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Author Topic: Very slow gotos when Ustep Gear Changing is disabled  (Read 4898 times)

cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #15 on: May 10, 2017, 21:10:47 »

Hi Tom, I'm using a Vixen GP, so the ratio's are for the EQ5 custom pulley. I presume Zh is using a different mount and thats why he can get 800x with the gear changing disabled.

Thanks for looking into it, glad you can do the maths lol.
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #16 on: May 11, 2017, 12:12:44 »

Sorry Tom I seem to have noticed another problem. :-[. The Sidereal tracking doesn't seem to be as smooth as it was. It seems to move one step at a time instead of continuous motion, causing targets to move backwards and forwards slightly. This Jupiter at 1000mm focal length:

https://www.youtube.com/watch?v=zyUQ6-TTjUo&feature=youtu.be




« Last Edit: May 11, 2017, 18:10:10 by cuivenion »
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #17 on: May 11, 2017, 18:11:14 »

Just to add, the scope reticle in Stellarium also mimics this movement. Sorry Tom, probaby sick of me lol.
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #18 on: May 12, 2017, 12:31:30 »

This is a video of the movement in Stellarium. I've increased the mag so you can see it. The fact that the movement occurs in Stellarium and in the scope makes me think that its a software and not a mount problem. Wether it's AstroEQ, EQMOD, Stellarium or Stellariumscope is another issue.

https://www.youtube.com/watch?v=2E1QLZjaw_s&feature=youtu.be

I'd ignore the first 10 seconds as that fast movement is caused by a gitch in the recording I think, It's the rhythmic back and forth movement that I'm wondering about.
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #19 on: May 12, 2017, 12:41:04 »

Also, this movement occurs in Stellarium without the mount being connected, just running EQMODand Stellarium with the AstroEQ Box.
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TCWORLD

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #20 on: May 13, 2017, 12:55:50 »

Please save the config you are using with the save button, and attach the .conf file to a post here.

I really don't know what is going on as for me it seems to work perfectly well.
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Tom Carpenter (AstroEQ)

cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #21 on: May 13, 2017, 16:50:00 »

Hi, Here's the config file. From the latest config you recommended. Just too let you know though, that this occurs in the beta and pre beta. The movement also seems to occur in CDC although it is harder to make out as the reticle is very big. I've tried using a different USB and com port, but no luck.
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TCWORLD

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #22 on: May 13, 2017, 18:51:04 »

I hadn't grasped that it was happening in the previous version too.

You might want to read this thread. It seems to match what you are having problems with (there are a couple of different solutions to try at towards the end of the thread). I didn't think to mention it before as I thought the issue had only appeared in the new firmware.
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Tom Carpenter (AstroEQ)

cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #23 on: May 13, 2017, 19:55:17 »

Thanks Tom, I only noticed it was in all versions when I checked them all today so o worries there. Thanks for your help. I'll look at the thread and get back to you.
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #24 on: May 13, 2017, 20:05:33 »

Upon a quick perusal of the thread I'm not sure how it will help. I've tried running AstroEQ without the motors connected and the tracking fault shows in the software regardless. Unless I'm missing something that must mean the problem lies with astroeq, eqmod or stellarium/CDC.
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TCWORLD

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #25 on: May 13, 2017, 21:04:20 »

The zig-zag in stellarium/CdC is not necessarily real. While the AstroEQ is keeping track of the current encoder value internally, EQMOD is only polling this periodically (typically ~5 times a second). That means that as far as it any planetarium is concerned, the mount stops for 200ms, then moves a chunk, then stops for 200ms, then moves another chunk. This essentially means that it appears to oscillate in the RA axis. This is quite normal, and not representative of what the mount is actually doing.

The step rate from the AstroEQ is pretty constant  - there is some minor dithering for improved accuracy, but that is only +/-500ns added to certain pulses to account for rounding errors which should not be noticeable at all.

This is one of those weird cases where two things seem to corresponding to each other, but are actually most likely unrelated.

If the mount is not moving smoothly it's likely the issue raised in the other thread with the motors not handling the microstepping well, something which can be mitigated as shown in the other thread.
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Tom Carpenter (AstroEQ)

cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #26 on: May 14, 2017, 00:59:50 »

Thanks Tom, I understand things a bit better now. The other thread seems a little over my head but I'll read it again and try to sort something out.
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cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #27 on: May 14, 2017, 03:16:18 »

Hi, I've read through the thread and I'm a bit confused by a couple of things. It seems to be about the DIY version of AstroEQ that I don't have. I have the pre built 4.5 version. Also one of the posters recommends using these motors to fix the problem:

http://www.omc-stepperonline.com/nema-14-bipolar-stepper-75v-05a-23ncm326ozin-14hs170504s-p-94.html

These are the exact motors I already use on my mount.  They are high voltage low current and the thread seems to be about motors that are the opposite so I'm unsure how the proceed.
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TCWORLD

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #28 on: May 14, 2017, 10:40:45 »

Quick summary of that thread:

It has information about putting the DRV8825 driver boards into fast decay mode which at the expense of some noise results in better performance (see this post).

Alternatively it is possible that you need to adjust the current limit to try and give the motors a little bit more oomph.

Third point is to give the mount a service - make sure the axes are not too stiff.
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Tom Carpenter (AstroEQ)

cuivenion

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Re: Very slow gotos when Ustep Gear Changing is disabled
« Reply #29 on: May 14, 2017, 12:37:12 »

Ok thanks I'll give it a go.
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