Jogging axes on the M2 overrides end stops?

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BBID
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Jogging axes on the M2 overrides end stops?

Post by BBID » Thu Jun 15, 2017 3:03 am

Hi all,

I was jogging axes (specifically x and y) on my M2 Rev. E using the LCD. I went a bit too far on each axis and instead of the axis stopping cleanly when hitting the end stop, the printer "crashed" and made a buzzing/grinding noise. :shock: Why does the M2 ignore the end stops when jogging using the LCD? I'm assuming this buzzing/gringing behavior could really damage something on the printer! Thanks for any feedback you can provide...

Hugs
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Re: Jogging axes on the M2 overrides end stops?

Post by Hugs » Thu Jun 15, 2017 2:03 pm

From my reading of the M2 firmware source, the endstops are *only* used for homing and aren't checked during movement commands:

Code: Select all

//===========================================================================
//=============================Mechanical Settings===========================
//===========================================================================

#define ENDSTOPS_ONLY_FOR_HOMING // If defined the endstops will only be used for homing
I haven't traced it through completely but that seems to be why.

If you use software like Repetier host, I think I recall that the software kept track of jogging using its UI and wouldn't allow movements beyond what you set as the build area (EDIT: *if* you homed the axes first). The LCD doesn't have that information so it just happily sends G0/G1 commands regardless of the current head position.

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sthone
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Re: Jogging axes on the M2 overrides end stops?

Post by sthone » Thu Jun 15, 2017 3:00 pm

BBID wrote:I'm assuming this buzzing/gringing behavior could really damage something on the printer!
It won't.... it's just the stepper motors buzzing ... you really can't hurt a stepper motor there's really nothing to strip. Steppers works off electromagnets and the buzzing you here is the stator bouncing between the poles changing polarity because it physical can't turn because of a mechanical resistance of what ever it's trying to turn. (as usual I probably didn't explain that quite right but don't worry about it you can't hurt it.)

BBID
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Re: Jogging axes on the M2 overrides end stops?

Post by BBID » Thu Jun 15, 2017 11:17 pm

Ah, ok, that makes sense. So...the last thing I want to do is monkey with the firmware on my M2. However, I trying to think of a reason Makergear would have jogging commands ignore the end stops and if this is just something you could update in the M2's firmware.

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sthone
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Re: Jogging axes on the M2 overrides end stops?

Post by sthone » Thu Jun 15, 2017 11:45 pm

Honestly maybe its just me but.... the jogging commands are seldom used on any of my printers.

BBID
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Re: Jogging axes on the M2 overrides end stops?

Post by BBID » Sat Jun 17, 2017 5:16 am

I did get this commented on by Makergear. They said they haven't seen any damage caused by overrunning the end stops. If the steppers can't be damaged, the only other possible issue I can see by running the head into the end stops is creating slack in the pulleys from excessive torque, but who knows....I guess only time will tell if this issue can affect the quality of the prints.

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zemlin
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Re: Jogging axes on the M2 overrides end stops?

Post by zemlin » Mon Jun 19, 2017 7:44 pm

BBID wrote:I did get this commented on by Makergear. They said they haven't seen any damage caused by overrunning the end stops. If the steppers can't be damaged, the only other possible issue I can see by running the head into the end stops is creating slack in the pulleys from excessive torque, but who knows....I guess only time will tell if this issue can affect the quality of the prints.
It's not an 'issue' - it's the nature of stepper motors. The motors don't generate enough torque to damage the belts. There will be no impact on the print. Just say OOPS and get on with the business at hand.

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