feed & velocity limits seem to be ignored for G0

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  • May 18, 2014 at 4:44 pm #5920
    JRDM
    Member

    I have these settings (this is directly from the console read-out):
    $zfm = 20 mm/min
    $zfr = 20 mm/min

    But when I do things like G0Z50 (from a Z=0 starting point), the machine tries to go way too fast for that speed limit and the z axis stalls.

    The machine is set to mm units

    The reason zvm and zfr are set so low is that I keep trying to reduce them and it doesn’t make any difference. The actual speed limit for that axis is above 800 mm/min

    I’ve tried resetting, hoping it would re-load the parameters, but there isn’t any difference in behavior.

    May 18, 2014 at 8:11 pm #5921
    cmcgrath5035
    Moderator

    This sounds like it will be an Alden item (he is traveling) but a couple questions to help him diagnose:

    You said:”….The actual speed limit for that axis is above 800 mm/min”,
    Do you mean that the physical machine can do this, or there is some other setting that says 800 mm/min is OK?

    Does your Z axis seem to be following your 20 mm/min setting when you use a G1 move, e.g. G1Z50 ?
    I’ll assume you have an F xxx (xxx> 20) set already.

    May 18, 2014 at 10:00 pm #5922
    JRDM
    Member

    OK, sorry for the confusion. The Z axis is capable of running 800mm/min without issues.

    And G1 also seems to ignore the set speed limit, so I can say g1 z100 f800 and it would run at 800 mm/min rather than 20mm/min.

    • This reply was modified 10 years, 6 months ago by JRDM.
    May 19, 2014 at 6:28 am #5924
    cmcgrath5035
    Moderator

    Thanks for clarification.

    Interesting, I don’t recall this behavior on G1 moves last I ran my machine (ShapeOkO2) a couple weeks back.

    Can you report what Hardware version of tinyG you have, what FW build is loaded, and what tgFX (I assume that is what you meant by ‘console’) build you are running.

    For example, my tinyG V7 is currently loaded with FW build 412.01, and I am running tgFX build 3256, found here:

    May 19, 2014 at 9:41 am #5925
    JRDM
    Member

    Board is v8
    fv=0.97
    fb=412.01

    I am controlling the board through a serial terminal program (which I mistakenly called a console).

    • This reply was modified 10 years, 6 months ago by JRDM.
    May 19, 2014 at 5:31 pm #5927
    JRDM
    Member

    I just tried running tgFX, but it claimed it couldn’t find my TinyG and asked if I wanted to install new firmware. I’m not enthused by that, as my firmware is supposed to be up to date for that version (412.01) and the fact that it will blow away all my parameters. The older versions of the tgFX don’t find my TinyG either.

    I am using CoolTerm right now.

    May 19, 2014 at 6:01 pm #5928
    dataway
    Member

    JRDM – I experience the same thing with my tinyG in that tgFX does not find my tinyG and I have to cut power to it to reset it and then tgFX finds it ok after that and I do not loose any parameters.

    May 19, 2014 at 6:28 pm #5930
    JRDM
    Member

    OK, I tried cutting power, doing a rescan & connect, as well as reset & connect. tgFX is still not connecting to my TinyG.

    May 19, 2014 at 9:19 pm #5931
    alden
    Member

    The G0 maximum rate is set by the velocity max. So for Z it’s $zvm=xxxx.

    If the machine is going too fast it may also be your motor parameters and other settings. Are you sure the motors steps, travel per revolution and other settings are correct?

    Does the machine also move too fast on G1 moves?

    There’s some useful information in the wiki: https://github.com/synthetos/TinyG/wiki/TinyG-Tuning

    May 19, 2014 at 10:37 pm #5933
    JRDM
    Member

    I’ll check again tomorrow, but I entered all the information from here:
    https://github.com/synthetos/TinyG/wiki/TinyG-Shapeoko-Setup

    My machine is a Shapeoko 2.

    And I realized I had a typo in my first post, it is zvm not zfm.

    I kept dialing down my zvm and zfr until they were below 1

    When I set a g1 move, it works fine and it looks like it moves the correct speed when I enter something like “g1 z30 f750” at the serial terminal.

    I think I have my travel per rev, step angle, etc correct, but as I said, I’ll check again.

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