Update Looks like this was a mapping issue where I was calling for drives numbered 7 and 8 when they had been mapped earlier to direct calls for extruder drives 0 and 1 to 7 and 8. Have not fully resolved, but was able to get movement!

Hi There, I am having a problem commissioning a from-scratch 3d concrete printer. I have two concrete extruder channels that do not require heat, and that are driven by external drivers connected to expansion header pins. (#7 - E4 axis, #8 E5 axis) I have not been able to get any motion out of the extruder axis. I have been able to successfully move by defining as x, y, or z axis so It is not an issue with the drivers or step signal timing. I believe there might be an issue with how I am defining a tool that does not require a heater. (While it may be useful to track concrete temps in the future, these outputs do not require heaters)

The board seems to be "blind" to this particular code snippet in config.g. It does not produce any tool to select:

M563 P0 D7 H1 ; Define tool 0 Color Mix - No H field means no heater
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

The following code produces a tool that is selectable, but no motion or errors results:

M563 P0 D7:8:3 ; create a tool using extruder drives 0, 2
G10 P0 ; Set initial tool 1 active

The reprap configuration tool does not seem to play nicely with creating extruders with no heater. Filling out the fields for no heater resulted in the web control interface calling for temperatures to be within some set of bounds before it would allow movement.

Here is my full config code:

; General preferences
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

; Network
M550 Psilverwoodspyder ; Set machine name
M552 S1 ; Enable network
M587 S"****" P"" ; Configure access point. You can delete this line once connected
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet

; Drives
M569 P0 S1 ; Drive 0 goes forwards
M569 P1 S1 ; Drive 1 goes forwards
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S1 ; Drive 3 goes forwards
M569 P4 S1 ; Drive 4 goes forwards
M584 X5 Y6 Z2 E7:8 ; Apply custom drive mapping
M350 X16 Y16 Z16 E16:16 I0 ; Configure microstepping with interpolation
M92 X70 Y70 Z540 E55:37 ; Set steps per mm
M566 X900 Y900 Z12 E120:120 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000 Y6000 Z2000 E3000:4560 ; Set maximum speeds (mm/min)
M201 X20 Y20 Z5 E20:20 ; Set accelerations (mm/s^2)
M906 X800 Y800 Z2000 E800:800 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S180 ; Set idle timeout

; Axis Limits
M208 X20 Y20 Z0 S1 ; Set axis minima
M208 X1500 Y880 Z315 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S0 ; Set active low endstops
M574 Z1 S1 ; Set active high endstops

; Z-Probe
M558 P1 H5 F120 T6000 ; Set Z probe type to unmodulated and the dive height + speeds
G31 P500 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
M557 X15:1485 Y15:865 S20 ; Define mesh grid

; Heaters
M140 H-1 ; Disable heated bed

; Fans
M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P2 S1 I0 F500 H-1 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned off

; Tools
M563 P0 D7 H1 ; Define tool 0 Color Mix - No H field means no heater
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 D8 H1 ; Define tool 1 Backer Mix
G10 P1 X0 Y0 Z0 ; Set tool 1 axis offsets
G10 P1 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C

M563 P0 D7:8:3 ; create a tool using extruder drives 0, 2 and 3 and heaters 1 and 3
G10 P0 ; Set initial tool 1 active and standby temperatures to 0C

; Automatic saving after power loss is not enabled

; Custom settings
M564 S0 H0 ; Enable movement without endstops being checked
M569 P7 R1 T5:5:5:0 ; Set step timing to external drivers
M569 P8 R1 T5:5:5:0 ;

; Miscellaneous
T0 ; Select first tool

Could someone provide an example code snippet defining (and activating?) an extruder tool connected to expansion header that does not require heater? Thanks!

I am working on large-scale, multi-axis application that requires duet board to be positioned close to end affector. I would like to mount the Paneldue on the stationary control cabinet. This will require extending the four wires that control and power the panel 5-7m. Has anyone done this successfully before or envision any problems with this? I am planning on using shielded 24ga control wire.

@dc42 One of the things I am worried about is setting mix ratio between channels driven on the board and channels off. I see in another thread that this can be an issue. I need to synchronize the concrete extruder axis (160watt - NEMA 34) with a smaller color dispensing stepper (~20 watts - NEMA 23) Do you anticipate an issue configuring tools with mix ratios with both onboard and external drivers?(Perhaps question for separate thread)

@jrdm I found what I think will work for power supply and am going to try to run this off the board, as you suggest. Thanks for input.

Thanks for quick reply! The motor is a Minebea 23KM-K709-[Illedgible]. Looks like they are rated for 3amps? This axis requires 26 watts of mechanical power and I think this motor is on the edge of that.

I do know that the driver is active-high.

As noted, even with the 0.1v low-state of the Arduino it still interprets a manual wire touch as a step (Motor jumps) and then does not see any subsequent steps generated by Arduino or Duet.

Hi There, new to Duet (and electronics in general) and very impressed so far. My project is a 3D concrete printer. I am driving 5 axis of motion with substantial inertia and hence external stepper drivers. I have 4 of the axis successfully powering large NEMA 34's and controlled via 60V 8A external drivers connected to expansion header. The final axis involves communicating with a proprietary stepper driver I am re-purposing from another piece of equipment and powering a smaller NEMA 23. The board is clearly labeled Step, Direction, Enable, but when connections are made to the Duet, no motion results.
I have made all connections (Dir, Stp, Enable, Gnd) and can get the motor to step by manually breaking connection in step wire, and even change direction by connecting/disconnecting direction wire. From this I assume that this proprietary board "likes it" when the low signal returns to zero voltage. It seems that the direction and step pins coming out of the Duet always read 0.5v even when signal is low.

I have reviewed the documentation and don't see how to adjust the minimum signal voltage.

I know the signal out from the Duet is "good" as the same wires connected to other external drivers result in motion. I have adjusted the pulse timing with no results.

I tested the external driver just now with and Arduino and GRBL. The Arduino step pins read 0.1 volts on the low signal. Driver did not respond to this either.

Maybe this is a hardware issue where I need to somehow shift the voltage of the signal down?

Thanks for your help!