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    Baby step during a long linear move? Baby step other Axes?

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    • jml
      jml last edited by jml

      I read in another post that:
      "The baby stepping is implemented in near real time, normally after the end of the current move or after 0.5 seconds, whichever is greater"

      I'm wondering if that is still the case.

      I was planning on doing the baby stepping during a slow, but long G1 command while the extruder was near the front of the printer. But if the above is true, then the baby stepping won't occur until that long move is finished! Perhaps I will have to program a sine wave or sawtooth pattern instead of a straight line movement.

      dc42 1 Reply Last reply Reply Quote 0
      • jml
        jml last edited by

        And can you do babystepping for other axes? For example, X or Y? Or U or V?

        T3P3Tony 1 Reply Last reply Reply Quote 0
        • T3P3Tony
          T3P3Tony administrators @jml last edited by

          @jml as it is currently implemented it is for Z only:

          https://duet3d.dozuki.com/Wiki/GCode#Section_M290_Baby_stepping

          what use case do you see for another axis?

          www.duet3d.com

          jml NAK_3D 2 Replies Last reply Reply Quote 0
          • jml
            jml @T3P3Tony last edited by

            @t3p3tony in case I have mounted a tool imperfectly.

            1 Reply Last reply Reply Quote 1
            • fma
              fma last edited by

              Or to correct a layer shift... Would be nice!

              Frédéric

              1 Reply Last reply Reply Quote 1
              • dc42
                dc42 administrators @jml last edited by

                @jml said in Baby step during a long linear move? Baby step other Axes?:

                I read in another post that:
                "The baby stepping is implemented in near real time, normally after the end of the current move or after 0.5 seconds, whichever is greater"

                I'm wondering if that is still the case.

                I was planning on doing the baby stepping during a slow, but long G1 command while the extruder was near the front of the printer. But if the above is true, then the baby stepping won't occur until that long move is finished! Perhaps I will have to program a sine wave or sawtooth pattern instead of a straight line movement.

                If you have mesh bed compensation enabled (even with a flat height map) then long straight moves are broken up into segments with lengths approximately equal to the mesh spacing. So in this case, babystepping will take effect faster.

                Duet WiFi hardware designer and firmware engineer
                Please do not ask me for Duet support via PM or email, use the forum
                http://www.escher3d.com, https://miscsolutions.wordpress.com

                jml 1 Reply Last reply Reply Quote 0
                • jml
                  jml @dc42 last edited by

                  @dc42 Thanks, will that work even if I don't have a z-probe? That is, can I just use M557 and have it still work?

                  dc42 1 Reply Last reply Reply Quote 0
                  • dc42
                    dc42 administrators @jml last edited by dc42

                    @jml said in Baby step during a long linear move? Baby step other Axes?:

                    @dc42 Thanks, will that work even if I don't have a z-probe? That is, can I just use M557 and have it still work?

                    You will need to generate a dummy height map file and load it using G29 S2 S1.

                    Duet WiFi hardware designer and firmware engineer
                    Please do not ask me for Duet support via PM or email, use the forum
                    http://www.escher3d.com, https://miscsolutions.wordpress.com

                    jml 1 Reply Last reply Reply Quote 0
                    • jml
                      jml @dc42 last edited by

                      @dc42 Will do, thanks!

                      jml 1 Reply Last reply Reply Quote 0
                      • jml
                        jml @jml last edited by

                        @dc42 Wait, G29 S2 clears the bed height map. I assume you meant G29 S1? First I would make the heightmap.csv file manually.

                        Could I instead use M557 X0:20 Y0:20 S1 to set the mesh spacing to 1mm?

                        1 Reply Last reply Reply Quote 0
                        • dc42
                          dc42 administrators last edited by

                          @jml said in Baby step during a long linear move? Baby step other Axes?:

                          @dc42 Wait, G29 S2 clears the bed height map. I assume you meant G29 S1? First I would make the heightmap.csv file manually.

                          I'm sorry, I did mean S1.

                          Could I instead use M557 X0:20 Y0:20 S1 to set the mesh spacing to 1mm?

                          Instead of what?

                          Duet WiFi hardware designer and firmware engineer
                          Please do not ask me for Duet support via PM or email, use the forum
                          http://www.escher3d.com, https://miscsolutions.wordpress.com

                          jml 1 Reply Last reply Reply Quote 0
                          • jml
                            jml @dc42 last edited by

                            @dc42 Instead of manually creating a dummy .csv height map in excel. I thought when you said "You'll need to generate a dummy height map file" I thought that meant manually create it in Excel or TextEdit. But maybe I mis-assumed!

