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Author Topic: harmonic drive directly driven stepper EQ mount with EQMOD compatibility...  (Read 6339 times)

pterodyne

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Tom, as a side note :)

feature request if it would work.  A driver choice of "custom" that allowed you to pick from 1/1 to 1/512 uStep modes. then the rest of the maths are handled by the correct entry of motor step angle, worm gear etc..

Just a thought.
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pterodyne

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Tom, Im wondering if you saw the last two posts? 
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TCWORLD

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The problem with a custom setting is the AstroEQ firmware has to map the mode to pins. In hindsight I should have done the mapping in the config utility rather than the firmware.

Would you be wanting the mode selection pins to do anything? Or just the ability to set a microstepping mode for calculation purposes only?
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Tom Carpenter (AstroEQ)

pterodyne

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Well these drivers have dip switches so other than de soldering those I'm going to have to live with no control of the modes.  Short of modifying the config utility which I'm sure is considerable project for you, using these specs:

1.8 degree steppers
200:1 harmonic drive
4:1 pulley motor reduction
driver with dip switches to set up to 1/256 ustepping. (I need at least 32. 64 or higher would be better.)

I'm not completely sure what numbers I need to put into the config utility to trick my system into working.

I'm pretty sure gear changing should be disabled.  Not sure about multiplying the Motor gear ratio part.  I think I understood your original post years ago when I was in the early stages of this project, but at that spec had no motor gear..

As to the config utility at some point yes it would be awesome to choose a custom driver and ustep mode, and also be able to configure the pins.  Certainly I have little concept of the time involved. 

Thanks as always!

Bryan
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pterodyne

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I never had a workable solution even trying to trick the config.  In the end, I couldn't use the higher uStep modes like 64 - 256 because the slew speed ended up being too slow without gear changing.  Short of desoldering the switches and some how configuring the modes that way, Im not sure this is a workable solution.

Tom, can you confirm, the reason for the slow speeds with gear ustep changing disabled is because of the mega CPU?  cant deal with the number of pulses per rev?  I ask because I have a little more flexability with these drivers in the Onstep project using the same mega.  E.g. 1.1Dps slew rate with the mega and the drivers hard coded to 128uStep.
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