Duet3D

lee7670

It would be really interesting to support Image serving in the M291 command to better allow setup procedure to be shown that aren't easily described using text.

Use cases would be things like CNC setups, cleaning procedures, bed prep procedures, warnings to clear certain areas, etc.

I( have a couple of procedures where it would be really helpful to allow operators to check visual references against an image.

This could even be a pi exclusive feature if the Duet 3 MB6HC can't handle serving image files.

See this reference from HAAS on what this could look like. Massive Cheese warning....
https://www.youtube.com/watch?time_continue=2&v=_FxHfVKSOcs&feature=emb_logo

lee7670

The TMC4671 (https://www.trinamic.com/products/integrated-circuits/details/tmc4671/) can support steppers, Three-Phase, and DC motors/voice coils all running closed loop with Field Oriented Control for steppers and three phase motors.

Having an expansion board running one or more of these of these drivers with a power stage of 4 half bridges would allow maximum flexibility for motors/feedback.

There are dual feedback inputs so you can have one feedback mechanism for commutation and one for the actual position loop. They support both incremental ABN encoders, Hall sensors, and BISS-C/SSI encoders.

This would allow you to drive essentially any motor in step/direction mode from a duet.

Sweet tiny extruder with a micro geared dc motor for the smallest direct drive possible (https://www.pololu.com/product/3055)? You got It!

Drive a linear motor for the absolute fastest speeds for benchy printing? You can do it!

Motor torque feedback for extruder pushing force tracking and grinding prevention? Totally doable.

Want to drive a voice coil optical stage that you got on ebay just because? Easy.

Got your hands on some optical scales from a CNC and never want to use limit switches again? Sure.

That's a lot of functionality for a 12USD chip...

lee7670

It would be really nice if Duet Web Control could Log the temperatures and positions with timestamps that it receives from the board to a CSV locally on the machine where Duet Web Control is running in the Browser.

lee7670

You'll want to use the general IO headers for this.
Choose one, I usually start with IO_1.
Connect 5V_ext to V+.
Connect Ground to Ground.
Connect the Signal pin to IO_X.in

lee7670

I have a similar situation where this would be very useful in general for heater outputs for multi-heater beds and extruders and other things.

lee7670

Just set steps per unit to1?

lee7670

@dc42 is there more detail on how segmentation works? If I pause mid move with segmentation on, move a motor, G92 a couple axes and then resume, will it resume mid segment?

lee7670

It would be really nice if Duet Web Control could Log the temperatures and positions with timestamps that it receives from the board to a CSV locally on the machine where Duet Web Control is running in the Browser.

lee7670

Hi, I'm trying to tune a pesky unstable heater. Autotuning is unstable for various reasons, so I am having to tune M307/M301 Parameters by hand.

Do I need to turn off the heater to change the heater model/PID parameters or can I change them on the fly? It's hard to tell whether the new parameters have taken effect.

If I run a M301 to try some Legacy PID parameters and I want to switch back to an M307 heater model afterwards do I need to reset the board before doing that to remove the overrides or can I just send an M307?

lee7670

@dc42 Thank you, this is very useful!

lee7670

@dc42 now that 3.2 has been out for some time, would it be possible to get a better description of what the new M307 parameters do? the documentation is very vague and (https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control#Section_Manual_adjustments_to_the_heater_model_parameters) still refers to the deprecated parameter A (gain). Specifically, heater rate has no units on it. Would it be possible to see a quick diagram of what the heater loop looks like and where all the parameters feed in? I'll need to have one of our controls engineers fix a particularly troublesome heater and it would be good if they had a diagram of what's going on so we can tune on the fly.

lee7670

@o_lampe You can totally, do that, your stepping just changes the position target. You just have to tune it to react quickly enough, which is the trick... Gotta have a fast ADC and power stage as well as high resolution PWM. Edit: Gotta have a real fast control loop, an ASIC which does it for you (TMC4671 runs control loops at 200KHz according to a webinar I found from the trinamic people), or an FPGA to do similar.

lee7670

@o_lampe I've done some custom robotics work with the same motors and I was able to get a stable PID loop going no problem in a position mode. Even so, there are also brushed DC motors from reputable manufacturers like Faulhaber which would work great for the purpose.

lee7670