I've got a significant reduction in ringing at higher speeds by downsizing so would rather stay with this setup if I can find a way.

Yes, this isnt clear to me. In the Gcode library it has as example of ;

M906 X300 Y500 Z200 E350:350

but then says;

Example: If you have two motors on your Z axis, physically connected to Z and E0 stepper drivers, configured with M584 Z2:3, set M906 Z200, not M906 Z200:200

So maybe your right these E & Z are treated differently. If so that's great because I could run a much bigger stepper on the frame with a higher current. I could run an M906 E500:1200 to drive these for example.

Does this however mean I have to add the other extruder setup lines such as M350, M92, M566, M203, M201?

I guess it would be good to get confirmation that M567 P0 E1:1 will do what I think and set extrusion rates of 100 on both motors and that I'm not barking up the wrong tree!

On the weight issue I am trying to have my cake and eat it, or at least have the best compromise I can find. I'm currently running water cooled to run high enclosure temps so Zesty or similar would cost me that ability. Perhaps I just need another printer for faster prototyping!

Excellent, thank you @chrishamm

As a quick update I now have it 'working', well everything moving as expected at least.

Fundamentally all that confused me was this line in the GCODE library;

If you have two motors on your Z axis, physically connected to Z and E0 stepper drivers, configured with M584 Z2:3, set M906 Z200, not M906 Z200:200

I incorrectly assumed this applied to extruder motors too, where in reality it seems it does not. Not sure who maintains this text but maybe worth adding an extra note in there to make that a little clearer. Although with hindsight the previous included example of M906 X300 Y500 Z200 E350:350 should have been a clue.

Once I went through and added all the other standard motor parameters everything started working. As my extruders are not totally identical (metal BMG clone on HE & OG one on frame) I'm going to calibrate both extruders individually and go for a test print. Will report back after a few prints.

Thanks all for your input

Glad that was simple. Frustrated it took 4 hours of trying all sorts before asking on here!

Don't know how I ended up with that combo but now working. Thanks.

Hi all,

I'm trying to move from a differential IR sensor to a BL Touch and I getting poor reading accuracy.

I'm using a Duet2 Wifi & a DueX5. Firmware Beta3.2

I've followed all the instructions I can find but with the different firmware versions etc find it a little confusing so it's likely I've just made a configuration mistake.

Here is what I think is the relevent config. I'm not using any heaters on the Duex

; BLTouch
M558 P9 C"^zprobe.in" H5 F120 T3000  				; BLTouch connected to Z probe IN pin
M950 S0 C"!duex.pwm1" 						; create servo/gpio 0 on pwm1 on Duex5
M280 P0 S10 							; send control signal to BLTouch through servo/gpio 0
G31	P25 X37.5 Y28.25 Z1					; BLTouch set offset	
M557 X30:260 Y30:520 S20                           	        ; define mesh grid

I'm then sending these through the console but get nothing.

Pin Down - M280 P0 S10
Pin Up - M280 P0 S90
Self-Test - M280 P0 S120

The selftest works on power up so I don't think its the 5V jumper issue highlighted on the troubleshoot page. Photo of my not so neat wiring!

Is there something I'm missing?

Thank you

Excellent, thank you @chrishamm

As a quick update I now have it 'working', well everything moving as expected at least.

Fundamentally all that confused me was this line in the GCODE library;

If you have two motors on your Z axis, physically connected to Z and E0 stepper drivers, configured with M584 Z2:3, set M906 Z200, not M906 Z200:200

I incorrectly assumed this applied to extruder motors too, where in reality it seems it does not. Not sure who maintains this text but maybe worth adding an extra note in there to make that a little clearer. Although with hindsight the previous included example of M906 X300 Y500 Z200 E350:350 should have been a clue.

Once I went through and added all the other standard motor parameters everything started working. As my extruders are not totally identical (metal BMG clone on HE & OG one on frame) I'm going to calibrate both extruders individually and go for a test print. Will report back after a few prints.

Thanks all for your input

@percar Good to know I'm not on a dead end! I suspect your right and will end up with this config but would like to try and make use of my spare drivers if I can. I don't know if a second small motor will really help that much (plus I don't have an identical one to hand!)

@deckingman Thanks, really helpful.

Sorry I forgot to put it, beta3.2 at the moment on Duet2 wifi +Duex5.

Seeing as I don't understand the T0 reference, probably not! Sorry could you give any more detail on what I should be including there?

Will have another quick go today and then post full config.g if I don't get it working.

@chrishamm
Could I set 50% extrusion ratios on both & half the steps per MM?

Yes, this isnt clear to me. In the Gcode library it has as example of ;

M906 X300 Y500 Z200 E350:350

but then says;

Example: If you have two motors on your Z axis, physically connected to Z and E0 stepper drivers, configured with M584 Z2:3, set M906 Z200, not M906 Z200:200

So maybe your right these E & Z are treated differently. If so that's great because I could run a much bigger stepper on the frame with a higher current. I could run an M906 E500:1200 to drive these for example.

Does this however mean I have to add the other extruder setup lines such as M350, M92, M566, M203, M201?

I guess it would be good to get confirmation that M567 P0 E1:1 will do what I think and set extrusion rates of 100 on both motors and that I'm not barking up the wrong tree!

On the weight issue I am trying to have my cake and eat it, or at least have the best compromise I can find. I'm currently running water cooled to run high enclosure temps so Zesty or similar would cost me that ability. Perhaps I just need another printer for faster prototyping!

I've got a significant reduction in ringing at higher speeds by downsizing so would rather stay with this setup if I can find a way.

In an attempt to reduce carriage weight I've reduced down to a pancake stepper on my BMG extruder. This works well most of the time but every now and again it will skip steps. Increasing current causes it to overheat and make it skip more.

Before I go back to a larger stepper I wanted to try running two steppers with BMG's in a push/pull type config. One mounted on the frame like a standard bowden setup leading to a direct drive type one on the hotend. However having problems with the setup.

If running both from the duet am I correct in that I can't configure different motor currents from each?
Would I be better just running with a physical splitter?

There are the lines I feel are needed but now neither motor is turning. Any ideas?

M569 P3 S0                                         ; physical drive 3 goes forwards
M569 P4 S0                                         ; physical drive 4 goes forwards
M584 X0 Y1 Z7:8:5:6 E3:4                           ; set drive mapping
M563 P0 D0:1 H1 F0                                 ; define tool 0
M567 P0 E1:1				           ; Set Extruder Drive Multipliers 1x each

Does anyone know what enclosure temperature @dc42 IR sensor should be happy up to?

What would be the weak link and how could it be improved? I'm not great with electronics but I'm guessing its the large electrolytic capacitor?