Movement Issues After Homing

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  • December 11, 2014 at 11:38 am #7150
    emperorcow
    Member

    So I just updated my tinyg (hardware version 7) to Edge 438.02 and changed my switches from NO to NC. I’ve been having an issue with homing I haven’t been able to figure out.

    For reference, I have an original shapeoko that I’ve upgraded over the last year and a half. The tinyg is connected to 4 steppers (1 Z, 1 X, 2 Y) wired separately to the controller. I have four NC switches wired to the X and Y min and max on the controller for limit and homing. Just in case, I’ve attached my current configuration at https://dl.dropboxusercontent.com/u/11998634/tinyg.txt. Also note that I’ve turned off the limit switches for testing this issue, I thought it might be noise but that hasn’t helped.

    As far as toolchain, I have a Raspberry Pi mounted to the shelf I build for the mill and have recently been using ChiliPeppr with SPJS on the Pi. For testing of this issue, I’m simply connecting to the USB tty device with plink and GNU screen to limit potential variables.

    The issue I’m having is that when the I use the configuration above and issue a G28.2 Y0 to test homing, the carriage moves until engaging the homing switch, and then simply stops, never performing a backoff. From there, if I issue a G0 Y1 (in either mm or inch mode) the Y axis will move approximately 21 inches into the positive and the log will report that Y is sitting at approximately Y1000. I am at work right now, but will try and get a log issuing the command later. To further complicate the mystery and confusion, if I change $st to NO the system will perform a backoff when issuing a G28.2. However, I have tested each of the switches with my multimeter, they are most certainly NC.

    Can anyone think of any issues or things I might try or additional data that might help? Thanks!

    December 12, 2014 at 5:46 am #7151
    JuKu
    Member

    Double check that your min switch goes to min and max to max, and not vice versa. It is some time ago so my memories a vague, but I remember mine behave something like that before I fixed this.

    December 12, 2014 at 5:33 pm #7157
    emperorcow
    Member

    Got a chance to gather some further information on this. It looks like when I issue G28.2 y0 the ypos quickly jumps from the 0 it obtained at boot to -500. This is why, when I issue a G0 y0 immediately after the homing process, it jumps so far. Not sure why homing would so quickly jump the axis location, but this happens in both the X and Y. Here is a log from my tinyg: 

    {"r":{"fv":0.970,"fb":438.02,"hp":1,"hv":8,"id":"9H3906-QCS"},"f":[1,0,0,991]}
tinyg [mm] ok>
qr:32, qi:1, qo:1
g28.2 y0
tinyg [mm] ok>
posx:0.000,posy:0.000,posz:0.000,posa:0.000,feed:0.00,vel:0.00,unit:1,coor:0,dist:1,frmo:1,stat:9
qr:32, qi:1, qo:1
qr:31, qi:1, qo:0
posy:-0.631,feed:1000.00,vel:2.21
posy:-510.000,feed:0.00,vel:0.00,coor:1,dist:0,stat:3

    I should note this happens almost immediately. I checked the wiring and it appears to be correct, but I will pull out my multimeter later tonight or this weekend to be absolutely sure things are wired properly. Thanks for the suggestion!

    December 12, 2014 at 6:04 pm #7158
    cmcgrath5035
    Moderator

    Please clarify:

    g28.2 y0
    tinyg [mm] ok>
    posx:0.000,posy:0.000,posz:0.000,posa:0.000,feed:0.00,vel:0.00,unit:1,coor:0,dist:1,frmo:1,stat:9
    qr:32, qi:1, qo:1
    qr:31, qi:1, qo:0
    —> Is there any actual movement here, or just these position updates? <–
    posy:-0.631,feed:1000.00,vel:2.21
    posy:-510.000,feed:0.00,vel:0.00,coor:1,dist:0,stat:3
    —> <–

    • This reply was modified 9 years, 11 months ago by cmcgrath5035.
    December 12, 2014 at 6:45 pm #7164
    emperorcow
    Member

    There is a tiny bit of movement on the axis, maybe approximately 1 mm or so before the position goes from -.061 to -500.

    December 13, 2014 at 10:37 am #7166
    emperorcow
    Member

    So I double checked this morning, all of the limit switches are wired up in the proper order. Thanks again for the suggestion!

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