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Setup E3D Chimera/Dual Head on Duet WiFi/RepRapFirmware – and watercooling intro

Some time ago I bought the, at the time, new E3D Chimera+ Watercooled hotend and some extra stuff for it.

(sorry, misplaced photo of unpacked new Chimera+. I’ll see about digging some up!)

I’ve had a bit of issues getting it up and running as the first pump/Reservoir combo I bought from China didn’t work.

A reservoir is just a container where extra water is stored to make sure the system doesn’t run low. It also makes it easier to fill up and maintain, and catch the air/bubbles the bubbles you always have in a new watercooled setup. All of these things can be done without a reservoir, but it makes it a lot easier to get going and easier to maintain and keep a look on waterlevel.

I’ve done a lot of custom watercooling on computers, servers and rack equipment (yes, you can watercool a switch and U1 server), so went into the basement to find some spare equipment.

So, why did I buy a Chinese pump when I allready had a lot of watercooling equiptment the smart reader might ask, and the answer is simply that I figured my pumps were far too powerfull, and yes, they were still too powerfull when I looked at them again, hehe.

My tubings also didn’t match precisely, which I could have worked around and I needed to print some Nylon barbs to work as an adapter from E3Ds bowden solution to the tubes – You can now buy a Water-cooling barbed adapter kit seperately from E3D, which you couldn’t at the time of my purchase… I could do all this, but I still needed a new pump and reservoir.

I could buy a new pump/reservoir combo from China and wait one more month and hope it worked this time…

Or I could buy the Watercooling kit from E3D and get going. This would also make it possible for me to get a look at their new stuff and document it for you in the form of STEP files on GrabCad.

  1. Prelude
  2. Configure RepRapFirmware
  3. Tool Definition
    1. Tool0
    2. Tool1
    3. Tool definition section code
  4. BLTouch offset from Nozzle0
    1. Mesh Grid
    2. The combined section code is like this
  5. Calibrate BLTouch for Z-offset
    1. Find Z-Offset
  6. Define Leadscrew coordinates for Autolevel
      1. How to use it
      2. X coordinates for M671
      3. Y Coordinate for M671
      4. The combined section code is like this
  7. Setup probe coordinates in bed.g

2) Configure RepRapFirmware

Since I’m using my new xBot Chimera+ Watercooled Carriage I need to both setup a new Tool (the second nozzle) which encludes configuring nozzle distance from each other, configure BLTouch placement in regards to my Nozzle, and reset my Z-offset of my BLTouch. Finally I’ll need to redo the coordinates used to do my probing sequce to autolevel my bed.. yes, it’s a lot actually, but taking it one step at a time, and it’s usually not really that hard.

I’ll recommend writing down what you do, if you are like me and work well with having documented what you do and what to do. 
Regardless of the details of your documentation I’ll strongly recommend you do not delete or change existing setup lines, but instead comment them out using ; and create a new line of code, for your new setup.

3) Tool Definition

Lets first add a new tool using M563 for our second nozzle by editing the config.g file. This includes defining which heater and extruder we are going to be using as well as the relative position it has to the first nozzle.

You can name the Tools if you like, which will show up in your web display. I’ve named them Nozzle1 and Nozzle2 respectively.

3.1) Tool0

First tool is Tool 0 (P0), using Extruder 0 (D0) and Heater 1 (H1)
M563 S"Nozzle1" P0 D0 H1 ; Define tool 0
The Tool ofset is defined using G10 and in relation to the origin of the head. I might have used the point between the two nozzles as the origin and defined offset as -10 and +10 on the X axis respectively, but I’m going to be using Nozzle 1 as the origin. This means the offset coordinates for Tool0 are all just 0.
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets

3.2) Tool1

The second nozzle looks like: Tool 1 (P1), using Extruder 1 (D1) and Heater 2 (H2)
M563 S"Nozzle2" P1 D1 H2 ; Define tool
The offset of the second nozzle to the first one is +20 on the X axis, so it will look like this:
G10 P1 X20 Y0 Z0 ; Set tool 1 axis offsets

Note on Fans: If you use the default recommend fan0 as print object cooling fan, you do not need to define a fan.


3.3) Tool definition section code:

; Tools
; P = Tool Nr
; D = Extruder Drive nr
; H = Heater used
M563 S"Nozzle1" P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
M563 S"Nozzle2" P1 D1 H2 ; Define tool 1
G10 P1 X20 Y0 Z0 ; Set tool 1 axis offsets

4) BLTouch offset from Nozzle0

Next up we need to modify the BLTouch position in relation to the Head Origin, which in our case is the first nozzle Tool0.

It is our G31 in the config.g we need to modify. Just leave the Pnnn value as is.

The BLTouch is placed 10mm to the right of the nozzle, which is X10 and 24,26mm in front of the nozzle, which translates to Y-24.26.

Important: Do not use , as normal in metric systems when denoting decimals when defining the gcode.

We are going to set Z offset to 0, and setup this again later to match our new carriage.

This means our (base) G31 looks like this:
G31 P600 X10 Y-24.26 Z0 ; BLTouch offset in relation to Tool0

4.1) Mesh Grid

My Mesh grid is spanning the area from X5,Y5 up to X205,Y165 and probing every 10mm.

Tip: When doing initial setup of the Bed I like to make the probing distance larger, at 20mm to get a rough map to use for manual adjustment.

It means my M557 looks like this:
M557 X5:205 Y5:165 S10 ; Define mesh grid

4.2) The combined section code is like this:

; ## Nozzle Distance from BED - Offset. Higher value, closer to bed.
; Set Z probe trigger value, offset in realtion to nozzle and trigger height adjustment
G31 P600 X10 Y-24.26 Z0 ; Zero offset
M557 X5:205 Y5:165 S10 ; Define mesh grid

5) Calibrate BLTouch for Z-offset

Previously we reset the Z offset using G31 to Z, so it now looks like this:
; ## Nozzle Distance from BED - Offset. Higher value, closer to bed.
; Set Z probe trigger value, offset in realtion to nozzle and trigger height adjustment
G31 P600 X10 Y-24.26 Z0 ; BLTouch offset in relation to Tool0

So, lets go find the proper Z offset:

5.1) Find Z-Offset

  1. Move your sensor to around the middle of the bed. You might even want to make a Macro for this, as it can be usefull for many different cases.
    1. Herer’s a simply macro I named Move to Centerbed, where I home X and Y first:
      G28 XY
      G1 X97 Y120 F4000 ; Move probe to middle of bed
      G28 Z

      We need to home Z before we can continue, or it fails to test properly after firmware 1.21
  2. Move Z untill your nozzle is about 10cm (4 inches) from the bed.
    1. Be ready to click the Emergency Stop in case the probe misbehaves.
    2. Now issue G30 command.
    3. Your BLTouch should now send the Pin Down and your bed should now move up (or nozzle down) untill the BLTouch is triggered.
    4. Hit the Emergency Stop if it didn’t stop or the Pin didn’t drop down.
      1. Go through your deployprobe.g if the Pin didn’t drop down.
  3. With #2 successfull you put your sensor over the middle of the bed and jog Z axis untill your nozzle is touching the bed.
    1. Note: If it refuses to move as it has reached Z-minima you can type in G92 Z5 to tell it, that you are 5mm from Z=0.
  4. Once your nozzle just touched the bed tell the machine we are at Z=0 by issuing:
    G92 Z0
  5. Move Z 10mm away from nozzle
    G1 Z10
  6. Now send G30 S-1 at which point the Pin drops down and the z-axis closes the gap until the BLTouch is triggered.
    1. Z now stops moving and reports the current position without changing anything. Note down the reported value.
  7. You might want to repeat the steps 4-6 a few times to insure consistency. I personally just did it 2 times and later did final adjust by looking at print starts.
  8. Mine reported the following:
    G30 S-1
    Stopped at height 2.4mm
  9. I should insert 2,4mm now, but I’ll detract 0,2 as a safety margin, so I’ll change the Z parameters in the G31 line from 0 to 2.2.
    G31 P600 X10 Y-24.26 Z2.2
    Important: The higher Z value the closer you move the nozzle and bed to each other! It’s better to have a value too low here than too high to avoid the nozzle and bed doing a mating game when homing.
    Important: If you later redo the offset method you should reset the offset to Z0 before starting or it might lead to strange results I’ve found on some occasions.

6) Define Leadscrew coordinates for Autolevel

Since the xBot is using 3x independent motors for our Z axis we need to define the coordinates of the leadscres in relation to the hotend and carriage combination we are using.

This can be a bit harry, but lets start by looking at the xBot Probe Point Helper Drawing I made for this purpose:

The Drawing is not made specifically for the my current xBot Carriage Chimera+ Watercooled but instead lising the dimensions in relation to the rear center manual finger screw. I did it this way to make it easier for people to use their own favorite carriage and hotend solution.

If you want indepth explanation on what I’m doing here, you should read the section on Z-Leadscrew Placement.

6.1) How to use it:

Before starting you should check if your X and Y -maxima coordinates should be changed. I needed to change mine.

Now home your X and Y axes, then move your carriage to the center rear, so BLTouch is lined up to the rear fingerscrew.
The position reads as X97 and I measure the BLTouch to be placed 20mm in front of fingerscrew, meaning my nozzles are actually placed exactly at my Y-Maxima, which is Y215.

6.2) X coordinates for M671

First leadscrew

Front right is placed 153,6mm to the right of the center rear fingerscrew.

