Solved: Setting Z offset for T1

RajaaKahel

@dc42 during the last test:
"I tried again with 50mm Z offset for T1"
Something very strange happened!
First T0 was printing, then the tool changed to T1 (nothing happened, no Z offset) but then when the tool changed back to T0 the bed moved by about 50mm down and went back to continue printing.
After that and before that it didn't move down by 50mm at all.

RajaaKahel

@dc42 T1 is higher than T0. I tried with many gcommands to raise the bed, but they didn't work. I'll try now with G1 R2 Z50

RajaaKahel

@dc42
Ok now the bed is moving down by the value I entered (50mm) Before T1 is activated but it goes back to 0.2mm (the layer height) after T1 is activated. It should go to 50.2mm after T1 is selected and stay there to print. (So now the Z offset is taken into account only during tool change).

Thank you for your time, we are getting closer

; tfree1.g
; called when tool 1 is freed
G1 R2 Z-50
M98 P/macros/parkT1

; tpre1.g
; called before tool 1 is selected

G1 R2 Z50

RajaaKahel

I gave up on this. So much time for nothing. Sometimes it works, sometimes it's not. even tho same commands are used and after rebooting and homing. And the most important is in config.g
The z offset doesn't work. (G10 P1 X0 Y0 Z0.85)

I'll have to redesign the tool mounts to be adjustable mechanically instead or move back to Marlin..

dc42

I'll look into this when I get time. However, E3D uses Duets to control their tool changers and they haven't reported any similar problems.

RajaaKahel

I appreciate that!

RajaaKahel

@dc42
Here's a short video I recorded for you so you can see what actually is happening and maybe it makes it easier to solve the problem.
I don't have any offset commands set anywhere else other than what you see in config.g.
https://www.youtube.com/watch?v=MuGbiBkKNUI

zerspaner_gerd

@rajaakahel
Try this macro, and parts of what happens.

G10 P0 S0 R0
G10 P1 S0 R0
G28
T0
G0 X100 Y100 Z50
G4 S5
M291 P"X100 Y100 Z50 with T0" S2 T0
T1
G4 S5
M291 P"T1 active" S2 T0
G0 X100 Y100 Z50
G4 S5
M291 P"X100 Y100 Z50 with T1" S2 T0

T-1

zerspaner_gerd

Just tested with mine,

You have to do 30 negative (just to test)

At positive 30 he wants to drive 29.8mm minus, but this would require the bed to be driven 29.8mm higher that does not make the Duet.
At T0 Z0 position, it is over

RajaaKahel

@zerspaner_gerd Thank you, I will try with negative value and see if it works

RajaaKahel

@zerspaner_gerd
Thank you sir! That's it! in order to move the bed away from the nozzle, the value must be negative not positive!
; Tools
M563 P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C
M563 P1 D1 H2 ; Define tool 1
G10 P1 X0 Y0 Z-30 ; Set tool 1 axis offsets
G10 P1 R0 S0

dc42

Just to be clear, the XYZ parameters in the G10 commands are the offsets of the tip of the nozzle relative to the head reference point. You can choose the head reference point to be wherever you like, but the G10 offsets, G31 offsets for the Z probe and M208 limits must all be specified in terms of the head reference point.

It's probably safest to choose the head reference point Z position to be the lowest nozzle you have (or slightly lower), so that the Z values in G10 commands for other tools are all positive.