Independent Z moves

dc42

@dc42 I saw some other post that the plan was to incorporate dual z end stops into the FW, I think that was for 1.19. I found that capability VERY useful in Repetier. Has it been incorporated in 1.21 (I think that is the current version). If so I am not able to find it so please point me in the right direction. Thanks!

Dual Z endstops have been possible with RRF for a long time, see https://duet3d.dozuki.com/Guide/Independent+Z+motors+and+endstop+switches/18?lang=en.

@rgconner said in Independent Z moves:

@dc42

One more silly question from the manual bed leveling assistant link: If you know how much the bed need move to balance out, why not just have the duet issue the commands to the independent steppers to move the bed so it is flat?

My bed often gets out of alignment because of powered off sag. When powered down, the slightest bump or touch of the bed can overcome the friction holding the bed in place.

As @SupraGuy says. https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

wmmc01

Happy New Year! OK, so good progress, I used the really good "Independent Z motors and Endstop Switches" Guide, so I have made the described edits, and connections to the board. I can move the dual Z steppers in absolute mode up and down smoothly. But they do not move if I press Home Z, or even enter G28 Z in the console. I get the response: "G0/G1 Insufficient Axis Homed". I know the end stop switches are working since I can see them "Hit" if I trigger them manually. When I home X and/or Y, once they trigger their homing switches, I get some motion from Z. What should I be checking? Thanks in advanced!

Martin1454

@wmmc01 are your X/Y axis homed when you press home z? normally X and Y should be homed before Z, because you probe the Z-axis at specific X Y coordinates.

dc42

We'll need to see your homez.g file to point out the problem.

wmmc01

@dc42 I have used the dual Z guide to edit this file, so NEW indicates the NEW lines.
; homez.g
; called to home the Z axis
; NEW indicates lines that support dual Z end stops
; generated by RepRapFirmware Configuration Tool v2 on Tue Dec 18 2018 16:44:11 GMT-0500 (Eastern Standard Time)
G91 ; relative positioning
; G1 Z5 F6000 S2 ; lift Z relative to current position Commented out for dual z edits
G1 Z2 F6000 ; NEW Lift Z relatively to current position
; NEW split Z motor control to Z and U
; for it to work we have to show U (param P4) in the UI
M584 Z2 U3 P4 ; NEW
; NEW Move Z and U down until the switches triggers
G1 S1 Z-385 U-385 F1000 ;New edited to 385
; NEW back to combined axes and hidden U
M584 Z2:3 P3 ; NEW
; NEW Back to absolute positioning
G90 ;NEW
; G1 S1 Z-385 F1800 ; OLD move Z down until the endstop is triggered
G92 Z0 ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
G91 ; relative positioning uncommented for NEW
G1 S2 Z5 F100 ; lift Z relative to current position uncommented for NEW
G90 ; absolute positioning uncommented for NEW

wmmc01

@martin1454 Yes

dc42

@wmmc01 said in Independent Z moves:

G1 Z2 F6000 ; NEW Lift Z relatively to current position

You need to either add parameter S2 to that command, or use M584 H0 in config.g to allow axis movement before homing. This is nothing to do with dual Z motors, it has been required since firmware 2.01.

wmmc01

OK, thanks. I copied from this example: https://duet3d.dozuki.com/Guide/Independent+Z+motors+and+endstop+switches/18?lang=en. Not sure if there is a way to correct/edit that. I added a comment regarding this.

Thanks for your help!

dc42

@wmmc01 said in Independent Z moves:

OK, thanks. I copied from this example: https://duet3d.dozuki.com/Guide/Independent+Z+motors+and+endstop+switches/18?lang=en. Not sure if there is a way to correct/edit that. I added a comment regarding this.

Thanks for your help!

Thanks, I can't edit the images because they are hosted by someone else, but I have added two notes in the instructions steps.

wmmc01

New problem. In relative mode I can move Z (Z & U) a distance without an issue. The both move the same amount at the same speed. However when I Home Z, U moves faster and quickly jams. The steppers are identical.
homez.g:
; homez.g
; called to home the Z axis
; NEW indicates lines that support dual Z end stops
; generated by RepRapFirmware Configuration Tool v2 on Tue Dec 18 2018 16:44:11 GMT-0500 (Eastern Standard Time)
G91 ; relative positioning
G1 Z2 S2 F6000 ; NEW Lift Z relatively to current position
; NEW split Z motor control to Z and U
; for it to work we have to show U (param P4) in the UI
M584 Z2 U3 P4 ; NEW
; NEW Move Z and U down until the switches triggers
G1 S1 Z-385 U-385 F1000 ;New edited to 385
; NEW back to combined axes and hidden U
M584 Z2:3 P3 ; NEW
; NEW Back to absolute positioning
G90 ;NEW
; G1 S1 Z-385 F1800 ; OLD move Z down until the endstop is triggered
G92 Z0 ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
G91 ; relative positioning uncommented for NEW
G1 S2 Z5 F100 ; lift Z relative to current position uncommented for NEW
G90 ; absolute positioning uncommented for NEW

DRIVES Portion of config.g:
; Drives
M569 P0 S1 ; Drive 0 goes forwards Y Homes to the Front X Homes to the Right
M569 P1 S0 ; Drive 1 goes BACKWARDS Y Homes to the Front X Homes to the Right
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S1 ; Drive 3 goes forwards
M569 P4 S1 ; NEW Drive 4 goes forwards
;M584 X0 Y1 Z2 E4 ; OLD M584 is next section Apply custom drive mapping
M350 X32 Y32 Z32 U32 E32 I0 ; NEW Configure microstepping without interpolation NEW Added U32
M92 X160.00 Y160.00 Z1600.00 U1600.00 E476.50 ; NEW Set steps per mm NEW Added U1600.00 Changed steps per mm to 1600 was 3200
M566 X900.00 Y900.00 Z12.00 U12.00 E120.00 ; NEW Set maximum instantaneous speed changes (mm/min) NEW Added U
M203 X12000.00 Y12000.00 Z600.00 U600.00 E1200.00 ; NEW Set maximum speeds (mm/min) NEW Added U Changed Max Speed for Z/U to 600 was 6000
M201 X500.00 Y500.00 Z250.00 U250.00 E250.00 ; NEW Set accelerations (mm/s^2) NEW Added U
M906 X800.00 Y800.00 Z800.00 U800.00 E800.00 I30 ; NEW Set motor currents (mA) and motor idle factor in per cent NEW Added U
M84 S30 ; Set idle timeout

;DUAL Z NEW
M584 X0 Y1 Z2:3 U3 E4 P3 ; NEW Line Creates Dual Z by adding U as second Z

dc42

This sounds very much like a bug that I fixed in firmware 2.02. Which firmware version are you using?

wmmc01

I may have figured it out. M584 was previously below all the other Drive info. I moved it to below the last M569, and fixed my steps/mm for Z, and all looks fine now. But I'll keep testing to confirm. Thanks for your help! Really appreciate your quick responses!

BTW FW: 2.02(RTOS) (2018-12-24b1)

Best Regards, Bill