Since my center is X97 it amounts to: 97+153,6 = 250,6 for first X coordinate.

Second leadscrew

Front left is placed 153,6mm to the left of center.

So 97-153,6 = -56,6 for second X coordinate.

Third leadscrew

Rear center is placed at the center, so we use 97 for our third X coordinate.

This adds up to the first part of the M671 line, which looks like this so far:
M671 X250.6:-56.6:97

6.3) Y Coordinate for M671

First Leadscrew

Front right is placed 241,1mm in front of the rear center leadscrew, which has the coordinate Y215 since my Nozzles are exactly on top of it and it corresponds to my Y-Maxima

So we take the Y position 215 and detract 241,1, which gives us 215-241,1 = -26,1 for our first Y coordinate

Second Leadscrew

This is placed at the same point on the Y axis as the first leadscrw, so -26,1 for our second Y coordinate

Third Leadscrew

This on is placed 63,5mm further out the Y axis, so:

215 + 63,5 = 278,5 for our third Y coordinate

When adding the Y coordinates to our M671 codeline we get the following:
M671 X250.6:-56.6:97 Y-26.1:-26.1:278.5 S3

The trailing S3 defines maximum correction the leadscrews can do. Default is 1.

6.4) The combined section code is like this:

; Define the X and Y coordinates of the leadscrews.
; Must come after M584, M667 and M669
; S = Maximum correction
; Motor order: Front right, front left, rear center.
; Snn Maximum correction to apply to each leadscrew in mm (optional, default 1.0)
M671 X250.6:-56.6:97 Y-26.1:-26.1:278.5 S3

7) Setup probe coordinates in bed.g for G32

Now its sime to review our bed.g file to see if it’s still valid.

It’s not really crucial where you probe, but you should try to make the probe points as close to each leadscrews as possible.

I set all mine to 2mm from min and max for each axis.. just in case a wire or something got between my carriage and the printer edges.

The Third point needs to take into account how BLTouch is placed 20mm in front of the nozzles, as it wouldn’t be able to probe at Y215 but at best at Y190. I’ve deducted the extra 2mm and landed on Y188.

It might be a bit fiddly to figure it out, as the actual probing coordinates is for the nozzle, so can be confusing when looking at it.

; bed.g
; Called using G32
; Called to perform Autolevel using 3-point probe
M561 ; clear any bed transform
; Made allowances for BLTouch being up to 30mm in front of nozzle. Typical is 27mm+/-
Probe 3-point
M401 ; Deploy probe - deployprobe.g
G30 P0 X207 Y2 Z-9999 ; Front Right
G30 P1 X2 Y2 Z-9999 ; Front Left
G30 P2 X97 Y188 Z-9999 S3 ; Center Rear
M402 ; Retract Probe - retractprobe.g

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BLTouch on Duet WiFi – Configuration and usage

In a previous post we connected our BLTouch sensor physically to the Duet hardware and made some basic configurations as well.

In this post I’ll talk about Probes and Sensors interchangeably and will be using the BLTouch name/model during this post, as that is the one I’m using to test this.

If you want to read a bit of an intro into the differences between autolevel and autocompensation, I wrote a brief section about this in Is this autolevel?

I’ve had some correspondence with a lot of peopleduring the writing of this post and I’ve come to understand that I need to specify the printertype I’m talking about here. My printers, which I’m using as basis for this post are:

  1. A box type printer with fixed XY gantries at the top, working together using the cross method to move a carriage around (like an Ultimaker and my xBot), and using a single z-motor to lift the z-gantry containing the printing bed surface.
  2. My xBot which uses the same XY cross-method, but has 3 seperate Z motors for the Z axis, making it possible to adjust it automatically for true autolevel.

You can still use all information even if you are using a Tower printer (like Prusa etc), but I am going to be referring to the two machine models above throughout this post.

i know very little about Delta machines, so I haven’t written with those machines in mind. Donate a Delta and I’ll write some how-tos on it ?

In this blog-post I’ll try to go through different types of more complete configurations and usage scenarios like:

  • Setup BLTouch in Config.g including defining Mesh Grid to probe using M557.
  • Doing a Mesh Grid Probing sequence using G29
  • Doing a Basic Single Probe using G30 before print start.
  • Doing an Advanced Probing sequence using G32 for Autolevel
  • Setup Slizer Startup Gcode to apply our Mesh Grid to the z-plane after doing the Autolevel Probing.
  1. Using a Probe – Intro and Explained
    1. Auto Bed Compensation drop-down menu walkthrough
    2. Summing up
    3. Usage
  2. Wiring of BLTouch
    1. Probe switch function
    2. PWM Channel for Servo Function
    3. Duex owners
  3. Configuring BLTouch
    1. Create a deployprobe.g and retractprobe.g file
    2. Create a BLTouch Macro Group
  4. Change config.g file
    1. Disable Heater to free up PWM pin
    2. Change Endstop Settings
    3. Define Probe Type
    4. Probe Position
    5. Define Mesh Grid
  5. Total Configuration – Summing up
      1. Config.g changes
      2. New Configuration files
      3. Macros
  6. Calibrate our sensor
    1. Find Z-Offset
    2. Run Mesh Grid Compensation sequence
    3. Save Custom named height maps
  7. Before Printing
    1. Homez.g
    2. Homeall.g
    3. Slizer startup gcode
  8. Multi Z-motor setup using bed.g
    1. Z-leadscrew placements
    2. Define XY Coordinates in config.g
    3. Lets have a look at Homing using a Probe
      1. Slizer Startup and Endcode Examples
      2. Single Z-Motor Machine
      3. Triple Z-Motor Machine
  9. Gcodes used

Using a Probe – Intro and Explained

When adding a Z-probe to your 3D Printer it also means introducing a lot of new terms and it requires a fair bit of setup to do and gcodes to learn to use.

Most printers just have some sort of basic limit switch or maybe a hall or IR -sensor for X, Y and Z. This means a G28 command is enough to home all axes.

When using RepRapFirmware a basic homing sequence requires 4 files to work:

  1. homex.gG28 X
  2. homey.gG28 Y
    1. By issuing: G28 XY you can opt to home X and Y at the same time without Z.
  3. homez.gG28 Z
    1. This command will just home Z without the X and Y axes.
  4. The homeall.g file, which is executed using G28 without specifying any axes afterwards.
    1. This file normally homes all axes your machine might have.

Important: When using a Probe located on Z-min (at your nozzle) and using the most basic/normal probetype with 1x Z-motor using Mesh Grid Compensation the Z-Max endstop will be disabled regardless of any virtual axes you might make to get around this issue! 

I am told that his is not the case when using a Delta type Printer. I am not familiar with Delta configurations.

If you have 2 or more individual Z-motors and have configured Auto Bed Compensation in combination with Mesh Grid Compensation a Z-max endstop is mandatory (is it really?) in order for the Printer to calculate your Z plane accurately.

In order to use a Probe we need to configure it using several new M/Gcodes, which we go through below.

We also get a new arsenal of Gcodes to use during startup, and we can use the various functions in the Auto Bed Compensation drop down menu in our web gui:

Auto Bed Compensation drop-down menu walhthrough

  • The actual button Auto Bed Compensation constitutes a G32 which can only be used if you have 2 or more independent Z-motors.
    • When issuing a G32 command, the bed.g macro file is executed.
    • I don’t know how to make the “Show Probed Points” active?
  • The Disable Bed Compensation is used if you have  Auto Bed Compensation in effect but want to disable it.
    • This can also be done by issuing the M561 command which cancels any bed-plane changes you might have in effect by probing (or anything else).
    • The M561 is also placed first in the bed.g file before doing a new Auto Bed Compensation run.
  • G29 – Run Mesh Grid Compensation – Performs a Mesh Probe which is saved to a heightmap.csv file.
    • By probing the bed you automatically enable it as well.
    • You can use custom names. More on this later.
  • The Show Mesh Grid Heightmap displays the grid performed by G29 graphically.
  • The Load Heightmap from SD Card constitutes a G29 S1 command, which you would typically place in your startupgcode file in your slizer after the probing sequence.
  • Disabled Mesh Grid Compensation equals G29 S2 and stops the printer from using the heightmap.

Before we can run G29 we need to define the mesh to probe, which is done via M557 in our config.g file, which we will further down in this post under Define Mesh Grid.

Summing up

  • We setup and configure our Probe/Sensor in config.g
  • Bed.g is only used if we have 2 or more  independent Z-motors. Tower printers would use this method if the Z motors are using seperate drivers.
  • The bed.g file is used to define probe points using M671 in relation to our Z-motors.
  • The bed.g file is not used if we do not have more than 1 independent Z-motor.
  • You can even have multiple differently named heightmaps to use, if you for instance have different plates for different materials.


  • M561 should always be used before running a new probe sequence of any kind.
  • We use G30 (without parameters) to do to the Z-min probe as defined by G31 in the config.g file
  • If we have 2 or more independent Z-motors we use G32 to do the probing sequence as defined in the bed.g file.
  • Any Heightmaps you want to use is loaded after you have finished your probing sequence.

Wiring of BLTouch

We can seperate the 5 wires of the BLTouch into 2 seperate groups:

  1. Probe switch function:
    The Black (GND) and White (Signal – Z Probe IN) which connects to the Probe Connector on the Duet Controller.

