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Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Howard Dutton
 

BIGTREE is much more open/informative about their implementation also:

https://github.com/bigtreetech/BIGTREETECH-S42A-V1.0


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Howard Dutton
 

Looking closely the BIGTREE S42A is a different creature vs. the MKS units.

https://www.biqu.equipment/products/sdgjgh

It has usb.
It has more advanced AS5047D encoder chip (read this.)
It has the proper 100uF power supply cap.
Unknown about pull-ups on the signal lines but layout in that PCB region seems similar to the MKS 42B and not like the MKS 42A.

$38 from Aliexpress.


Re: Stupid Question about pier side

Charles <Charles_Lemaire@...>
 

Hi all,
 
In the FS2 system there was no side of pier but a pointing direction wich is defined in the opposite manner. That's why Thomas and many FS2 users are when they switch to onstep or teenastro confused.
 
Charles
Gesendet: Freitag, 03. Januar 2020 um 13:52 Uhr
Von: "Howard Dutton" <hjd1964@...>
An: main@onstep.groups.io
Betreff: Re: [onstep] Stupid Question about pier side
On Fri, Jan 3, 2020 at 04:50 AM, Howard Dutton wrote:
Pier side West means the telescope is West of the pier looking at the sky East of the meridian.
Well, it's really more complicated than that...
https://ascom-standards.org/Help/Platform/html/P_ASCOM_DeviceInterface_ITelescopeV3_SideOfPier.htm


Re: Stepper motor mount for Losmandy GM-8

Howard Dutton
 
Edited

On Sun, Dec 22, 2019 at 08:51 AM, Khalid Baheyeldin wrote:
An advantage of those 5-phase motors is that they could be connected with just 1:1 pulleys for EQ4 (144 teeth at 1/64 microstep).
That can be helpful in cramped situations where a bigger pulley is obstructed (like my mount).
I tested a 1000 step 5-phase stepper motor yesterday.  It was smooth and accurate in its motion but shaft angular displacement was still there and every bit as significant as any of the 400 step NEMA17 bipolar motors I tested.  The MKS SERVO42B on the other hand should in theory do fairly well on a GM8 (provided torque is sufficient,) but I would guess not as well as adding a 4:1 reduction to a standard 400 step motor/driver.

Test results for the 5-phase and MKS SERVO42B are near the bottom of the page:
https://onstep.groups.io/g/main/wiki/Stepper-Motor-Accuracy


Re: Stupid Question about pier side

Howard Dutton
 

On Fri, Jan 3, 2020 at 04:50 AM, Howard Dutton wrote:
Pier side West means the telescope is West of the pier looking at the sky East of the meridian.
Well, it's really more complicated than that...
https://ascom-standards.org/Help/Platform/html/P_ASCOM_DeviceInterface_ITelescopeV3_SideOfPier.htm


Re: Stupid Question about pier side

Howard Dutton
 

Pier side West means the telescope is West of the pier looking at the sky East of the meridian.


Re: Stepper motor mount for Losmandy GM-8

Howard Dutton
 

That should be a great solution John.


Stupid Question about pier side

Thomas Westerhoff
 

Well, that might be a stupid question, but since english is not my mother tongue, I better ask.
I can enter the pier side in Onstep. But what does that mean? Does "West" mean that the telescope is on the west side of the pier or pier west of the telescope?
--
Thomas Westerhoff
Kirchheim Observatory /Germany
http://sternwarte-kirchheim.de/


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Howard Dutton
 

If you do happen to get this working be sure to read about how the encoders work here:

https://onstep.groups.io/g/main/wiki/8-Advanced-Topics


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Howard Dutton
 
Edited

  • Last change to the GitHub master branch WiFi Addon was 22 days ago.  I wonder if the cheapo ESP8266 flash memory misses writing a bit here and there sometimes.
  • I use the same Arduino IDE version.
  • Normally the OnStep.ino file is in the left most tab in the IDE, I don't see it there in your screen shot.
  • I see the directory name enclosing OnStep is called "Onstep" not "OnStep"... windows file system isn't case sensitive but perhaps that's tripping up the IDE.


