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Author Topic: Few questions regarding Config. utillity  (Read 2292 times)

igorb

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Few questions regarding Config. utillity
« on: February 24, 2016, 09:19:35 »

First of all, big thank you Tom for this project! I've put together AstroEQ board for my EQ3 mount and it works fine :). For the moment I'm using stock motors until I somehow make brackets for better steppers (Nema17, 1.8deg/step). While configuring AstroEQ I came into some doubts. When setting no. of microsteps and pressing update is that value taken only for that motor or both? Or to make it simple, is it possible to set different ustep settings for both motors? Another question is about slow and fast movement which cannot be changed. For example, when selecting 8 ustep mode utillity sets 8 usteps for slow and 1 ustep (or was it maybe 2?) for fast movement (thats for slewing I gues?). But when I select 4 ustep mode it takes 4 usteps for slow and fast movement! Why doesn't it take less usteps for fast movement? And one more for the end  ;D How to determine max slew rate? Is there some rule or is it trial and error?
Sorry if I missed something obvious. I did search through the forum but couldn't find answers.
Thanks!
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TCWORLD

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Re: Few questions regarding Config. utillity
« Reply #1 on: February 24, 2016, 14:19:05 »

Hi,

The step mode applies to both motors - you cannot have a different mode for each motor. When you change the mode you need to click the update button for both motors to recompute the values.

By design for high speed movements (go-to's and >200x manual slews), the step mode is changed to achieve higher torque. When I was originally designing AstroEQ, I was changing the prescaler for the timers in the firmware when switching step modes. This could only be done by a factor of 8, hence only step modes 8, 16, and 32 could use two different step modes. In the more recent firmware this is no longer the case, I just haven't introduced a way for the 1, 2 and 4 modes to change to a higher mode, and to be honest they don't need to - switching from 1/4 stepping to full stepping wouldn't really gain anything worthwhile in terms of torque.

The go-to rate is trial and error. For the stock motors, start with something like 40x. When EQMOD is loaded by the config utility, try different slew speeds using the NEWS buttons and see what the motors can achieve. Once you have found something they will work at, you can go back to the start and modify the go-to speed to match.

Kind Regards,
Tom.
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Tom Carpenter (AstroEQ)

igorb

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Re: Few questions regarding Config. utillity
« Reply #2 on: February 24, 2016, 23:24:52 »

Thank You for explanation. Everything's clear now  ;)
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