    Note: My “white” wire is red on this photo.
  2. PWM channel for Servo Function.
    The Brown (GND), Red (+5v) and Yellow(PWM) goes either onto  a PWM/Servo connector on a Duex board or we use 3 pins in the 40-pin expansion-connector.
    Note: Regardless of wheter we use a Duex or not, I am going to be using Heater7 in my setup examples, which is PWM channel 5. I do this as it is the last one, so it’s easy to remember and it is physically the PWM channel on Duex which sits closest to the edge of the board.
  3. Here is he complete overview of pins used if you do no have a Duex board.

    1. For Duex owners, the Heater7/PWM5 is the connector you see on the middle left side here and the upper one is the Probe connector on the Duet Controller.

      Note: On the photo I have a resistor installed in the Probe Connector. This is necessary if you are using one of the older BLTouch models without the trace you can cut on the rear of it, to make it run 3.3v logic.
      Note: I had a machine where I thought I had cut the trace, but it wasn’t cut all the way, but it still worked, so you might be able to skip this. Ie mine worked fine even though it was still setup as running 5v logic, which means it was still without correct readings it seemed.

Configuring BLTouch

Now that we have everything hooked up, we need to setup our firmware to be able to use it. This includes creating some files and editing config.g and in some cases also bed.g

Create a Deploy and Retract file

Regardless of setup we need to create a deployprobe.g  and a retractprobe.g file.

  • Deployprobe.g
    M280 P7 S10 I1
  • Retractprobe.g
    M280 P7 S90 I1
    These files are used to execute our probe as needed.

Note: If you use Duex2/5 you do not need the i1 parameter

Create a Levelplate Macro Group

This is not strictly necessary, but really usefull, so go to your Macro area and create a new Directory named BLTouch.

Now we create some macros as shown:

  • Alarm Release + Pin UP
    M280 P7 S160 ; Alarm Release and Push-Pin UP
  • Pin Down
    M280 P7 S10 ; Send PWM channel 7 the s10 (angle) command
  • Pin Up
    M280 P7 S90 ; Send PWM channel 7 the S90 (angle) command
  • Self-Test
    M280 P7 S120 ; Send PWM channel 7 the S10 (angle) command

You might want to create some more macros to quickly run your probe to the center of your bed and each corner etc.

Change config.g file

We need to make some changes in our config.g file in order to make use of our probe.

Please note that some or all of these entries exists in your config.g file alrleady if you used the RepRapFirmware online configurator to create your files.

Disable Heater 7

We use M307 to disable Heater 7 to free up the PWM5 channel for our servo (probe).

I’ve put this down with my oher Heater settings for hotend (M301) and heated bed (M307) in the config.g file.
; BLTouch - Heaters
M307 H7 A-1 C-1 D-1 ; Disable the 7th Heater to free up PWM channel 5 on the Duex board.

Change Endstop Settings

Next up we need to change our Endstop Settings, which is done using M574 gcode

It might look something like this now:
M574 X1 Y2 Z2 S1 ; X home to min. Y and Z home to max. Normally Closed limit switches.
We need to remove the Z2 from this line, and add a new line defining Z as using a probe.

The two new lines are going to look like this:
M574 X1 Y2 S1 ; X home to min. Y home to max. Normally Closed limit switches.
M574 Z1 S2 ; Define Z to use Probe. Home to Min

Define Probe Type

Next up we define our probe type using M558, which is Type 5 in our case:

  • P is probe type
  • H is diveheight, which means how far bed moves down/hotend up, between each probes
  • F is the speed of bed up/down movement. If it’s too slow the Probe pin might hit the bed and cause an error.
  • T is the movement speed between probepoints.
  • The X, Y and Z denotes which axes are used by the probe. X and Y are not used, while Z is.

M558 P5 H5 F500 T4000 X0 Y0 Z1 ; Set Z probe type/mode 5. H=Dive Height. F=Speed the bed moves

Probe Position

Next up we use G31 to define the Sensor’s offset from the nozzle in XY and the Bed in Z.

My carriage with hotend and BLTouch looks like this seen from below.

As you can see, the BLTouch is placed:

  • X is directly in line with the nozzle (X0)
  • Y is -25.3mm in front of nozzle (Y-25.3)
    • Note: if you build my xBot it most likely is further away due to the nature of the Carriage.
  • We start with a Z offset of 0.0mm in regards to actual probe activation and factual distance. This value will be adjust later on, to match our setup.
    • Important: It is important to have Z-offset at 0 before calibrating.
  • P is the value needed to trigger the BLTouch. I’ve seen and tried a lot of different values between 25 and 600 and havn’t noticed any difference. But put a pin on this one in case your probe results are inconsistent.

G31 P25 X0 Y-25.3 Z0.0 ; Z probe trigger value, offset in relation to nozzle. And trigger height adjustment

Define Mesh Grid

Next up we use M557 to define the grid on our printbed we want to probe, in order to create a Mesh the controller can use to compensate for surface inaccuracies.

We start by typing M557 then define start and end points on our X and Y axes. Example below shows how we probe from X5/Y5 to X205/Y165.

The Snn parameter defines the spacing between each probe point, where we have defined it to probe with 20mm interval.

Hint: It can be useful to start out with a big interval like 40mm, to make the probing sequence faster, and it is useful to do some manual leveling based on the probing result.
Afterwards, if you have individually driven motors, you do a fine mest for auto compensation when you can’t manually adjust it any better.

Note: There is a maximum of 400 points available for probing, so making it too fine will result in an error. If you get an error, try raising the Snn parameter.

M557 X5:205 Y5:165 S20 ; Define mesh grid

You could do your Mesh Probe sequence now, but it’s important to calibrate your BLTouch first, by calculating the Z-offset

Total Configuration – Summing up

  • Config.g changes Lets combine all our code snippets and put them in our config.g file at your current Endstop section.
  • M574 X1 Y2 S1 ; X home to min. Y home to max. NC microswitches.
    M574 Z1 S2 ; Define Z to use Probe. Home to Min.
    M558 P5 H5 F500 T4000 X0 Y0 Z1 ; Set Z probe type/mode 5. Not using on XY, but using it on Z.
    G31 P25 X0 Y-25.3 Z0.0 ; Z probe trigger value, offset in relation to nozzle. And trigger height adjustment
  • Disable the Heater PWN channel to free it up for our usage:
    ; BLTouch - Heaters
    M307 H7 A-1 C-1 D-1 ; Disable the 7th Heater to free up PWM channel 5 on the Duex board.
  • New Configuration Files
    Regardless of how your setup looks we also created a deployprobe.g  and a retractprobe.g file.

    • Deployprobe.g
      M280 P7 S10 I1
    • Retractprobe.g
      M280 P7 S90 I1
      These files are used to execute our probe as needed.

Note: If you use Duex2/5 you do not need the i1 parameter

    • Macros
      While not strictly necessary it comes in very handy to have created these:

      • Alarm Release + Pin UP
        M280 P7 S160 I1 ; Alarm Release and Push-Pin UP
      • Pin Down
        M280 P7 S10 I1 ; Send PWM channel 7 the s10 (angle) command
      • Pin Up
        M280 P7 S90 I1 ; Send PWM channel 7 the S90 (angle) command
      • Self-Test
        M280 P7 S120 I1; Send PWM channel 7 the S10 (angle) command
      • It isalso very usefull to creeate macros on various places on your bed. Ie in the front corners, center of bed and center rear and so on, depending on your setup.

Note: If you use Duex2/5 you do not need the i1 parameter

Calibrate our sensor.

Now is the time to define the Z-offset parameter in the G31 command in our config.g which looks like this right now:

G31 P25 X0 Y-25.3 Z0.0

Find Z-offset:

  1. Move your sensor to around the middle of the bed. You might even want to make a Macro for this, as it can be usefull for many different cases.
    1. Herer’s a simply macro I named Move to Centerbed, where I home X and Y first:
      G28 XY
      G1 X100 Y120 F4000 ; Move probe to middle of bed
  2. Move Z untill your nozzle is about 10cm (4 inches) from the bed.
    1. Be ready to click the Emergency Stop in case the probe misbehaves.
    2. Now issue G30 command.
    3. Your BLTouch should now send the Pin Down and your bed should now move up (or nozzle down) untill the BLTouch is triggered.
    4. Hit the Emergency Stop if it didn’t stop or the Pin didn’t drop down.
      1. Go through your deployprobe.g if the Pin didn’t drop down.
  3. With #2 successfull you put your sensor over the middle of the bed and jog Z axis untill your nozzle is touching the bed.
    1. Note: If it refuses to move as it has reached Z-minima you can type in G92 Z5 to tell it, that you are 5mm from Z=0.
  4. Once your nozzle just touched the bed tell the machine we are at Z=0 by issuing:
    G92 Z0
  5. Move Z 10mm away from nozzle
    G1 Z10
  6. Now send G30 S-1 at which point the Pin drops down and the z-axis closes the gap until the BLTouch is triggered. Z now stops moving and reports the current position without changing anything. Note down the reported value.
  7. You might want to repeat the steps 4-6 a few times to insure consistency. I personally just did it 2 times and later did final adjust by looking at print starts.
  8. Mine reported the following:
    G30 S-1
    Stopped at height 0.980 mm
  9. This means I’ll change the Z parameters in the G31 line from 0 to 0.98.
    G31 P25 X0 Y-25.3 Z0.98
    Important: The higher Z value the closer you move the nozzle and bed to each other! It’s better to have a value too low here than too high to avoid the nozzle and bed doing a mating game when homing. 
    Important: If you later redo the offset method you must set the offset to Z0 before starting or it might lead to strange results I’ve found on some occasions.

