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Author Topic: Need a starting push on this  (Read 1360 times)

pedro.m.reis

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Need a starting push on this
« on: October 29, 2020, 00:41:27 »

Hi All
First thanks to Tom for this project!

I will be a proud owner of a plain, brand new SW EQ3-2 Deluxe (!) mount in a couple of weeks. Without any motors, etc.
So I came across this project and decided to try it, using only spare parts I have around.

So, I have:
- mega 2650 + ramps 1.4 with 8825 drivers, probably from Aliexpress or similar
- Wantai (?) step motors, model 42BYGHW811, specs in here: http://www.wantmotor.com/product/42BYGHW_EN.html

I'm not trained in electronic so bare with me... I'm a poor sysadmin :)

My first question is how to setup the configure values on program, and if any hw modification is needed on the arduino/sheild.

I'm still trying to read all tutorials/faqs/etc... But it takes time to catchup :)

Thanks
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pedro.m.reis

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Re: Need a starting push on this
« Reply #1 on: October 29, 2020, 21:51:57 »

Connecting the motors, a little help...

The board as the following labels on the motors pins:


    2B 2A 1A 1B

From the motor specs, its says that:
CoilA = BLK and GRN
CoilB = RED and BLU

Is the correct connection:
(option a)
BLK -> 2A
GRN -> 1A
Red -> 2B
BLU -> 1B

Or
(option b)
BLK -> 2A
GRN -> 2B
Red -> 1B
BLU -> 1A


Plz see photos

Im asking this because currently I have option B. So even that in slew mode both motors spin, when in track mode the tracker motor just shakes back and forward.. Any clues?
« Last Edit: October 29, 2020, 21:59:04 by pedro.m.reis »
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pedro.m.reis

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Re: Need a starting push on this
« Reply #2 on: October 29, 2020, 22:23:03 »

So I found the wiring diagram from the step driver and I think my connections are correct...
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pedro.m.reis

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Re: Need a starting push on this
« Reply #3 on: October 31, 2020, 03:00:40 »

So... back to my daily catharsis.
The 8825 drivers are fc&%$&/ up I guess. Changed to another driver I had lain around, some A988 compatible-ish ones...
Now it runs much smooter.. :)
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jslight

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Re: Need a starting push on this
« Reply #4 on: December 23, 2020, 13:26:31 »

The motors you linked are rated at 3.1V.  I'm assuming you're powering the AstroEQ with somewhere around 12V.  The 8825 drivers don't like large differences in input/output voltage.

Here's a blog post about the issue: http://cabristor.blogspot.com/2015/02/drv8825-missing-steps.html
« Last Edit: December 23, 2020, 13:37:25 by jslight »
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