Duet2 wifi, nema17 - maximum speeds
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Hey,
Which is the maximum possible speed and acceleration I can achieve with my Nema 17 (and Duet2 wifi board)?
I received this warning when the speed was high: "Warning: Driver 0 warning: phase A may be disconnected, phase B may be disconnected."
Adi -
@adistr
That would depend on the specification of the motors. Did you use the RRF configuration tool to set up your machine?I haven't looked at all you other posts, but do you have a printer or a CNC?
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@nightowl999
Hello,
I used the RRF configuration tool, but the maximum speed and acceleration are too low for my needs.
And the printer I am using is not a standard model.Adi
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@adistr What speed and acceleration do you need?
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Maximum speed has several possible limits:
Motor performance:
Duet2Wifi is limited to 24V input which limits the absolute speed to about 400rpm on a typical 1.8degree 2A stepper like the LDO2504-48. (it'll be about 200rpm on a 12V system). Depending on the pulley size or gearing this will limit the absolute attainable speed. On a typical printer this means it's unlikely you will be able to pass max speeds of 500mm/sec assuming 80steps/mm on that axis and a 24C system. Note that on a Core* system combined axis moves may be limited further.Steprate limits:
Steprate limits govern how many step commands can be sent in a given time to drive a stepper. There is an old table on the reprap wiki that clocks the maximum attainable speed on a typical i3 style printer to roughly 300mm/sec at 16x microstepping. Since I don't know when this data was generated and how your custom machine is built, this may not be applicable for RRF 3.x or your custom machine. It seems plausible and within the physical drive limits of a 2-2.5A stepper motor as outlined above.Based on the absolute lack of details about your machine, your error message sounds like either a wiring error or an issue with sending too much current to your driver. It's possible it may happen when you try to outrun the stepper (motor performance case above) but I have no experience with that.
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@oliof said in Duet2 wifi, nema17 - maximum speeds:
...................There is an old table on the reprap wiki that clocks the maximum attainable speed on a typical i3 style printer to roughly 300mm/sec at 16x microstepping. Since I don't know when this data was generated and how your custom machine is built, this may not be applicable for RRF 3.x or your custom machine.
Just for info, there is a bit more up to date information on step pulse frequencies in DC's spreadsheet here https://docs.google.com/spreadsheets/d/1AWA1wLbOaYzxzdQa5LRZvn9rgEk2BuluHy6-_OnD6FY/edit?usp=sharing
Of course, that only takes into account the maximum step pulses that the various board/firmware combinations can achieve, and not the physical characteristics of the motor and/or machine that it's connected to. But it's a useful guide, especially if one starts playing around with high micro-stepping values.
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It sounds like the backemf may be exceeding the input voltage.
Spend some time with the EMF calculator to work out what your max speeds with the motor would reasonably be.
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@phaedrux @deckingman thanks for the additions!