Run Mesh Grid Compensation sequence

Now that we have all our parameters in place we can run a Mesh Probe Sequence by clicking the “Run Mesh Grid Compensation” via the Drop Down Menu, or just type in G29

This Mesh Grid consists of a lot of X, Y and Z coordinates. It can be very helpfull to use this to do some manual adjustment of the Z plane. Ie, meaning you try to make your printbed as level as possible manually by running some faster rougher sequences, and then use a final high resolution mesh sequence when done.

The first Mesh Probe sequence I ran at 11:23 had a mean error of 0.182 and a deviation of 0.084. In normal words the rear bed was a tad higher than the front, so I gave the center rear screw half a turn and did the sequence again. This time the mean error went down to 0.077 and the deviation also decreased a good deal.

You can hover the mouse over the probe points to see the XYZ coordinates.

By Running the mesh grid compensation sequence by either clicking in the menu or typing G29 it will be saved into the file heightmap.csv and be activated.

Save Custom named height maps

If you use multiple different surfaces as I do, you might want to have several heightmaps on hand.

You can use M374 to save the heightmap with a different name than the default heightmap.csv. Below I’ve saved the heightmap as “bareplate.csv” as this is directly onto the surface of my PEI-Coated aluminium plate.

I’ll be making different files for when I’m using glass for printing Nylon, FlexiPlate for PLA and so on.

In order to use one of our custom named heightmaps we can not just use G29 S1 to load the default map, but instead we use M375 to call up our desired height map:
M375 P"bareplate.csv"

Before Printing

Before we can wrap up our configuration we need to adjust our homeing files to match.


The Gcode G30 is actually enough to deploy the probe and make your Z axis home. I’ve added a line to move the bed to Z=10 after probing like so:

; Homez.g
G30 ; Do a single probe to home our Z axis
G90 ; Make sure we are in absolute mode

G1 Z10 F6000 ; Rapidly move the Z axis to Z=10.

The G30 just probes and set Z to 0. The Offset we configured previously adjust the distance to match.


I’m a bit confused here actually as it seems the machine uses homeall and then issue homez even if we havn’t made references to it in the homeall.g file.

Can anyone shed light on this behaviour?

Slizer startup gcode

In order to actively be using our Mesh and use the Sensor when we print, we need to add some lines to our slizer’s startup gcode

  • Here I’m first homing my X and Y axis.
  • Then clearing any Bed Transform I might have in place, as it would otherwise affect the probing.
  • I’m then moving the probe to be at the middle of the bed. If it oozes, you might want to omit or change this.
  • I’m then issuing the G30 command which brings my Z axis to close the distance between nozzle and bed and do the single probe.
  • Now it’s time to load the heightmap we have created previsouly using our Mesh Grid. It is important this comes after the bed probe.
    • You either use G29 S1 to load the default heightmap.csv or you use the M375 to load a custom heightmap.
    • I’ve loaded my custom heightmap below.
  • Finally I’m moving the Z to 20

G28 XY ;Home XY
M561 ; Clear any bed transform that might be in place
G1 X104.5 Y130 ; Move Probe to middle of bed
G30 ; Do a single probe
M375 P"bareplate.csv" ; Load my custom heightmap. Otherwise use G29 S1
G1 Z20.0 F6000 ; Move Z to 20

Multi Z-motors setup using bed.g

Now we have all the common stuff in place we are ready to look at the functions where we use the bed.g file to define how our individual Z-motors are placed and react when probing.

Note: Remember I’m talking from a Box Printer perspective here, but you can use it just fine for Tower Printers  just keep my references in mind!

In order to use the multi z-motor functione we use he multi-probe gcode G32 when homing Z, which calls on the macrofile bed.g where we have multiple probe points instead of just using the single probe point defined via M557 in our config.g file, using the single-probe command G30.

Z-Leadscrew placements

In order to put in some meaningfull coordinates in bed.g we need to know where our Z-leadscrews are in relation to our probe.

Here we can see the placement of my 3 leadscrews on my xBot printer, in relation ot the fingerscrews on my bed.

I used the rear center screw to pinpoint the exact XY coordinate of the probe in relation to the screws.

The numbers in the red circles are the placement and numbering of my Z-motors, while the square boxes indicates the coordinate and probe sequence of my bed.g file.

  • The bed.g starts by issuing a M561 to clear any bed-plane fitting/transform we might have in place by a previous probing.
  • Next we clear any heightmap we might have in effect as the height map should only be loaded after performing our bed leveling probe sequence.
  • Deploy our probe using M401 which simply call on our deployprobe.g we created earlier.
  • Now we come to the business of defining where we probe our bed. We issue the G30 command 3 times, starting with motor 1 through 3.
  • It is 3 times as I have 3 independent Z motors.
    • Important: It is very important we use same sequence as we will be defining the leadscrews in our config.g (next step) file using M671
  • The S3 we have listed after our third line of G30 is crucial to the function, as it must be equal to the number of probe points/individual leadscrews we are using.
    • The strange Z-9999 is there as a Z value less than -9999 causes the machine to probe at the current point to get Z, rather than using the given value.
    • If an S field is specified (e.g. G30 P2 X100 Y165 Z-9999 S3) the bed plane is computed for compensation and stored which is exactly what we want here!
    • if using a Tower Printer with 2 individual Z motors, you would put S2 after the last line instead.
  • Now that we have probed one time pr leadscrew and set it up for computation we retract our probe using M402, which just calls our retractprobe.g file.

; bed.g
; Called using G32
; Called to perform True Autolevel using 3-point probe
M561 ; clear any bed transform
G29 S2; Clear bed height map

; Probe 3-point
M401 ; Deploy probe - deployprobe.g
G30 P0 X200 Y0 Z-9999 ; Front Right
G30 P1 X0 Y0 Z-9999 ; Front Left
G30 P2 X100 Y165 Z-9999 S3 ; Center Rear
M402 ; Retract Probe - retractprobe.g

Define XY Coordinates in config.g

When using the bed.g file to setup multiply points to probe in relation to the leadscrews, we need to define the XY position of the leadscrews in our config.g file.

These coordinates will be outside our printing area and can as such be much higher and even have negative values.

In order to define these, we use the M671 which I’ve placed above my Endstop section in the config.g file.

We obviously also need to know where our leadscrews are placed in relation to our nozzle, for which I’ve made this drawing:

The coordinates we fill in using M671 are the XY coordinates placed at each of the round numbers, in that order.

Remember you can do this with just 2 individual Z-motors, and as such do not need 3 for full autolevel. Using 2 motors will only level the bed on one axis though, but that is still very neat.

The actual syntax used here is a bit strange as we start by issuing the M671 command, then type the axis in question (X at first), followed by the 3 X coordiantes, seperated by :
Next up we do the same with the Y coordinates and terminated by the optional S3 parameter – not to be confused by the S3 we used above!

I used 3mm in the S as I had some issues with Z sync not working as I wanted it to do. It’s defaulting at S1, so you might do fine without specifying anything for S.

; Define the X and Y coordinates of the leadscrews.
; Must come after M584 (Set drive mapping), M667 (Select CoreXY Mode) and M669 (Choosing Kinematics type)
; Motor order: Front right (1), front left (2), rear center (3).
; Snn Maximum correction in mm to apply to each leadscrew (optional, default 1.0)
M671 X256.6:-53.6:100 Y239.10:239.1:65.50 S3

Lets have a look at Homing using a Probe

Now everything is setup according to our system and we are ready to do an autolevel for the first time.

I’m writing Autolevel as my machine is doing an actual true autolevel. If you use 2 z-motors you “only” level it on one axis where as the Mesh Grid applied after the autolevel is our Auto Compensation.

You need to have homed the X and Y axes before starting, but aside from this, you only really need to type in G32 to do the magic.

It will do a probe sequence on the 3 coordinates defined in the bed.g file and calculate the Z-plane based on these measurements and coordinates of the leadscrews as we just defined in our config.g using M671

If you wonder, my homez.g file just home using a single probe action and rapidly moves the bed down again. I have this in place if I want to redo offset.
; Homez.g
G91 ; Relative Positioning
G90 ; Absolute Positioning
G1 Z20 F4000

Slizer Startup and Endcode Examples

As a rounding up on this post I’m posting my start and end codes on 2 machines:

Single Z-Motor Machine

I’m using Cura as my slizer, so I do not need all the “wait for temperature” gcodes of some other slizers, as these are automatcially in place – except for Chamber Heater, which you must add manually if using such a one.

; Startup Gcode
G91                        ; Relative Positioning
G1 Z-1                     ; Move Z down 1mm
G90                        ; Absolute Positioning
G28 XY                     ; Home XY
M561                       ; Clear any bed transform
G1 X104.5 Y130             ; Move Probe to middle of bed
G30                        ; Do a single probe
M375 P"flexiplate.csv"     ; Load heightmap (you can use G29 S1 instead)
G1 Z20.0 F6000             ; Move Z to 20
G1 X5 Y5                   ; Move Head to front left
G92 E0                     ; Zero Extruder
G1 F200 E15                ; Prime the extruder
G92 E0                     ; Zero Extruder


; End Gcode
G10 P0 R-273.15 S-273.15     ; Turn off Tool0
G10 P1 R-273.15 S-273.15     ; Turn off Tool1
M140 S-273.15                ; Turn off Bed
M106 S0                      ; Object fan off
G1 Z210                      ; Move Z to Z210
G92 E0                       ; Zero Extruder
G1 E-2 F300                  ; Retract 2mm
G92 E0                       ; Zero Extruder
G28 XY                       ; Home XY
M84                          ; All motors Off

Triple Z-Motor Machine

And my startup gcode for my xBot triple Z-motor machine.