                            1 Reply Last reply Reply Quote 0
                            • dc42
                              dc42 administrators last edited by

                              If you create a tiny height map, then outside the bounds of that height map it will extrapolate, which is likely to give poor results.

                              Duet WiFi hardware designer and firmware engineer
                              Please do not ask me for Duet support via PM or email, use the forum
                              http://www.escher3d.com, https://miscsolutions.wordpress.com

                              jml 1 Reply Last reply Reply Quote 0
                              • jml
                                jml @dc42 last edited by

                                @dc42 can you clarify whether I should make the height map manually in excel, or if I should make it using M557?

                                Phaedrux 1 Reply Last reply Reply Quote 0
                                • Phaedrux
                                  Phaedrux Moderator @jml last edited by

                                  @jml I think either way you do it, don't make it very small.

                                  Z-Bot CoreXY Build | Thingiverse Profile

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                                  • jml
                                    jml last edited by

                                    Ok I wasn't sure if one way was the wrong way.

                                    1 Reply Last reply Reply Quote 0
                                    • jml
                                      jml last edited by jml

                                      Well I'm not sure if M557 X0:200 Y0:200 S1 will actually create the height map with zeros everywhere, or if there is an extra step after that to populate it with zeros.

                                      1 Reply Last reply Reply Quote 0
                                      • Phaedrux
                                        Phaedrux Moderator last edited by

                                        I think you would have to either run an actual g29 to get it to output a height map you could edit or you'd have to just create your own height map from scratch.

                                        Z-Bot CoreXY Build | Thingiverse Profile

                                        jml 1 Reply Last reply Reply Quote 0
                                        • jml
                                          jml @Phaedrux last edited by

                                          This post is deleted!
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                                          • jml
                                            jml last edited by

                                            Just playing with baby stepping, I have made a short g-code file to move back and forth slowly in the x dimensions (80mm back and forth).

                                            I see that if a G4 command is 5 lines away from the current move, then the baby steps will not execute until after the G4 command has passed.

                                            Normally they will execute after the current move (or "after 500ms is passed, whichever is greater").

                                            I also see that the z axis doesn't just move up right away ... it spreads out the height adjustment across the next move.

                                            This is all without the height map file, so now I will test with the heightmap file (if I can create it successfully. Can someone post their heightmap.csv file so I can base mine off that?

                                            Phaedrux 1 Reply Last reply Reply Quote 0
                                            • Phaedrux
                                              Phaedrux Moderator @jml last edited by Phaedrux

                                              @jml 0_1536647204948_heightmap.csv.txt

                                              M557 X10:280 Y35:270 S15

                                              Z-Bot CoreXY Build | Thingiverse Profile

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                                              • jml
                                                jml last edited by

                                                Adding the heightmap.csv file into the /sys folder didn't change anything - probably I made the file incorrectly or config is wrong.

                                                In config.g I put this near the beginning of the file:
                                                M557 X-100:300 Y-100:300 S1
                                                G29 S1 ; load heightmap.csv

                                                And then in heightmap.csv, I have what I think is correct based off what I see others do online. But it didn't seem to change the behavior at all - I'm still not able to babystep the height during long moves.

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                                                • Phaedrux
                                                  Phaedrux Moderator last edited by

                                                  I'm not sure about using negative values in M557 unless you intend it for areas off the bed? Do you have negative values for your axis minima?

                                                  Z-Bot CoreXY Build | Thingiverse Profile

                                                  jml 1 Reply Last reply Reply Quote 0
                                                  • jml
                                                    jml @Phaedrux last edited by

                                                    @phaedrux No negative values, but I assumed the map could extend beyond the actual print bed boundaries.

                                                    I'll change it to M557 X0:200 Y0:200 S1
                                                    But then in the csv file, should xnum and ynum be 200, or should it be 201? xspacing and yspacing should be 1, and xmin/ymin and xmax/ymax should be 0 and 200 respectively, right?

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                                                    • Phaedrux
                                                      Phaedrux Moderator last edited by Phaedrux

                                                      For it to work it also has to have a grid spacing that generates only as many probe points as it can handle. I think the limit is around 4000 441? So spacing of 1mm is probably way too low. Try 20 or 30mm.

                                                      Z-Bot CoreXY Build | Thingiverse Profile

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