switched but has any voltage on it. For those you need to add at least one resistor between the black and the blue wire to reduce the voltage to nearly ​5v. (as mentioned above it is not for switching but securing the board. switching is done with 0v). Another way it to put a diode in, which should also prevent from damaging the board with voltage-peaks from the sensor while switching.+Most Chinese sensors do not have an open collector output (might be the LED-circuit). They have an internal pull up resistor. This is why the black wire is not only high impedance when the sensor is not switched but has any voltage on it. For those you need to add at least one resistor between the black and the blue wire to reduce the voltage to nearly ​5 V. (as mentioned above it is not for switching but securing the board. switching is done with 0 V). Another way it to put a diode in, which should also prevent from damaging the board with voltage-peaks from the sensor while switching.
  
 As you can see this topic is not easy to solve. So "​universal"​ way is to put in an optocoupler which is not only working but protects your board from damaging As you can see this topic is not easy to solve. So "​universal"​ way is to put in an optocoupler which is not only working but protects your board from damaging
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 ===== Sensor support ===== ===== Sensor support =====
 ^Description^for Sensor^Printer^link/​comment^offset X^offset Y^ ^Description^for Sensor^Printer^link/​comment^offset X^offset Y^
-|Official Anet|ROKO SN04-N|A8|expensive,​ fragile and collides the heat bed harness and connector|15mm|55mm|| +|Official Anet|ROKO SN04-N|A8|expensive,​ fragile and collides the heat bed harness and connector|15 mm|55 mm|| 
-|Official Anet like|ROKO SN04-N|A8|http://​www.thingiverse.com/​thing:​1751859|15mm|55mm|+|Official Anet like|ROKO SN04-N|A8|http://​www.thingiverse.com/​thing:​1751859|15 mm|55 mm|
 | |ROKO SN04-N|A8|http://​www.thingiverse.com/​thing:​1874774|||| | |ROKO SN04-N|A8|http://​www.thingiverse.com/​thing:​1874774||||
-| |ROKO SN04-N/​XY-08N|A8|https://​www.thingiverse.com/​thing:​2319403|-21mm|-43mm|| +| |ROKO SN04-N/​XY-08N|A8|https://​www.thingiverse.com/​thing:​2319403|-21 mm|-43 mm|| 
-| |**HallON A8**|A8 |[[https://​www.thingiverse.com/​thing:​2838259]]|19mm|42mm|+| |**HallON A8**|A8 |[[https://​www.thingiverse.com/​thing:​2838259]]|19 mm|42 mm|
 | |LJC18A3-H-Z/​BX|A6| [[http://​www.thingiverse.com/​thing:​1785616|A6]]| | | |LJC18A3-H-Z/​BX|A6| [[http://​www.thingiverse.com/​thing:​1785616|A6]]| |
-| |**LJ18A3-8-Z/​BX**|A8|[[http://​www.thingiverse.com/​thing:​1911146]]|65mm|-36mm+| |**LJ18A3-8-Z/​BX**|A8|[[http://​www.thingiverse.com/​thing:​1911146]]|65 mm|-36 mm
-| |**18mm capacitive sensor**|A8|http://​www.thingiverse.com/​thing:​1883473| +| |**18 mm capacitive sensor**|A8|http://​www.thingiverse.com/​thing:​1883473| 
-| |12mm inductive sensor| |http://​www.thingiverse.com/​thing:​1884118|+| |12 mm inductive sensor| |http://​www.thingiverse.com/​thing:​1884118|
  
 The offset in X,Y, and Z are the values defined in the firmware (In Marlin Configuration.h). The value for X and Y can be quite coarse. Z has to be accurate and has to be adjusted quite accurately. This value you can set also via display (Marlin): Menu->​Control->​ Motion->​Z-Offset. Procedure to get this value: The offset in X,Y, and Z are the values defined in the firmware (In Marlin Configuration.h). The value for X and Y can be quite coarse. Z has to be accurate and has to be adjusted quite accurately. This value you can set also via display (Marlin): Menu->​Control->​ Motion->​Z-Offset. Procedure to get this value:
-  - Set a large Z-offset value (i.e. 2mm)+  - Set a large Z-offset value (i.e. 2 mm)
   - Autohome your printer   - Autohome your printer
   - place a sheet of paper beneath the nozzle (make sure it is clean)   - place a sheet of paper beneath the nozzle (make sure it is clean)
 +  - Go into Prepare -> Move Axis and disable Soft Endstops
   - move Z-axis down by steps of 0.1 until it touches the paper.   - move Z-axis down by steps of 0.1 until it touches the paper.
-  - note the Z value (i.e 0.7mm) and subtract it from the initial value (2mm-0.7mm). +  - note the Z value (i.e 0.7 mm) and subtract it from the initial value (2 mm-0.7 mm). 
-  - Set the value as Z-offset (1.3mm)+  - Set the value as Z-offset (1.3 mm)
  
