Microstep interpolation.
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Okay, I'll try that later today. Hopefully you can confirm what I find.
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If it only works at 16x that would explain why I got more noise at 32x with interpolation "enabled" when I tried it. I didn't try 32x with interpolation off, but I definitely had more noise with it on. It was still quieter than the 0.85 with 16x micro stepping.
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sorry to revive an old thread, but i'm considering buying a Duet Ethernet and i'd like to know if its possible to set a Minimum step Increment? I'd like to stay within my steppers Full Step, but while still using 256 microstep… i was lookin into the tmc5130 chip, the datasheet seems to indicate that it could support it, but there is not a single implementation that support more than 1.4A right now(probably more like 1.2A)... And i'm not willing to wait...
So, Full steps, at 256 microsteps, can it be done in software? -
Errr, not my strong point but I always though micro stepping was simply chopping full steps in to segments. So say a 1.8 degree motor gives 200 full steps per revolution. Using 16x micro stepping would mean 200 x 16 = 3,200 micro steps per full revolution etc.
Edit. So at 256 micro stepping there would be 200 x 256 = 51,200 microsteps per revolution but still 200 full steps.
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Microstepping is meant for reducing noise not augment precision. On a Delta, your precision is already off by your inability to accurately measure tower position and angle. If the tower wiggle even just a bit, you'll never be able to print a square so there is no point in buying powerful high precision geared steppers. You need precision in a delta though, because the motor movement does not always translate to the same distance on the bed. Microstepping is then required to at least offset for that. But with a cartesian printer and a 400 step per revolution stepper, its not too hard to get to 0.05mm, i dont see any reason to use microstepping then, especially if it remove precision… i have no idea if a 256 microstepper is precise or not, but i kinda dont want to take my chances.. my delta days are over... i want to leave that nightmare behind me..
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Ref precision, quite so. A typical stepper motor has a step accuracy of 5% per step, non accumulative. Microstepping doesn't improve that but neither does it make it any worse. So yes, you should choose your pulley sizes/gear ratios or whatever so that the required resolution can be met by an integer of whole steps. On a Delta, it might well be worth using 0.9 degree steppers which give you 400 full steps per revolution - probably with the same non accumulative 5% error but this will in effect be half the error than a 1.8 degree motor.
So as we agree that micro stepping has no bearing on accuracy, I'm not sure that I understand your original question.
Reason for edit - typo
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ok, so if i understand this, every time the motor reach the full step position the precision is kinda reset so that you'll never have more than that ±5% of a Full step + whatever the microstepping error might be…
Gezz... took me a while to figure that out wow...
Looks like my delta printed as good as the way it was built... now i feel better...
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That's my understanding. So for any given position, the accuracy will be within 5% of one full step. So 0.09 degrees for a 1.8 degree 200 step motor, and 0.045 degrees for a 0.9 degree, 400 step motor.
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What is the optimal setting for microstepping? Should I change my settings to 256 or leave it at 16? Thanks!
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If you switch to true 1/256th you might be limited to relatively low speeds, asthis mode puts a really big demand on the processor. Try it and see how fast you can move, more of a challenge for deltas moving 3 motors simultaneously. If you want noise reduction then 1/16th with interpolation seems the logical choice. The modes in between might offer theoretical gains over 1/16th but not as much as smaller pulleys and 0.9 degree motors.