; Startup Gcode
G91                      ; Relative Positioning
G1 Z-1                   ; Move Z down 1mm
G90                      ; Absolute Positioning
G28 XY                   ; Home XY
M561                     ; Clear any bed transform
G1 X104.5 Y173           ; Move Probe to middle of bed
G32                      ; Start 3-point probe sequence
M375 P"bareplate.csv"    ; Load heightmap
G1 Z20.0 F6000           ; Move Z to 20
G1 X5 Y5                 ; Move Head to front left
G92 E0                   ; Zero Extruder
G1 F200 E20              ; Prime the extruder
G92 E0                   ; Zero Extruder

My Endcode for xBot

In this one I home it to XY and U. The U is my virtual axis I’ve made for Z in order for it to be able to home to Z max, which I can’t otherwise do.

This doesn’t work with the setup for the single Z-machine. I have not yet had time to see if I can get around this, by using bed.g even though I don’t need it for that one.

; End Gcdoe
G10 P0 R-273.15 S-273.15   ; Turn off Tool0
G10 P1 R-273.15 S-273.15   ; Turn off Tool1
G10 P2 R-273.15 S-273.15   ; Turn off Tool2
M140 S-273.15              ; Turn off Bed
M141 S-273.15              ; Turn off Chamber Heater
M106 S0                    ; Object fan off
G92 E0                     ; Zero Extruder
G1 E-2 F300                ; Retract 2mm
G92 E0                     ; Zero Extruder
G28 XYU                    ; Home XY and U to Z max
M84                        ; All motors Off


Gcodes Used

Here’s a list of (some of) the M and Gcodes introduced in this post:

  • G28
  • G29 – Detailed Z-Probe
  • G30 – Single Z-Probe
  • G31 – Set or Report Current Probe Status
  • G32 – Probe Z and Calculate Z-Plane


  • M280 – Set Servo Position
  • M374 – Save height map (with alternate name)
  • M375 – Load (custom) height map
  • M557 – Set Z Probe point or define probing grid
  • M558 – Set Z Probe Type
  • M561 – Set Identity Transform (Reset any Mesh probes or adjustments in place)
  • M671 – Define positions of Z leadscrews or bed levelling screws
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xBot Medium – Electronics and Electrical parts (BOM cont.)

In this post I’ll continue describing what is needed to actually build the xBot-Medium printer. Last time I talked about the Custom Parts, and this time it will be about the Electronics and Electrical parts.

I’ve set up a xBot-Medium Github Repository where the files can be found for this project. As I havn’t finished it yet, all the files aren’t there, but they will be! Only the .STP files for the Dibond frame pieces and some a few for printed parts are missing, so it’s pretty much complete allready.

This post is going to be about the Electronics and Electrical parts we need for the xBot-Medium 3D Printer. I’ll list the Mechanical parts in a later post.

All “BOM” posts here on my blog are going to be condensed into a BOM in list form on the x-Bot-Medium Github Repository.

Some parts are both electrical and mechancial, like the motors, and such items are added to this post, while the Mechanical parts post are going to be the completely inert like the various pulleys, belts, nuts and such.

This is mostly going to be a list without a whole lot of exlanation to it.

xBot Medium electrical and electronical listing

  1. Duet WiFi
    1. Thermocoupler Daughterboard
  2. Duex5
    1. Consideration if choosing Duex2
  3. PanelDue 5″
  4. BLTouch SMART
  5. Heated Bed
    1. AC Silicone heater 500w
    2. SSR
  6. 3x Z-Motors
  7. XY Motors
  8. Extruder(motors)
  9. Chamber Heater
    1. 3x 30mm fans
  10. 2x 30mm fans for Printed objects
  11. Powersupply
  12. LED – RGB
    1. Manual on-off rocker
  13. Various
    1. Limit switches
      1. Long arm
      2. Short arm
    2. Front USB power out
    3. Rear USB for Controller access
    4. AC Power plug and on/off
    5. GX12 and G16 connectors
  14. Carriage
  15. Hotend
    1. Thermocoupler
    2. Plated Cobber nozzle
    3. 40w Heater Cartridge
  16. Untill next time


Duet Wifi

As the main controller, I’m using the Duet WiFi from duet3d.

Price: inc 20% vat: €162,3

While the price does seem rather high, you should take all the features in consideration.

Best quality of any controller. Simple as that. Both regarding features and quality. There are many safety features build in, like it doesn’t burn if a driver or sensor is accidentially unplugged while power is on, which is the main cause of dead electronics for many people. It doesn’t require active cooling as it get rids of the heat through PCB surface – active cooling is always a good idea though, but it’s not a requirment like pretty much all machines using pololu drivers.

It’s top of the line quality and uses 5x TMC2660, which are the highest end drivers you can get on any controller. They are very powerfull SilentStep Sticks (big brother to TMC2100/TMC2130) and can drive up to 3amp pr driver. Most people end up going out and spend money on silent step sticks anyway, which easily ends up at €50 for a set of those – and you can’t buy TMC2660 pololu sticks.

At some point many people start looking at a remote way to control and monitor the printer, and end up going out to buy a Raspberry Pi, which is another €35.
Regardless of what solution people use they don’t ever get close to the integrated webserver allready in the Duet WiFi. It’s hugely powerfull and very responsive. Has a ton of usefull information, and you even use it to setup the entire printer, so no need to compile firmware on your printer and then transfer using USB.
Since it’s integrated it also talks directly to the controller instead of using USB.
It also provides for real time changes in setup of most settings. Change fans, extrusionrate and LED using sliders etc etc.


From the official Duet3D Features page.

Feature list
From site

The DuetWifi is an advanced 32 bit electronics for the control of 3D printers and other CNC machines. It has the same features as the Duet Ethernet other than providing a WiFi connectivity rather than ethernet, full feature description is available on our wiki, in summary:

  • Powerful 32 Bit Processor
  • Dedicated Wifi module
  • Super quiet TMC2660 stepper drivers, up to 256 microstepping.
  • Dual extruders on the main board, up to 5 more extruders on the expansion board.
  • High Power rating: Each stepper driver is capable of 2.8A motor current, currently limited in software to 2.4A. The bed heater channel is specifically designed for high current (18A).
  • Connect via PC, tablet or smartphone on the same network to the on board web interface.
  • Setup your printer and update the firmware through the web interface.
  • Expandable up to 7 extruders with Firmware support for mixing nozzles and remapping axes to use high power external drivers.
  • Support for the PanelDue: a full colour graphic touch screen

Thermocoupler Daughterboard

Price inc 20% vat: €31

To be honest: Im not a fan of this design (put mildly)! I find it rather cumbersome how it’s stacked like that, and it can easily fall out if mounted upside down.. and thus prone to failure. The small terminals are very unforgiving as well, so can be hard getting a good connection.

As much as I find the price warranted for the Duet WiFi, I do look at these things the opposite way…

But while we supposedly can use 3rd party solutions I havn’t managed to make anything work, or seen anyone making anything work, so if you want to use Thermocouplers (top board below) or PT100 (big lower board) you have to use the official Duet Daughterboards.

If you know of a sure way to make 3rd party boards to work, please let me/us know! Not just a link to the right chip, it must be a complete solution 🙂

Photos from official Duet3D shop.

Usage in build:

1-2x Thermocoupler Daughterboards, price total €31-62 inc 20% vat!

I’m going to use Thermocoupler for my hotend and for the heated bed as they react much faster and are much more accurate than standard Thermistors. It’s also a must for hotend if you want to print over 280c as a thermistor dies at 290c or so. Thermocoupler and PT100 sensors don’t tend to die on you like Thermistors can either, so it’s a one-time purchace.

I’m still a bit undecided as to wheter I want to use a Thermocoupler or a plain Thermistor for temperature sensing in the chamber. It’s really a high price to pay for this, but lets see if I get any sponsoring for the project.

I used to use PT100 before starting to use Duet, but the PT100 daughterboards were much, much more expensive than Thermocoupler boards, so that is the only reason I use Thermocoupler. There is no actual difference in usage. PT100 should be less prone to suffer from interference, but wheter that transfer over in reality is always questionable 🙂


Price: inc 20% vat: €111,6 for Duex5
Price: inc 20% vat: €77,8 for Duex2

The Duet WiFi has 5 drivers, so you might actually do ok with Duex2 if you only want 1-2 Extruders. There used to be other differences, but not anymore.

Driver assignments

  • 1 for X
  • 1 for Y
  • 3 for Z
  • 1-2 extruders. (Can use Duex2)
  • 3-5 extruders. (Need Duex5)

The Duex2/5 boards has the following features:

The Duex2 and Duex5 has the same feature list aside from the first 4 points here, listed as 2/5:

  • 2/5 additional TMC2660 stepper motor drivers with stall notification.
  • 2/5 additional extruder heater outputs.
  • 2/5 servo outputs with 5V power and 5V signal levels, sharing control channels with the heaters, so you can use unused heater channels to drive servos.
  • 2/5 additional endstop inputs with indicator LEDs and 3.3V/5V voltage selection. These are also usable as outputs.
  • 6 additional controlled fan outputs, also usable for driving LEDs etc. The output voltage may be switched between 5V, 12V and VIN.
  • 4 uncommitted general purpose I/O pins.
  • 12V switching regulator, for generating a 12V supply for fans, LEDs etc. when the VIN power is higher than 12V.
  • 5 additional thermistor inputs.
  • Support for 2 more thermocouple or PT100 daughter boards, supporting up to 4 more sensors.
  • Optional 5V external power input for powering servos, fans etc.

