simple homing in ways I can't understand

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simple homing in ways I can't understand

Postby cole » 2016-Nov-Sun-13-Nov

After some repairs to cables during which I ruined my printrbot simple's board, I replaced the control board. While trying to calibrate it, I found that it was doing some pretty weird things. When I home each axis individually, they all go to the corner of the bed, like they should. When I home X and Y, and then, with a separate gcode command, Z, it works as expected. But when I home all 3 axis with one command, it first homes the X and Y axis like normal, then goes almost to the center of the bed, then homes the Z axis. When I send the Y axis to it's zero position, it goes to the opposite side of the bed that it should home at. When I set it to 100, it moves towards the endstop. Here are the current settings:

< 10:16:20 AM: echo:Stored settings retrieved
< 10:16:20 AM: echo:Steps per unit:
< 10:16:20 AM: echo: M92 X80.00 Y80.00 Z2020.00 E96.00
< 10:16:20 AM: echo:Maximum feedrates (mm/s):
< 10:16:20 AM: echo: M203 X125.00 Y125.00 Z5.00 E14.00
< 10:16:20 AM: echo:Maximum Acceleration (mm/s2):
< 10:16:20 AM: echo: M201 X2000 Y2000 Z30 E10000
< 10:16:20 AM: echo:Acceleration: S=acceleration, T=retract acceleration
< 10:16:20 AM: echo: M204 S3000.00 T3000.00
< 10:16:20 AM: echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
< 10:16:20 AM: echo: M205 S0.00 T0.00 B20000 X20.00 Z0.40 E5.00
< 10:16:20 AM: echo:Home offset (mm):
< 10:16:20 AM: echo: M206 X0.00 Y0.00 Z0.00
< 10:16:20 AM: echo:PID settings:
< 10:16:20 AM: echo: M301 P22.20 I1.08 D114.00
< 10:16:20 AM: echo:Min position (mm):
< 10:16:20 AM: echo: M210 X0.00 Y0.00 Z0.00
< 10:16:20 AM: echo:Max position (mm):
< 10:16:20 AM: echo: M211 X230.00 Y100.00 Z254.00
< 10:16:20 AM: echo:Bed probe offset (mm):
< 10:16:20 AM: echo: M212 X20.00 Y0.00 Z0.00

I am pretty lost right now. I think one problem is that I don't fully understand what is meant by home offset. Any help would be wonderful!
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simple homing in ways I can't understand



Re: simple homing in ways I can't understand

Postby RetireeJay » 2016-Nov-Sun-14-Nov

I'm guessing that your Simple is at least a couple of years old. If so, you have fallen victim to the dreaded Y-axis "home" switch swap. For a long time, Printrbot made printers with the Y axis "home" switch located at Y=0. But for some reason, for the last couple of years, they moved the "home" switch to Y = Max.

So now, with the new board (and thus new firmware) your printer thinks that the Y "endstop" switch is located at Y = Max. Perhaps you had to reverse the way the Y motor was plugged into the board, but anyway now your printer "correctly" homes to where your switch is. However, the firmware thinks it's at Y = Max instead of Y = 0.

There's no setting to fix this in your EEPROM listing, so your only options are to either (1) physically move your existing Y "endstop" switch to the other end of Y travel and reverse your Y motor cable end-for-end where it plugs into the board (thus making the printer match the firmware) or else (2) find and upload to your printer a version of the firmware that's appropriate for your "legacy" printrbot - which will probably be available on their web site if you search hard enough. (This would make the firmware match the printer).

If you bought your new card from Printrbot, they should have pre-set it with the correct firmware - so maybe you should contact them directly to see if they'd swap the board for you or give you very detailed instructions on how to replace the firmware.
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