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Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?

 

One thing to realize is that Gemini has a greater internal precision than just one step. It reads stock servo encoders in quadrature, meaning it's capable of detecting an offset of 1/4 of a step size. For G11, one step is 0.5625 arcsec, so the actual offset can be detected with precision of up to 0.1406 arcsecs.?

Regards,

? ? ?-Paul


On Sun, Jun 13, 2021 at 10:30 PM, Cyclone wrote:
The Gemini L4 manual states:
"In addition to support for Losmandy and Mountain Instruments mounts, Gemini L4 now?supports custom mounts. The user can setup the main parameters of his mount: the gear?ratios and direction of spur gear and worm gear and the servo motor encoder resolution.?The step resolution can reach from 0.1 arcsec per step (servo motor encoder tick) up to?2.5 arcsec/step."

The serial commands definition L5 v2.1 states:
"Gemini L4 supports step sizes from 0.2 arcsec/tick to 2.5 arcsec/tick."

Therefore it is unclear what the minimum step size is, but both definitions would support a 512 tick encoder assuming you do not modify the gearbox.

Also, I wrote a document a while ago that explains how to calculate the step sizes which you may find useful (see attached).

Eric
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