Official complete feature list and comparison.

Considerations if choosing Duex2

While researching this I learned the difference between Duex 2 and 5 is only the 4 first points in the above list.

I thought Duex2 would have less fan headers as well. Last year Duex2 also didn’t come with the 12v switching regulator.

It all mean you can pick Duex2 if you don’t plan on using more than 2 extruders, but have to pick Duex5 if you plan on using more than 2 Extruders.

PanelDue 5″

Price: out of stock?
Price Filafarm; inc 19% VAT: 4.3″ €99,89
Price Filafarm; inc 19% VAT: 5″ €109,9

Lets say it as it is: You don’t really need a screen. The Web GUI is just that awesome!

I used my first Duet WiFi printer for over a year without getting around to using the PanelDue I had lying around as the Webinterface is just so super nice and lets face it, these things are really expensive as well.

Price vs performance

It really is a matter of usage preferences as they are stocked full up with features, like:

  • Buying a PanelDue gives you external SD card access (the big SD card type).
  • True serial connection, so full control of the machine (unlike cheap MKS displays which doesn’t really talk to the controller, but only sends commands
    • I mention MKS as someone has worked up an alpha firmware for them, so they might be able to work as standin for PanelDue (using serial)).
  • One awesome thing, which I havn’t seen mentioned elsewhere is how the macro’s you create in Web GUI are transferred to the display as menues and buttons completely automatically. This is awesome, and a super way to stack up on functions: ie i you often do some thing like changing filament, you can make a macro to heatup and retract etc.

Here you can see how I made a few macros to test movement on my previous printer project:

I use the display a lot on my BeTrue3D Printer due to it’s many extruders, but on my normal primary machine I only really use display to check up on temperature at a glance and such.

If that is how you use display as well, you might want to try using the machine without the LCD. Might just use an old phone or tablet, although the response would not be almost instant.


Price Filafarm inc 19% VAT €39.90

We use this sensor to ensure correct distance betwee hotend nozzle and print bed and also to take advantage of our 3-motor Z-axis for complete true autolevel function.

Since the xBot-Medium is 10mm deeper than an Ultimaker 2+ we can now squeese one of these in in front of our hotend.

It’s a combination of a normal limit switch functionality and a servo motor to raise up this switch after engaging, which was a somewhat common solution some years ago. ANTClabs combined these things an came up with the BLTouch.

Lets start by saying: Don’t buy copies. Just don’t. There is a huge difference in quality and you really want these things to work 100%.

If you look around you find a lot of people having problems.. when you dig in, you find that all the people having issues are using copies.

You also want the newest version, called SMART. You can check the difference by the sticker labeled SMART, by the tip of the probe-pin and the BLTouch also needs to have serial number printed on it, which can be verified a



Heated Bed

Price from inc VAT €54-71

I’m using a 5mm thick PEI-Coated Aluminium bed with an AC Silicone heater under.

You can pick from 2 different qualities and several different colors and even get logo or text lasered into the surface.

The price at €54 is the lowest price uses a cast aluminium plate, while you can get a milled plate at €71. I’m honestly not sure what my plates are, as I couldn’t choose quality back then.

Be sure to pick the Ultimaker 2 257x229x5mm under dimensions.

Email the owner to agree on color and price etc, and to be sure the plate comes with holes for fingerscrews… it should as he’s using my drawings for these plates <wink>

I print PLA, ABS+ and PETG on it with great results. I’ve heard people say PETG sticks too hard, but I’ve had no problems with anything.
I do have seperate glass plates I put on top of my bed when I print Nylon (glue on glass). Some PLA don’t want to stick very well to this plate unless I heat it a lot, so sometimes use glass for PLA as well.

AC Silicone heater 500w

Price from Keenovo €40,5

Specifications: 200X240mm 500W 220V build in Thermocouple Type-K sensor.
Link to same version with Thermistor instead of Thermocouple sensor.

As most everything else, there are different levels of quality, and the same goes for Silicone heaters. I’ve come to like the market leader Keenovo heaters and am using one of their heaters for the xBot-Medium printer.

They come with build in wires for the heater itself and wires for Thermistor. I’ve asked them if they can build in Thermocouple instead, which they agreed to do, so now I’m just waiting to recieve my super nice Heaterpad.

These pads comes with high quality 3M tape preapplied to one side.


Price (RobotDigg) €4

SSR10A DC-AC Solid-state Relay

There are many copies of Solid State Relays (SSR) on the market, so make sure to buy from somewhere you trust. I’ve bought SSR from RobotDigg several times, and always recieved good ones.

Make sure you buy one labaled as DC-AC as it is controlled by DC from our Duet and then in turn controll the AC input to the bed. The AMP is really only important if you use a DC-DC SSR – ie if you have dedicated DC powersupply for your bed, then the SSR must be able to handle the amount of amperage you put through it.

3x Z-Motors

Price from RobotDigg: 3x €26,7 = $80
SKU: 17HS3001-280N w Lead Screw: 280mm long, Tr8x8(P2)

Many people are using various couplers, but I really prefer using motors with embedded lead-screws. Seems the Quality Control is much better on these than the loose lead screws we can buy. At least if we don’t go out and pay a lot of money for them.

Regardless though, we need motors with embedded lead-screws to take advantage of our entire Z-distance. If you use a coupler you would sacrifice about the length of the coupler on Z axis height.

These motors comes with a POM nut, but we can really use it as they are too large to fit in there. I could have modified it some I gues, but I also really want to use the anti-backlash nuts instead, which are cheaper to replace in case of wear and tear.

Specifications of the motors

Threaded Rod NEMA17 Stepper body 40mm lenth, 280mm Tr8*8 Leadscrew and POM Nut

The NEMA17 Threaded Rod Stepper Motor has a precision Acme Tr8*8 Leadscrew coming out directly from the nema17 as a Threaded Shaft.

200 steps per revolution (1.8 deg/step)
2 Phase, Bipolar, 4 wires
Rated Voltage 2V DC
Rated Current 1.2A
Phase Resistance: 1.7 Ohm ± 10% (20º C)
Phase inductance: 4.5 mH ± 20% (1kHz 1 V rms)
Holding torque: 0.4 N.m Min.
Motor body length: 40mm

Acme Lead Screw: 280mm long, Tr8x8(P2)
Nut: POM

The Tr8*8(P2) means it is 8mm in diameter and one revolution give a travel distance of 8mm. It has a pitch of 2mm which is the distance between the raised “edges” (leads). It has 4 starts, meaning 4 seperate “raised edges” (starts).

X and Y Motors

Price from 2x €11,9 = €23,8

For X and Y axis I can use high quality 0.9 degree stepper motors, as I made room for motors with a body length of 48mm instead of the normal 40mm length available in an Ultimaker 2

It means I can use the best quality and best suited 0.9 motor I’ve been able to find for the X and Y axes, namely the 17HM19-2004S from

You might ask: Why not just use some smaller 0.9 motor? Lots of those have high holding torque and ok amperage etc etc… good question!

Problem is however, that between the pancake model I use for my extruders and up to this powerfull full size motor, they all have really high Inductance raiting, meaning they are slow!

Additional resources


Price for 17HM08-1204S from (48mm long) €11,9
Price for 17HM08-1204S from (21mm long) €9,9

I’m going to be using 2 different motor types:

  • The same large 48mm size as used for X and Y meant for 2.85/3mm filament, as they do require some extra power.
    • See specifications just above
  • I’m using the panckage nema 17 which is just 21mm long for my normal 1,75mm filament. These are more than strong enough and really a perfect fit.
    • Note: You can use these for 2.85/3mm as well, but have to give them more current than when using them for 1,75mm. Might need to put a heatsink on it as well, which is why I simply opt to use the larger motor for the thicker filament.

This small motor is awesome! Plain and simple.

You might wonder at the small size for an extruder, but by utilizing it’s awesome specifications with it’s 0.9 degree steps and powerfull 11Ncm / 15, / 1,12kg/cm holding torque inserted into my Belted Extruder v4 it’s packing an awesome package that runs smooth, silent and cool!

Specialize brackets for my Belted Extruder v4 to quickly mount and dismount them on the xBot-Medium will be released.

Additional resources

Chamber Heater

Price eBay €4,75

I’ve bought a 200w 24v heater wiht the dimensions: 140 x 32 x 26 mm. I actually bought mine from, but it’s not available anymore.

Be sure to buy a 24v version. I accidentially bought 12v at first. It’s listed on the side of them. The photo below with measurements on it displays a 12v heater.

It’s really just a small heater element so we need some fans to blow the heat up into our Chamber.

So far I’ve just set my heated bed at 140c degrees and waited for the temperature to reach 40-50c before I started printing Nylon and such.

To be honest I don’t generally need a heater, but I wanted to add one, now that i started from scratch. All materials, including PLA and PETG benefits from higher than normal temperature at a stable level, but the inclosed box design of the printer will ensure a temperature of around 40c after printing for a while, even with no lid on it.

I’ve designed a printable fan-duct which is mounted over the hole in the bottom frame part through which the hot air is exhaused through. It needs to be printed in ABS or similar to handle the temperature.
The printed parts are or will be located on the xBot-Medium Github repository and in the Thingiverse Group for xBot-Medium once I’m done with the files.