 **HallON** Only Sensor with ready to use predefined firmware, and full project support. ​ **HallON** Only Sensor with ready to use predefined firmware, and full project support. ​
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 ===== Sensor wiring ===== ===== Sensor wiring =====
-The Sensor will be replace the Z switch. You will need a **"JST XPH-3" 3 pin connector**. You might also use the connector of your Z probe if you do not need a 5V power supply as the middle pin is missing.+The Sensor will be replace the Z switch. You will need a **"JST XPH-3" 3 pin connector**. You might also use the connector of your Z probe if you do not need a 5 V power supply as the middle pin is missing.
 The position of the pins on the board is described in the picture: The position of the pins on the board is described in the picture:
  
 {{:​reprap:​anet:​a8:​improvement:​wiring.png?​200|}} {{:​reprap:​anet:​a8:​improvement:​wiring.png?​200|}}
  
-Normally the following color code is used for the sensor Harness :+Normally the following color code is used for the sensor Harness:
  
-  * Black - Signal - for NPN it is 0V=active, high impedance OR supply voltage for inactive+  * Black - Signal - for NPN it is 0 V=active, high impedance OR supply voltage for inactive
   * Brown - Power supply - See sensor for the Voltage*   * Brown - Power supply - See sensor for the Voltage*
-  * Blue  - Ground - 0V+  * Blue  - Ground - 0 V
  
