Tinyg crashes at low rpm

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  • January 21, 2016 at 4:18 pm #9288
    patamato
    Member

    The project I’m working on is a machine that dispenses a uv curing gasket material, so I’m using the 4th motor (a axis) set as a normal linear axis to drive a plunger via a thread rod. This works perfectly for the most part, but for some reason, at or below a feedrate on 10mm/min (I need it to be ~8) the machine just crashes. With the setup I have, 10mm/min is equivalent to 7.87 rpm. The crash is identical in behavior to a limit switch shutdown except for the absence of the error message. The really strange part is anything above 10 works perfectly. 10.01 is no problem, but hit 10 and it just immediately stops. my axis settings are as follows:

    [aam] a axis mode 1 [standard]
    [avm] a velocity maximum 20000 deg/min
    [afr] a feedrate maximum 20000 deg/min
    [atn] a travel minimum -1.000 deg
    [atm] a travel maximum -1.000 deg
    [ajm] a jerk maximum 5760 deg/min^3 * 1 million
    [ajh] a jerk homing 11520 deg/min^3 * 1 million
    [ajd] a junction deviation 1.0000 deg (larger is faster)
    [ara] a radius value 1.0000 deg
    [asn] a switch min 1 [0=off,1=homing,2=limit,3=limit+homing]
    [asx] a switch max 0 [0=off,1=homing,2=limit,3=limit+homing]
    [asv] a search velocity 600 deg/min
    [alv] a latch velocity 100 deg/min
    [alb] a latch backoff 5.000 deg
    [azb] a zero backoff 2.000 deg

    Microstepping is set to 8x

    January 21, 2016 at 6:40 pm #9289
    patamato
    Member

    update:

    using coolterm, I get these error messages whenever this occurs
    {“er”:{“fb”:440.20,”st”:31,”msg”:”Move time is NAN”}}
    {“er”:{“fb”:440.20,”st”:28,”msg”:”Failed to get planner buffer”}}

    January 21, 2016 at 9:13 pm #9290
    cmcgrath5035
    Moderator

    We have not seen many questions as yet on A axis operation.

    Can you post your A axis motor parameters as well?
    Probably $4 .

    Does your G code convert RPM to an appropriate F= number in degrees?
    You motor parameters may reveal your strategy Do you actually use A homing?

    January 22, 2016 at 2:22 pm #9291
    patamato
    Member

    [4ma] m4 map to axis 3 [0=X,1=Y,2=Z…]
    [4sa] m4 step angle 1.800 deg
    [4tr] m4 travel per revolution 1.2700 mm
    [4mi] m4 microsteps 8 [1,2,4,8]
    [4po] m4 polarity 0 [0=normal,1=reverse]
    [4pm] m4 power management 2 (in cycle)

    The only gcode I’ve run so far on the a axis is G1 test moves, since I have the a axis configured in axis mode 1. I am not using A homing.

    January 22, 2016 at 4:47 pm #9292
    cmcgrath5035
    Moderator

    Give this a read:

    Since you are in standard mode, I believe your $4tr should be 360, unless you have a gear box on the motor. And then you will have to enter moves in degrees, not mm.

    If you want tinyG to figure out the degrees, you probably have to use $4aam=3, radius mode, and properly configure.

    If you are not using homing, then set $asn=0.

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