3x 30mm fans

Price 3x €1,21 = €3,63

I’ve just bought some standard so called 24v 3010 Hotend Cooling Fan for the Chamber heater. 3fans fits snugly on it, so that’s what I did.

2x 30mm fans for Printed objects

Price 2x €2,08 = €4,17

You either need 2x 30mm fans or figure out something else. Yes, it is plenty to cool the stuff you print, so no need for 2x 50mm blower fans.
You could use 2 of the fans listed above, which I’m using for the Chamber Heater, but I’ve decided to try out some “aluminium” fans instead, which are slightly more expensive.

I normally pick 12v fans for this as it’s very hard to find good quality 24v fans, and if you do, they cost way more.

It means I just put them in series:

  1. The 24v power line connects to red wire on one fan
  2. Gnd to the black wire on the other fan.
  3. The unused pin from each fan is connected by a wire or similar.
  4. Voila, you now have your two 12v fan running in series on your 24v system.

Note: not all 12v fans can do this, but most I’ve tried do it 100%.


Price: €60

The price is approximate what you might expect to find a good Powersupply at.

If you don’t plan on using Chamber heater, you can find a good Meanwell 24v 10amperage powersupply at half the above price.

If you do plan on using the Chamber Heater you should look for a 24v 18-20amperage to make sure you have enough juice.

I’m running my primary printer on a 24v 10amp PSU which is passively cooled, ie no fans, and it never even gets temperate, so no need to go overboard.

Better to get good quality with lower amp, than buy crummy 40amp psu.

You need a relatively low profile powersupply. Not much higher than 40mm.

For the xBot-Medium I managed to win an auction for a MeanWell HPR-450-24 powersupply. This translates to 24v 450w 18.8amp

I originally believed it had temperature controlled fan, but what it has is on/off fan that activates at some % load. It’s loud, so I need to figure something out to tame is.

Additional ressources

  • Dimensions: Width 105mm, height 41mm, depth 218mm
  • Datasheet opens pdf


Price for 5m: €11,25

You don’t need RGB and I’ve always just used plain white light, but I recently learned you could use and control these using 3x FAN headers on the Duet/Duex.

I went and bought 5Meters of 24v RGB LED strip. Like normal led strips you can cut these at invertal and so make the lengths you want. 5m is plenty for several different projects.

I bought mine in the EU, so I guess you can get it at half price in China.

Manual on-off rocker

Price less than €1

Manual on/off switch for our front RGB LED light. I just like to have the ability to switch that rocker to turn the off sometimes even though the lights are programably turned on.

I hope I can just use this on the GND to the LED strip, or maybe I need it on the v+ depending on what is shared on the FAN headers, but lets see!

Just look around. It’s often cheaper to buy 2 than 1 and you might get 5 at almost the same price.



Limit switches – long arms

Price for x2 €1,12

We need 2x Limit Switches with long arms for our X and Y axes.

Limit switches – short arm

Price for x3 €1,5

If you use BLTouch sensor you don’t have to install the 3 Limit Switches as endstop at the Z-Max end, but I’ll recommend that you do.

Partly as you can use it as backup system if the sensor fails and you can use them to synchronize the axes as an initial setup sequence.

Considering the price, I see it as a no-brainer to go and install them.

Front USB power out

Price €1,12

I really like having an USB power output in my 3D Printers. It can be used for webcams, powering phone/tablet or, as my favorite, powering my small USB vacumer for cleaning up the 3D Priner interior!

It requires a custom printed part which is available with the rest on the xBot-Medium Github Repository.

This video does not show the xBot-Medium, but is a video from my youtube channel showing my current primary machine.

You could also install the USB adapter intended for the rear side in this spot instead, if you’d rather go that route. I have not yet made any adapter for this option.

Rear USB for Controller access

Price €1,79

Since we have our Duet WiFi complete enclosed under our frame we need some sort of extensions to make it possible to connect to the controller via USB in case of various update and maintenance.

It’s called an USB 2.0 B Female Socket Panel Mount To Micro 5 Pin USB Male – Cable 50cm

You can route this to the front USB port instead if you like. I just havn’t made an adapter for this yet, but it should be a simple matter.


AC Power plug and on/off

Price €1,12

You can get them in a variety of models. I vastly prefer this model with build in fuse as it removes the need for an inline fuse between the power plug inlet and the internal powersupply.

You can get them with and without light and with different colors for the rocker. The cheapest model is without light and black rocker, while the red-rocker with light is a very close second.

Be sure to wire it correctly, so it’s the live wire connection going through the fuse.

GX12 and G16 connectors

Prices at around €1 each – so totalling at around €7

If you can wait for it, then order from china, as they cost a fraction of the cost. Not just a bit cheaper, but like 1/10 price sometimes!

  • 4x GX12-4
    • We can mount 4 external extruders, each of which takes a GX12-4 pin connector.
  • 1x GX16 8pin
    • We need a GX16 8-pin for our Carriage for Hotend Heater (2p), Heatsink Fan (2p), Object fan (2p), Sensor (2p).
  • 1x GX16 5pin
    • We are using a seperate GX16 5-pin for our BLTouch sensor.
  • 1x GX16 4pin
    • We need a single GX16 4-pin to hook up our heated bed: Heater (2p) and Sensor (2p)


This is just a word used to describe the combined collection of objects driving around along with the Hotend. Ie, the mechanisms themselves, fasteners, extra fans and sensors and so on.

We allready talked about the BLTouch, which is definently a part of the Carriage.
We also went over the 2 fans used to cool our Printed Objects.


Price: E3Dv6 Full Bowden €63,6

I’m going to use genuine Full E3Dv6 1,75mm hotends. I also have a (genuine) Full E3Dv6 3mm I use when printing Flexibles as flexibles in 1,75mm just aren’t viable.

You can use some other hotend if you like, but I prefer the E3Dv6 FULL 1,75mm hotend.

  • The FULL part is important as it is made up of an aluminium heater block, a steel heatbreak and a seperate aluminium heatsink. This model has very tight control over extrusion as the seperate pieces of the heatsink (and different materials) makes for very cleanly defined heat and coldzones. Retraction is normally around 1-1.5mm only, when using bowdenThe bowden tube goes down into the top of the heatsink and into the very top of the steel heatbreak. This means the PTFE materail from the bowden is far away from the hot zone, meaning you can use temperatures way above the LITE version (280 with thermistor – 500 with thermocoupler/pt100 sensor)If you by accident pull up in the bowden while the hotend is hot, nothing happens as the molten plastic can’t get up in the space between bowden and heatbreak. The added friction created by the steel heatbreak is actually a good thing as it makes for very tight filament printing control.
  • The LITE version is not recommended in my world. It is made up of a combined steel heatbreak with embedded heatbreak. This model does not have the same tight control as the FULL as it doesn’t have as effective heatsink and because the PTFE Bowden tube goes all the way down through the heatsink and rest directly on top of the Heater block.If you by accident pull up in the bowden while the hotend is hot, the molten plastic will guarenteed slip up in the space just above the nozzle, inside the heatbreak now freed from PTFE Bowden tube. It means you (most likely / often) have to take it all apart to clean it up, to get it working again!It does not have as tight control and while the FULL only requires 1-1.5mm retract, this LITE version takes 6mm! This long retract is required as it does not have as sharply defined hot and cold ends, so lots of “internal stringing” is going on, which in turn needs to be pushed out of the hotend after each retract = not as clean print. They still print better than most other hotends, don’t get me wrong, but not compared to the FULL!

The price includes lots of parts. You can view all under what’s in the box, from where I’ve taken below photos.

Some parts to mention: The nice Steel heatbreak and aluminium heatbreak with the bowden coupler, full kit with fan shroud, fan, blue silicone caps, thermistor and 24v (30w) heater.

There’s also a single 0,4mm standard Brass nozzle included.


Price €12,5

I’m not a huge fan of Thermistors. Both because they can break, but also because they aren’t that accuracte and I print at higher temperatures than they can go (300+), meaning I’m using a Thermocoupler sensor instead.

E3D has begun selling these, which works fine with the Duet. Duet sell these same Thermocouplers from their store now as well.

It does require you to use a Thermocoupler daughterboard for the Duet, so it’s a pretty big extra expense. You can always add this later.

Plated Copper Nozzle

Price inc. vat €11,75

In my world these things aren’t even optional. I know I know, it’s a big extra expense on top of everything else, and sure, you can wait before buying this.. ok it might be prudent to use the included Brass nozzle untill it’s worn down, but this copper nozzle is just so extremely much nice than the standard Brass nozzles.

They were created for ultra high temperature, but lets take this note from E3D:

In addition to high temperature performance these nozzles have an advanced nickel based plating, considerably reducing the adhesion of plastic to the nozzle. This is great for everyday filaments keeping things clean and shiny, but is particularly important at temperatures above 300°C where a silicone sock can’t be used.

And that non-stick feature is what makes it so awesome. If you have printed PETG you’ll cry tears of joy when trying one of these as stringing is just so much easier to manage – also helps on all other materials.

Don’t go and buy the Copper Heater Block as it will really only make your heating up take much longer and suck out €26,4 of your pocket! .

I honestly beleive them to be not at all relevant when using the Silicone Socks on the standard Aluminium blocks, which are included.