-As most sensors need a voltage larger than the 5V provided by the connector there are two options:+As most sensors need a voltage larger than the 5 V provided by the connector there are a few alternative ​options:
   - Purchase a pre made board:   - Purchase a pre made board:
        * [[https://​www.aliexpress.com/​item/​1-Channel-Optocoupler-Isolation-Module-Input-12V-No-Din-Rail-Holder-PLC-Processors-80KHz-PC817-EL817/​32719957788.html?​spm=a2g0s.9042311.0.0.BpOXWJ|OptoCoupler]]        * [[https://​www.aliexpress.com/​item/​1-Channel-Optocoupler-Isolation-Module-Input-12V-No-Din-Rail-Holder-PLC-Processors-80KHz-PC817-EL817/​32719957788.html?​spm=a2g0s.9042311.0.0.BpOXWJ|OptoCoupler]]
-  - For **5V sensors or for some 6-36V sensors ** use the 5V supply of the connector. Anet and Skynet uses this option for their sensor and it works for the LJ18A3-8-Z/​BX. According to some users the low voltage acceptable for the "​orange"​ sensors. But the this might lead to unreliable readings as it is not designed for this voltage. +  - For **5 V sensors or for some 6-36 V sensors ** use the 5 V supply of the connector. Anet and Skynet3D use this option for their sensor and it works for the LJ18A3-8-Z/​BX. According to some users the low voltage ​is acceptable for the "​orange"​ sensors. But the this might lead to unreliable readings as it is not designed for this voltage. 
-  - If you have an **open collector NPN** sensor (see above) than you may connect the brown wire to the the 12V input of your board and the blue to the ground and finally the black wire to the Z switch (the board should have an internal pull up). +  - If you have an **open collector NPN** sensor (see above) than you may connect the brown wire to the the 12 V input of your board and the blue to the ground and finally the black wire to the Z switch (the board should have an internal pull up). 
-  - If you have an sensor **with an internal pull up resistor**(see above) than you may connect the Brown wire to the the 12V input of your board and the blue to the ground. ​There are the following options: +  - If you have sensor **with an internal pull up resistor**(see above) than you may connect the Brown wire to the the 12 V input of your board and the blue to the ground. ​The following options ​are available
-    - Than add a resistor between the black(signal) and the blue(ground) wire to reduce the resulting voltage from 12V to 5V. The best way is to test it with different resistors and measure the voltage between the signal(black) and ground (blue). Best to start with is 10k, for me it worked with 5k. Increase the resistance if the voltage is to low, decrease if it is to high. When you found the correct resistor you can connect the signal pin (black) to the signal pin of the z-probe plug as shown on the picture. ​+    - Add a resistor between the black(signal) and the blue(ground) wire to reduce the resulting voltage from 12 V to 5 V. The best way is to test it with different resistors and measure the voltage between the signal (black) and ground (blue). Best to start with is 10 kΩ, for me it worked with 5 kΩ. Increase the resistance if the voltage is to low, decrease if it is to high. When you found the correct resistor you can connect the signal pin (black) to the signal pin of the Z-probe plug as shown on the picture. ​
     - The disadvantage of using resistors is that it depends on the power supply voltage and a change of this voltage my damage your printer. This can be avoided by **using a diode**. Assuming a typical NPN normally-open (NO) sensor, connections can be made as in the schematic below (be careful with the polarity of the diode). See Method 3 [[https://​github.com/​thijsk/​Skynet3d/​blob/​master/​Documentation/​diagrams%20and%20images/​Sensor_options.pdf|here]] and [[https://​mertarauh.com/​2017/​01/​18/​dont-trust-the-internet-and-how-to-add-an-inductive-proximity-sensor-to-your-3d-printer-the-proper-and-easiest-way|this post]] for more details.     - The disadvantage of using resistors is that it depends on the power supply voltage and a change of this voltage my damage your printer. This can be avoided by **using a diode**. Assuming a typical NPN normally-open (NO) sensor, connections can be made as in the schematic below (be careful with the polarity of the diode). See Method 3 [[https://​github.com/​thijsk/​Skynet3d/​blob/​master/​Documentation/​diagrams%20and%20images/​Sensor_options.pdf|here]] and [[https://​mertarauh.com/​2017/​01/​18/​dont-trust-the-internet-and-how-to-add-an-inductive-proximity-sensor-to-your-3d-printer-the-proper-and-easiest-way|this post]] for more details.
       * {{:​reprap:​anet:​a8:​improvement:​a8_diode_sensor_12v.png?​400|}}       * {{:​reprap:​anet:​a8:​improvement:​a8_diode_sensor_12v.png?​400|}}
-  - Some tutorials recommend to use **two resistors**. But this is **only for PNP-sensors and for high-active inputs**. In our case this would lead to errors. When the sensor switches to 0V and the Atmega internal pull up is activated there would be about 2,5V on the signal pin which is not recognized as low by the AVR.+  - Some tutorials recommend to use **two resistors**. But this is **only for PNP-sensors and for high-active inputs**. In our case this would lead to errors. When the sensor switches to 0V and the Atmega internal pull up is activated there would be about 2.5 V on the signal pin which is not recognized as low by the AVR.
   - last but not least there is the universal/​safe way for your NPN-Sensor. Putting the optocoupler in:    - last but not least there is the universal/​safe way for your NPN-Sensor. Putting the optocoupler in: 
 {{:​reprap:​anet:​a8:​improvement:​15895108_1220874871337969_6770101747027532263_n.jpg?​600|}} {{:​reprap:​anet:​a8:​improvement:​15895108_1220874871337969_6770101747027532263_n.jpg?​600|}}
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   * [[http://​anet3d.en.made-in-china.com/​custom-detail/​xmQExQndGJUQxmQExQndGJUQ/​The-Firmware-Links-You-May-Need.html|Original Anet firmware]]   * [[http://​anet3d.en.made-in-china.com/​custom-detail/​xmQExQndGJUQxmQExQndGJUQ/​The-Firmware-Links-You-May-Need.html|Original Anet firmware]]
   * [[https://​github.com/​MarlinFirmware/​Marlin|Marlin]] 3D printer firmware.   * [[https://​github.com/​MarlinFirmware/​Marlin|Marlin]] 3D printer firmware.
- <​del>​ * [[reprap:​firmware:​anet:​skynet:​intro|Skynet 3D ]] A marlin-based firmware modified for the Anet A8</​del> ​Skynet ​is obsolete. Use Marlin.+ <​del>​ * [[reprap:​firmware:​anet:​skynet:​intro|Skynet 3D ]] A marlin-based firmware modified for the Anet A8</​del> ​Skynet3D ​is obsolete. Use Marlin.
 ==== Marlin ==== ==== Marlin ====
 Instructions and information can be found here: Instructions and information can be found here:
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 In the case that the sensor is outside of the plate after homing the Y and X axis, use Z safe homing (applies if you are using a sensor support with a negative Y-offset: In the case that the sensor is outside of the plate after homing the Y and X axis, use Z safe homing (applies if you are using a sensor support with a negative Y-offset:
     #define Z_SAFE_HOMING     #define Z_SAFE_HOMING
 +    ​
 +Enable the Soft Endstops option in the menu by uncommenting:​
 +    #define SOFT_ENDSTOPS_MENU_ITEM
  
 ===== Slicer settings ===== ===== Slicer settings =====
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 There are already some configuration files available at [[reprap:​anet:​a8:​slicer:​cura|Cura]] There are already some configuration files available at [[reprap:​anet:​a8:​slicer:​cura|Cura]]
-==== Gcode (only needed if there is no configuration file available for download) ====+==== G-code ​(only needed if there is no configuration file available for download) ====
 === Auto home === === Auto home ===
 Before homing of the Z axis the probe has to be positioned above the heat bed. When the code G28 is sent to the printer this is done automatically. But if "G28 Z" is sent it is not. This is the case for some Cura 2.1 json files. Before homing of the Z axis the probe has to be positioned above the heat bed. When the code G28 is sent to the printer this is done automatically. But if "G28 Z" is sent it is not. This is the case for some Cura 2.1 json files.
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 The G code G29 starts the autolevel procedure. It should be executed after the G28 command The G code G29 starts the autolevel procedure. It should be executed after the G28 command
  
