Re: TMC2130


Joe
 

Howard, 
In order to adjust the drive to the worm gear, on this mount you need to remove the steppers to access the set screws to adjust the tension. I’m trying to find some balance between smooth movement and tightness. Too loose and I have noticeable play when pushing the mount by hand, too tight and I am stressing the steppers. It’s a process to move even 1/4 turn on the set screws, it’s very time consuming. It seems I should be doing this process with the mount fully loaded as it changes with the weight dynamics. I believe I need a much lighter scope for this mount, but that’s another problem. Also while I don’t see much if any wear on my worm gears I’m aware that poor worm/gear engagement is a concern when thinking about precision, thinking ahead if PEC could help out...I did disassemble the mount, remove the old grease and used the recommended “superlube”.
If my goal is to achieve 28800 steps per degree, I’m using 16 & 40 teeth gears with a 144 worm I get: 128M/S 51200SPD, 64=25600, 32=12800. Is 128M/S ok for the LV8729 .9 steppers? The RA does move very smooth and quiet with these settings. Haven’t tried outside under the sky yet. 
The slew rate is another story. The first time I set this up was using Khalids calculator and his auto generated Config.h file.
I see that the MaxRate is now DesiredBaseSlewRate. If the STM32 is 20 you enter that number in the Config.h file and also add a lower number in Microsteps_Goto or just leave it blank? I’ve tried multiple combinations and am getting painfully slow skew rates or bad noises and skipping from the steppers. It’s likely I’m misinterpreting what values are actually needed.






On Friday, February 14, 2020, 2:16 PM, Howard Dutton <hjd1964@...> wrote:

On Thu, Feb 13, 2020 at 04:56 PM, Joe wrote:
I’ve got some concerns about the inefficiency of my mount.
I'd like to hear what the problem is before guessing at a solution.

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