Yes, I own one of these and I really don’t much like it. I have not seen any advantages over normal Heater Block. Right now I’ve mounted it on a hotend I use with the TL-Feeder for 2x filament input as it migt be better when hot and cold filament are constantly changed, but I havn’t tested it much yet.

40/80w Heater Cartridge

Price inc VAT €5,4 for 24v 40w
Price inc VAT €6,73 for 24v 80w

What’s this now? Well, the included 30w heater with blue wires is just really slow and in some instances you will find it having problems keeping up the temperature. Especially when printing semi fast.

I strongly recommend buying the 24v 40w instead for this printer and if you tend to print very fast, you might even opt for the powerfull 24v 80w from

Just remember to do a new PID tuning if you change your heater or sensor.

Untill next time!

Wow, that was one long post! Next post is going to be all about the inert parts of the printer.

Posted on 7 Comments

BLTouch on Duet Wifi & RepRapFirmware

The time has come to setup BLTouch on my system.

I’m going to use Duet WiFi + Duex5, but I’ll post details about using it without the Duex as well.

Since I do use Duex5 and because of other considerations explained in this blog-post, I’ve decided upon not following the pin selection most often mentioend other places. I do however try to explain my reasoning and how you can use it to customize your own setup.

Please let me know if you have comments or inputs. I do take all comments as a positve thing, also potential corrections to my writings 🙂

When I feel I have everything I need, I’ll boil down on this post and use it as a “how-to” for both duet3d wiki and


Physical overview

First a short explanation on how a BLTouch sensor works and what it is: The BLTouch sensor is in the category of Servo sensors, meaning it’s using a mechanical servo mechanism to raise and lower the metal pin to do the testing.

Quote from the maker: ANTCLABS(A&T)

  • BLTouch is an auto leveling sensor for 3D Printers based on open-source.
  • Simple, Smart, High-precision
  • It could work with any kinds of bed materials, such as glasses, woods, metals, and so on.

Probe Connector role

At first the Duet Wifi and RepRapFirmware didn’t support servos, but focused on other sensor types like their own IR-sensor.

It means the description on the WiKi can be a bit confusing for us non-electronical centric people as they talk a lot about using the Probe Sensor, which just doesn’t apply fully to the BLTouch Sensor. (To be honest I get more confused by reading this page, so don’t feel bad if you are like me!)

They have added a BLTouch section now though, which helps a lot. Thumbs up! 🙂

It means we can’t just use all the pins from the Probe connector as the sole connection on the Duet WiFi, but only use 2 of these pins in the Probe Connector, GND and IN, to register the actual signal from the BLTouch. We need to use PWM connector for the other 3 pins from the BLTouch.

The Probe Connector is the one to the right in the photo. Placed next to the LCD connector to the left of it.

The red wire is IN and black wire is GND

Note: You might notice the small 480Ω resistor crimped into the connector here. More on this later.

Using expansion PWM port for Servo

The 3 remaining wires from the BLTouch are there to control the Servo Pin inside the BLTouch.

Since we have a Duex board we are going to use 1 of the 5 ports labeled as “PWM” ports on the board itself, but listed as “Shared with servos” on Duex2/5 main features page.

When looking at the Wiring Diagram, the connectors are labeled as “PWM / Servos“.

Physical Connections

Lets start by looking at the 2 wires for the Probe Connector on the Duet Wifi/Ethernet.

2-Pins for Z signal

We are going to connect the 2 wires labeled Z (white) and GND (black) on the BLTouch and connect to the matching pin on Duet WiFi Probe Connector, as shown in the diagram.

Note: Your wires might be colored differently. Especially if you use a counterfit version like 3DTouch.
My version of the BLTouch is an old Classic version.

5v to 3.3v logic level conversion

The BLTouch is as default configuring using 5v logic. It means we have to make sure we set it up to run as 3.3v logic instead. Don’t worry about not grasping what 3.3v logic means, as it’s really not important to know what it is, only how we hook up our sensor.

If you have an old Classic BLTouch (as I do), you need to either solder or crimp in the included 480Ω (ohm) resistor between the 2 wires for the Probe Connector.

I crimped them into my connector. Mine came with a 480Ω and 10kΩ resistor.

I do not know why the 10kΩ was included.. anyone know?

If you have a new version of BLTouch with serial number, you just need to cut the solder away between 2 solder pads, as shown here:

3-Pins for Servo

The 3 left over wires on the BLTouch are GND (brown), Red (5v) and Orange (control signal)

If you do not own a Duex expansions port and instead use the pins on the Duet Wifi, you connect as shown on this diagram:

You can use a different Heater-pin, just make the necessary adjustment in your configurations.

  • GND ( G, Brown) to pin 2 on Duet WiFi
  • 5v (5v, Red) to pin 1 on Duet WiFi
  • Orange (S, Control signal) to pin 31

Some info on the Duet Wiki where they use pin 8 instead of my 31. They are also using different colors than my BLTouch, so be sure to check on your own model!

Note on below wire colors: I did not have any brown (used black) or orange (used white) cables, so go by the labels near the connectors, or remember my choices.

The difference between Pin 8 and Pin 31, is how Pin8 is assigned Heater 3 and Pin31 is assigned Heater 7. I picked the last available, in case I later wanted to actually use Heater 3 as a heater. I’m never going to use 7 heaters, and Heater 7 connector also made for nicer wiring in my case 🙂

Note: It can be confusing how the numbering on PWM# and E# doesn’t follow each other. Reason for this is, how the Heater numbers (E) starts with E0 and E1 located on main Duet WiFi board, while the PWM ports are either starts with PWM1 or PWM0 is somewhere not known to me.

The above diagram is a small part I made out of the full diagram.

Firmware Configuration

It’s time to configure our firmware in order to use the BLTouch sensor we just connected. There is some good information on the Connecting a Z probe – BLTouch on the Duet3d wiki.

Disable heater

As shown in the warning in the above diagram, the PWM channels are shared with the heaters, so we need to disable the relevant heater.

We are using the PWM_5 connector, which is the 7th Heater.

We disable it using the M307 Gcode command and setting A, D and C to -1 in our Heaters section in Config.g file. Setting them to -1 means they are disabled.

M307 H7 A-1 C-1 D-1

Note: change H7 to whatever heater you need to disable according to how you choose to wire it up.

RepRapFirmware 1.16 and later allow the PID controller for a heater to be disabled by setting the A, C and D parameters to -1. This frees up the corresponding heater control pin for use as a general purpose I/O pin.

Set Servo Position

Now we need to configure the position of our Servo Pin, which we do using the M280 Gcode command.

Deploy Probe

In order to do so, we put the following into our deployprobe.g file. If you do not have this file, you just hit New File in the System Editor where all the other config files are located and create it.

Insert the following into the file, where the P-number corresponds to our H-number above.

M280 P7 S10

S10 is the “angle” the PIN is put in to engage. You can read more and also see a table of most of the expansion pins. When dealing with BLTouch the engaged position is at angle 10.

Note: In the Duet wiki it is listed to include a Invert parameter: I1 at the end as well, but mine doesn’t work when used.

Retract Probe

Next we need to configure how we retract the Servo Pin in the BLTouch. These settings are configured in the retractprobe.g file. Create it the same way as before if you don’t have this file.

M280 P7 S90

Once again, the P-number corresponds to our H-number while S defines the “angle” to put the probe into. When dealing with BLTouch the retracted position is at angle 90.

Note: In the Duet wiki it is listed to include a Invert parameter: I1 at the end as well, but mine doesn’t work when used.

Configure Endstop Section

Set Z-Probe type

Now we need to setup the Probe Type to Type 5 in our Endstop section in the config.g file using the M558 command.

P5 (from RepRapFirmware 1.14) selects a switch (normally closed) for bed probing between In and Gnd pins of the Z-probe connector (Duet 0.8.5 and Duet WiFi).

Settings legend/explanation:

Overview of what the different parameters means and do:

  • P# = Mode/Type of probe – P5 is for bed probing between In and Gnd pins of the Z-probe connector.
  • XYZ# = 1 use probe for this axis. 0 do not use probe for this axis
  • H# = Dive Height of the Servo pin. 5mm is normal for BLTouch
  • F# = Feed Rate mm/min
  • T# = Travel speed to and between probe points (mm/min)

It all means that we insert the follow line for our new Z-Probe, defining the Type and usage settings.

M558 P5 X0 Y0 Z1 H5 F120 T6000 ; Set Z Probe to type Switch or Digital output where Z probe connector is used. Used for z only.;

  • Put it in the Endstop section in config.g file:

Set or Report Current Probe status

Next we need to setup how the Probe behaves, using the G31 command.

Settings legend/explanations

  • Z# = Trigger height. 1.5mm is normal for BlTouch
  • P# = Trigger value. 25-100. Lower it if nothing happens.
  • XY# = Placement of probe relative to your nozzle. Called offset. In mm.

It means we set trigger value to 50 (don’t worry if it means nothing to you), define where the probe is placed in realtion to our nozzle and the trigger height of the Probe Pin.

The Z value is the Z-offset. Used to tune the distance between trigger location and nozzle. Higher offset value and you get the nozzle closer to bed.

G31 P50 X-25 Y38 Z1.5; Set Z probe trigger value, offset and trigger height

  • This line is also placed in the Endstop section in the config.g file.
  • Just place it under the above M558 line.

G32: Probe Z and calculate Z plane

The G32 Gcode Command can be used to define 3 or more probe points. I am only using mine as a Z-min endstop with 1 point, so not going to use this feature for now.


Relevant Gcode commands: