Duet 0.6, external stepper drivers and voltage.

[aniron]

Hi,

I am considering upgrading my electronics with some additional stepper drivers, preferably I would like to run silentstepsticks at 24V (for the noise reduction) while keeping the rest of the electronics at 12V

1. Am I correct in assuming the Duet 0.6 can never have more than eight stepper drivers, four on the board, two on the shield or four on the duex4, or up to four external (e.g. silentstepstick) drivers?

2. I currently have the duet shield installed. Am I correct in assuming I can just connect two TMC2209 silentstepsticks to the unused step/dir pins of the expansion header.

3. Am I correct in assuming I cannot add more than two without removing the shield entirely?
   I would like to use the silentstepsticks for an X motor, an Y motor and an extruder motor for silent operation when only the main extruder is active. If that's not possible I will settle for the X and Y.

4. Would using a step-up converter like this one to power only the silentstepsticks with 24V for the lower noise level be a fundamentally bad idea? If yes, would even using a separate 24V PSU be inadvisable?
   

[dc42]

@aniron said in Duet 0.6, external stepper drivers and voltage.:

Hi,

I am considering upgrading my electronics with some additional stepper drivers, preferably I would like to run silentstepsticks at 24V (for the noise reduction) while keeping the rest of the electronics at 12V

1. Am I correct in assuming the Duet 0.6 can never have more than eight stepper drivers, four on the board, two on the shield or four on the duex4, or up to four external (e.g. silentstepstick) drivers?

Yes, unless you can get at the unused MCU pins that the Duet 085 uses for the 9th stepper driver.

2. I currently have the duet shield installed. Am I correct in assuming I can just connect two TMC2209 silentstepsticks to the unused step/dir pins of the expansion header.

That should work.

3. Am I correct in assuming I cannot add more than two without removing the shield entirely?

You could connect two more in parallel with the step/dir/enable signals that feed the two drivers on the shield.

I would like to use the silentstepsticks for an X motor, an Y motor and an extruder motor for silent operation when only the main extruder is active. If that's not possible I will settle for the X and Y.

4. Would using a step-up converter like this one to power only the silentstepsticks with 24V for the lower noise level be a fundamentally bad idea? If yes, would even using a separate 24V PSU be inadvisable?
   

That depends on whether your 12V supply can provide enough current.

[aniron]

@dc42 thank you.

I could then just leave one of the duet shield stepper drivers without a motor attached with no ill effects from driving a stepper via the stepstick attached in parallel?

I shall have to do some calculations on the power consumption.

Edit: It appears meanwell 15W 24V PSU's are of similar cost to the step-up converters. Could that be wired in parallel with a higher-wattage 12V PSU on the mains side, to not have to use a second power switch and mains cable?