Re: Stepper motor mount for Losmandy GM-8

John Scherer
 

I decided to upload the design to Thingiverse.  Its just easier that way ;-)


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Thomas Westerhoff
 

The good news:
The latest Wifi Addon (github checkout this morning) works with the Onstep 3.13c on my Teensy3.6.

The bad news:
I'm going out of my mind. As I said I checked out the latest code version of Github (master) this morning and now I can't compile OnStep (Teensy3.6 MaxPCB2) at all. The Arduino IDE (1.8.10) claims the Align.h file is not there, but it is there in the editor as well as in the directory, as you can see. I'm beginning to hate the Arduino IDE.


--
Thomas Westerhoff
Kirchheim Observatory /Germany
http://sternwarte-kirchheim.de/


Re: Buying an EQ5

julianporter5@...
 

@Khalid For sure I will report back here how I get on, I’m some way off but at least I think I’m going in the right direction.


Re: Buying an EQ5

Peter Dulowsky <peter.dulowsky@...>
 

This is just my experience with polar alignment and OnStep:
I have EQ5 mount with a short tube refractor that I use for visual only. I polar aligned the mount once and marked the position of the tripod legs on the pavement. For each session I just position the tripod legs on those marks and do the 3 star alignment. The error is usually around .5 deg that Onstep can handle rather well. I found no need to re-do polar alignment of the mount for every session.
When I observe away from my home location I don't use the polar scope either. I just level the mount, move the OTA to home position and turn the whole thing as necessary to get the polaris as close as practical to the dot in RDF. Then I do 3 star alignment and all is fine. Since all of my away from home locations are within 30km I do not need to play with altitude adjustment at all.


Re: Stepper motor mount for Losmandy GM-8

John Scherer
 

I'm mostly done with this 4:1 belt drive for the Losmandy GM8 and you can look at the design here.  I'm just waiting on pulleys and belt coming from china and I can test this, though I have no reason to believe it won't work. If anyone wants STL's for printing let me know. 


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

--Oz--
 


Re: Buying an EQ5

Khalid Baheyeldin
 

On Thu, Jan 2, 2020 at 10:44 PM, <julianporter5@...> wrote:
Do you think aligning to the North Star with a laser will be good enough to then use the refinement function?
To get this perfectly right, you need the laser to be attached to the mount itself (not the optical tube), and you need to have it aligned (e.g. center Polaris through the polar scope opening, and then point the laser to Polaris). That way, the laser and the RA axis are aligned.

I would say that skip the laser, and just center Polaris through the polar scope opening, then do the 3-star + Refine PA routine. After all, Polaris is 40 arc minutes away from the NCP, and Refine PA should be able to handle that error range (and a bit more too).

Also try the smart phone sensors method, which I described before, and is linked to here, indoors first, then under the stars. Let us know how it works.


Re: Buying an EQ5

julianporter5@...
 

That is music to my ears. Using a polar scope is no fun at all especially when everything is at the wrong height and you are breaking your neck trying to look up and making fine adjustments.
Do you think aligning to the North Star with a laser will be good enough to then use the refinement function?


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Howard Dutton
 

For now... on my MaxPCB2:  Using the latest OnStep and Wifi Add-on.

At the moment my LXD75 mount I keep around to test this is in pieces with no encoders hooked up but otherwise everything seems to fire right up as expected.  I used ESP8266 v2.4.2 in the Arduino board manager and an unpatched Encoder lib, otherwise your exact settings where known.



Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

fetoma
 

I fixed it Khalid.

 

Thanks,

Frank

 

From: main@onstep.groups.io <main@onstep.groups.io> On Behalf Of Khalid Baheyeldin
Sent: Thursday, January 2, 2020 6:09 PM
To: main@onstep.groups.io
Subject: Re: [onstep] Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

 

Note that the first two links are to the Servo42A, and not the Servo42B version.
Listings on the eBay show that the B version has higher resolution (40.5 arc seconds).

Here is the repo for the B version.