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Partial Answer Z_RAISE_BEFORE_HOME

Discussion in 'Troubleshooting' started by joea, Aug 19, 2021.

  1. joea

    joea Active Member

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    If you had not called out the file, I'd have never known. I'll give it a go later on. One set of changes at a time.

    I had already compiled and uploaded ROBOR1PlusV2 after applying the edits I could find/recall for my machine and it did not object, so far.
    One thing I notice now is that the Z position after a "home ALL" from MC displayed on the LCD seems to reflect what is sent via the M565 commands.However, After a power off and on of the printer, the LCD now shows Z +0.000. But it appears that an M565 command will affect the next home all and is persistent at least for that power on session.

    It appears, pending further testing, that M565 is applied BEFORE the "Z-offset" (MC) is applied.
    if it us applied at all, it seems it would be when the slicer does it's magic. I'm off to look at Gcode to attempt to create a simple sequence to test that thought. It will have to be VERY simple, given my current frame of mind.
     
    #21 joea, Aug 21, 2021
    Last edited: Aug 21, 2021
  2. joea

    joea Active Member

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    BTW, it does not seem to matter if the M565 Z value is signed or not, it appears to have the same effect.
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, the M565 is valid until the next G28 or power cycle.
    In my experience the first part of that is BS -- it sticks across homes (G28) but that is what their docs said (sadly they have removed all traces of that documentation since deprecating it).

    It matters if it is negative or positive... more negative is further from the bed, less negative is closer
     
  4. joea

    joea Active Member

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    First part of what? My observation on something else? Sometimes I find it difficult to know which comment you are referring to.

    I get what you are saying about the sign value, All I can say at the moment is that, from appearances, what I see on the LCD anyway, the effect on Z position is the same if signed or unsigned. I've not actually tried any prints using M565, I set that to zero and am hunting for a valid starting point using just Z-offset. That is getting filament to lay down on the bed and then going from there.

    I am at that point now, but think I may have some funky filament, old stuff that has been sitting for some time. It does not extrude perfectly smoothly "into the air" and may be in need of drying. Been telling myself it do/don't need a dedicated dryer for a while now.

    So far, the 1.0.2 (V2) firmware is working. X Y motion seems smoother and ramps up and down in a quieter manner. Probably some setting I, or someone, bonked up at some point, in the previous version. I left everything untouched in this one except steps and LCD.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Bad filament is always a possibility and old filament ... can go bad. If you keep it dehydrated it will be serviceable a lot longer, but still has a shelf-life. Most manufacturers store it in vacuum sealed bags to keep it from absorbing moisture. For PLA, ABS and nylon that is the killer*.

    The documentation that Marlin had for the M565 said that it would only stay in effect from the last G29 to the Next G28... however I can shenanigans on that. For me it seems to hold until a power cycle. Even the autolevling itself sticks until power cycle so if you do a G28; M565; and G29 that lasts until it get powered off.


    *Polycarbonate seems to be less affected by this
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    One way to tell if your filament is 'too wet' -- if it is PLA or ABS it will get brittle and break easily.

    Another way (that works with nylon too) is to watch it extrude. If you get tiny bubbles in the output line of filament, that is caused by steam... from the moisture in the filament.
     
  7. joea

    joea Active Member

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    Ah, good reminder. I do see :"voids", which I guess are bubbles. Some variation in width as well. I guess I need to quit being such a tightwad. Too bad I will probably have to toss a lot of this. Might be worth trying to dry it first.

    I thought I read somewhere that the M565 was unique to the Robo, so I did not think it was a Marlin provided deal.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Robo was one of the few to use autoleveling with Marlin 1.0 in a big way. Then once they had their (Marlin developers) large argument over how things should work (even the negative versus positive offsets used was a sticky subject) and they finally settled on the way they do things now (since 1.19) and ditched the old "ABL" code and you had to pick the style: Mesh, BiLinear, ABL... then with 2.0 they have switched (again) to something called UBL (Universal Bed Leveling) all in an attempt to make it simpler to use.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    MESH was an improvement because you needed to build the mesh once and it was then stored in EPROM and all you needed to do to activate it was use a G29. There was no probing at that point because the mesh was in the flash eprom. The G29 just activated the current mesh.
     
  10. joea

    joea Active Member

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    About that ADHD thing . . . what about raising Z before home?

    This newer version of firmware does not do it either. When I do home all from MC, it just starts moving to 0,0, and does not raise Z until it gets there. Seems "wrong" to me.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I do not know which version they changed that, but if you are using something like OctoPrint you can control this.
    If you are depending on the ending Gcode to do it you can add it there in any slicer, but with OctoPrint you can add it for a home operation (a tad complicated, but described here: https://community.octoprint.org/t/default-ui-gcode/7552/2)
     
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    and if you are not using OctoPi -- I strongly suggest you should. All you need is a raspberry pi, an SD card to put the OctoPi image on and a USB cable to connect to the printer.(well a wall wart power supply for the Pi too)
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    All of my printers (regardless of brand) use this. Only one of the resin printers doesn't but that is because it has something very similar built into the on-board software... so 7 printers with OctoPi -- one without.
     

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