-=== Implementing ​Gcode in CURA 2.1 === +=== Implementing ​G-code ​in CURA 2.1 === 
-The Gcode executed before a print is defined in the json file (see also [[reprap:​anet:​a8:​slicer:​cura|Cura]])+The G-code ​executed before a print is defined in the json file (see also [[reprap:​anet:​a8:​slicer:​cura|Cura]])
 Example: Example:
 <​code>"​default":​ "G21 ;metric values\nG90 ;absolute positioning\nM82 ;set extruder to absolute mode\nM107 ;start with the fan off\nG28;​move X/Y/Z to min endstops\nG29 ;auto level"​\n</​code>​ <​code>"​default":​ "G21 ;metric values\nG90 ;absolute positioning\nM82 ;set extruder to absolute mode\nM107 ;start with the fan off\nG28;​move X/Y/Z to min endstops\nG29 ;auto level"​\n</​code>​
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 ABL can't work miracles. ​ You need to make sure your bed is as level as you can get it by adjusting the corner screws. When you have ABL working well you may like to consider to swap the springs and screws for fixed stands. (Like these, for example [[http://​www.thingiverse.com/​thing:​2165389]].) ABL can't work miracles. ​ You need to make sure your bed is as level as you can get it by adjusting the corner screws. When you have ABL working well you may like to consider to swap the springs and screws for fixed stands. (Like these, for example [[http://​www.thingiverse.com/​thing:​2165389]].)
  
-There'​s no magic number for how flat your bed needs to be, but you probably want any variations to be no more than 1mm across the entire bed.  You can check it manually by laying a straight edge (such as a steel rule) across it, or using your probe by increasing the number of probed points using the instructions under '​Measuring your bed flatness'​.+There'​s no magic number for how flat your bed needs to be, but you probably want any variations to be no more than 1 mm across the entire bed.  You can check it manually by laying a straight edge (such as a steel rule) across it, or using your probe by increasing the number of probed points using the instructions under '​Measuring your bed flatness'​.
  
 ==== Which levelling method are you using? ==== ==== Which levelling method are you using? ====
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 This shows the absolute maximum and minimum measurements the sensor took, the mean (average) of all the measurements,​ the range between the maximum and minimum, and the standard deviation. This shows the absolute maximum and minimum measurements the sensor took, the mean (average) of all the measurements,​ the range between the maximum and minimum, and the standard deviation.
  
-The standard deviation is interesting because it tells us that 68% of all the measurements were within 0.00433mm ​(one standard deviation) of either side of the mean, and 95% of the measurements were within 0.00866 (two standard deviations) of the mean.+The standard deviation is interesting because it tells us that 68 % of all the measurements were within 0.00433 mm (one standard deviation) of either side of the mean, and 95 % of the measurements were within 0.00866 ​mm (two standard deviations) of the mean.
  
-A good probe should consistently give a range in the hundredths of mm, e.g. 0.05mm A very good probe will have a range in the thousandths.+A good probe should consistently give a range in the hundredths of mm, e.g. 0.05 mm. A very good probe will have a range in the thousandths.
  
 More information about standard deviation: More information about standard deviation:
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 ==== Did you let it warm up? ==== ==== Did you let it warm up? ====
-Before setting your Z-offset you need to make sure your printer is up to temperature and you've given it a few minutes for any thermal expansion to occur. ​ Differences in nozzle height of around 0.2mm have been observed between a hot and a cold nozzle. ​ If you set your Z-offset with the nozzle cold, you will most likely find it is too close to the bed when it is hot.+Before setting your Z-offset you need to make sure your printer is up to temperature and you've given it a few minutes for any thermal expansion to occur. ​ Differences in nozzle height of around 0.2 mm have been observed between a hot and a cold nozzle. ​ If you set your Z-offset with the nozzle cold, you will most likely find it is too close to the bed when it is hot.
  
 You should also ensure that the printer has had sufficient time at temperature before starting a print. ​ Ideally give the printer 3-5 minutes after it reaches printing temperatures before you start to print. You should also ensure that the printer has had sufficient time at temperature before starting a print. ​ Ideally give the printer 3-5 minutes after it reaches printing temperatures before you start to print.
  • reprap/anet/a8/improvement/autobedleveling.txt
  • Last modified: 2021/05/09 06:32
  • (external edit)