MaslowCNC/GroundControl

Enhancement

Opened this issue · 21 comments

Hi Bar,
I could not see how to lodge an enhancement rather than an issue, i think this selected enhancement, the following is Enhancement and may be achieved by G-Codes or another question:

Manual set / adjust of the chain lengths / home position to calibrate the 'centre' of the cutting area, this could also be extended to the 'corners' so you can set your calibration rectangle, or derive it from there.

Alternate, the ability to run 'calibration' sub-steps as well, you can sorta do this via start, then skip....

You did it perfectly. I just needed to add the enhancement label (for some reason Git Hub won't let anyone else add labels 🙄 )

The good news is if I'm understanding right this feature is already in place although a little hidden.

You can choose how much chain is extended during the "extend chains" step in the advanced settings menu:

image

That setting will adjust how much chain is extended. The "Center" position is computed automatically from the distance between the motors and the vertical height found in the calibration process along with the bed size settings here:

image

Are those the features needed, or is there more functionality also?

Thanks 😀

I added the "question" tag and we'll close it once we've got you a good answer.

Which step in the calibration process are you looking to do without skipping? Is it the extend the chains step? If so you can run that one by clicking Actions -> Set chain lengths automatic

chain length measure out to set length	-	ok, NB: it did wind the one chain backward however could be picked up and place in ‘right’ direction

The calibration steps, when done in sequence, track the amount of chain extended since the sprockets were zeroed. When the motor separation has been measured, and the end of the chain lifted free but the middle of the chain still engaged on its sprocket, the next step will run the chain 'backward' until 1650mm of chain remains beyond that sprocket. The other sprocket will turn to extend 1650mm of chain.
That same chain calibration can be run alone and then both sprockets will turn as expected to move the chain ends.
A tip, once both chains have come to rest during the chain calibration, but before clicking 'Move to Center' or 'Next', mark the links on the top of the sprockets with some paint. These 'king links' are at a set point 1650mm from the end. Then go ahead and click the 'Next' or 'Return to Center' button to go on with what you were about. The next time you need to calibrate the chains, use the first step of Actions/SetChainLength-Automatic to zero the sprockets, then 'Quit' that without moving the chains. Put the 'king links' on the top tooth of the sprockets and use Actions/Advanced/SetChainLength-Manual to tell the machine that the chains are extended to the set point. If you have a way of supporting/hanging the sled to remove tension from the chains, this manual recalibration can be done without needing to disconnect the sled. Finally, use Actions/ReturnToCenter to move the sled to 0,0.

The issue is that the software has no safe check to see if the motors are a safe distance above the board. You can build a frame with the motors mounted right at the top of the sheet but then when the sled tries to move to the top of the sheet it will cause issues.

I don't want to restrict the way people can build their machines, but would a warning work? That way if someone entered a vertical offset measurement which was too small they would see a pop-up warning that it could cause problems

simple limit check as well?

What about a warning that shows up if the limit check doesn't pass? My concern with a hard limit check which won't let you proceed if the distance is too small is that could lock out some folks from building other designs. For example a hanging plotter with a very light weight pen could operate much closer to the top than a heavy router with weights.

I've added a limit check which spawns a warning popup if the motors are too close to the top of the sheet. You can ignore it, but without clicking "Continue" you won't be able to do anything which seems like a good middle of the road solution to me. Someone building a different type of machine has the option to still use the software, but for most folks the warning will let them know to move the motors up.

image

What do we think?

And the problem isn't that you are too close to the top and the motors may not
have the power, it's that the motors are too close to the workpiece and trying
to go into the top corner will cause the linkage to collide with the sprocket.

I don't think this is true, right @loucksg? The issue you ran into wasn't the sled crashing into one of the motors, it was the tension in the chain being too large at the top of the work area?