RPM mode?
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I'd like to set up a Duet3 board to run a step motor in a constant RPM indefinitely (or until I request a different RPM), where I set an RPM not a distance.
If this is already available I'd appreciate a point in the right direction, I couldn't find it in the docs or the forum.
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@JRDM its not currently available
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@JRDM I guess, you also want to use other steppers at the same time?
Maybe it's possible with RRF3.5 dual gcode stream?
I haven't seen any examples of dual stream yet. If anyone has done similar stuff, chime in please.You write a macro that converts RPM_to_gcode (calculate "F", based on steps/degree and the requested RPM)
Start the move with a long travel as second gcode stream. RRF doesn't allow infinite moves, but +/- 2^31 steps per single move is quite a lot.
Set M208 for this axis accordingly.Then you can start the first stream with the regular print file or whatever else you want to do
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@o_lampe That's interesting. Can the second stream be interrupted?
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@JRDM it's not currently available but it's been requested before and is likely to be included in RRF 3.6. In the nearer term we will soon have an RPM limit implemented when using torque mode on an closed loop expansion board (1HCL) or our forthcoming closed loop motor, and that could be used to provide this functionality.
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@JRDM I guess you can use conditionals in the macro or start/stop the second stream from within the first stream. But I haven't tried it.
There is this article Duet3 Wiki that might help you.
