Hi Maslownians !
We need your help to bring the firmware one step closer to higher accuracy and uniform vertical scale accross the workspace. To do so a proposed test firmware is ready for a pull request:
- It implements chain tension and stretch calculations to improve chain length calculation.
- It uses a default sled weight of 25 lbs (11.6 kilo) that you can set with macro $46=value where value =kilo * 9.8 or lbs * 2.2*9.8. That settings would be eventually added to GroundControl.
If enough volunteers report everything is fine, then a pull request will be performed and the community will also enjoy improved standard Maslow Calibration results because:
- the chain stretch compensation reduces the motor distance estimation error
- the sag correction factor is well adjusted with that calibration.
- Rotation radius looks good too.
Although the Standard calibration will be improved, you might want to keep your known values if you trust them to be better.
Why that step?
What are the benefits of making this firmware improvement in such a step?
- More constant vertical scale accross the workspace.
- Users of the triangular link should get better results out of the current GroundControl Calibration scheme.
- When Ground Control will be improved with sled weight setting parameter, it will be easy to set it specifically for their sled.
- With that update, one can also start experimenting with chain tolerance optimisation using the Holey triangular Calibration (instructions here). That without installing another firmware: Just download in a separate folder the HoleyCalibration GroundControl, then you’ll find there the gcode and python scripts.
- (EDIT) It gets users ready for getting a better GroundControl with sled weight setting and the later coming Holey Triangular Calibration.
So I invite you to test that firmware. I did test it and it worked well for me. But we need more feedback to make sure this is ready for a release to be shared with the whole community.
How to test the Firmware beta version
Note 1: If you are a new user, or if you are not familiar with the handlings listed hereafter, then beta testing is not recommended for you. (We would rather avoid supporting users that get in troubles and spend that time fixing / preparing next improvements )
Note 2: This Firmware works with the current Ground Control release.
Make sure you have a copy of your current firmware and GroundControl if you whish to revert after test.
Take screen captures of all GroundControl’s Maslow and advanced settings stored in your arduino.
In a separate folder, get the current GroundControl, then the Beta Test Firmware git repository from here
Use the Arduino IDE to download beta test firmware to your controller.
Quit the IDE
Restart GroundControl and review settings panels and adjust as necessary to restore the same values as you noted with screen captures.
Note: this firmware implements a new EEPROM version table so you may have to re-enter some of your captured maslow settings, but it should not lose the chains length measurements. If it does then you’ll have to reset chains 12 OClock step then extend them again.
Now enter the real motor distance value. No need to cheat anymore to avoid the top middle vertical squash. At least you’ll need to check if there still is some squash (see below)
Quit ground control and restart it to reconnect to the arduino controller and refresh settings and X,Y position identification.
And that is it.
From here you can try and report:
- Did you have to recalibrate chain 12OClock and extend chains?
- Does Ground Control calibration propose values that are close to you current settings?
- Do you get a flat top sled displacement? If not:
- Misadjusted chain tolerances are likely a cause for this,
- That is unless your rotation radius value is wrong (typical tradeoff of the existing calibration). Use the triangulation kit official value
- you may also want to enter a specific sled weight using a macro “$46=value” where value =kilo9.8 or lbs2.2*9.8.
- On one hand you could cheat motor distance a little but…
- You can finally try out chain tolerances optimisation without installing another firmware. Especially if starting from 0 tolerance, this will likely improve you workspace edges location match and remaining top vertical squash issue if any.
Chain tolerance optimisation (advanced users)
I tried that as well. Again, it worked for me and a few others. So read the Holey triangular Calibration calibration instructions. Just download in a separate folder the HoleyCalibration GroundControl, then you’ll find there the gcode and python scripts.
So if you are comfortable with those handlings, please try and report under this topic to support the firmware improvement