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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

A question to Jean-Luc..

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Hi,

I would like to know if there is some more information about the PPEC from Jean-Luc's ppa ?? is the procedure the same as using PPEC with the HC or is there some other procedure ??
Using the HC you get a long beep when the PPEC-training is complete, so how do I know that using INDI ??

Br,
/Markku
7 years 2 months ago #14081

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Replied by Jean-Luc on topic A question to Jean-Luc..

Hi /Markku,
Some problems with my ISP connection made me leave this during the last 2 months.
I've now added the detection of PPEC training completion on my github fork and just resynced with upstream indi.
I'll make a pull request when it will be confirmed that everthing works.
So I added:
- for every mounts: ST4 rate selection (0,25..1x), it is forced to 0.5x at each connection as there is no way to know the current selection.
- for capable mounts (EQ8/AZ-EQ6/AZ-EQ5 publish their capabilities, they are displayed by the driver on connection): aux. encoders (disabled at startup/connection) and Permanent PEC (permanent because values are stored in the motor controller eeprom).
For equatorial mount, the DEC PPEC is not functionnal as the motor controller refuses to start PPEC training if not tracking (motor running).
There is no sound when training completes but a message and the PPEC training switch gets back to idle state.
Concerning the procedure, I don't have the HC, but I think this is the same.
Engage tracking, engage PPEC training, the motor controller will start PPEC recording when it detects the worm indexer, then every fixed amount of steps, a mean speed is recorded in the eeprom. A status bit indicates when the PPEC training completes, the indi driver simply uses it.
I have considered the possibility to download the PPEC table into the indi driver, it would be the list of periods used in a worm rotation (192 16 bits-period values if I remember).

Regards,
Jean-Luc.
The following user(s) said Thank You: Markku
7 years 2 months ago #14123

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Replied by Markku on topic A question to Jean-Luc..

Hi Jean-Luc,

That will be a really nice addition to Ekos :)
It looks like the weather will be good tomorrow night so I'll give it a try and see how it works.

Downloading the PPEC table could be useful for checking how good or bad the worm is and maybe also if there is a way to clear the PPEC table ??

Thank you for a great work!!
Br,
/Markku
7 years 2 months ago #14125

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Replied by Markku on topic A question to Jean-Luc..

Hi Jean-Luc,

I did some testing last night but how can I tell the difference between using RA PPEC or not using RA PPEC ??
It should be visible in the guide window but I could not see a big difference because the window timespan is a bit short.
Anyway, I post 2 images to show what it looks like.

Br,
/Markku
7 years 1 month ago #14422
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Replied by Jean-Luc on topic A question to Jean-Luc..

Hi Markku,
First, thanks for testing.
I would suggest to start by checking that PPEC is really effective: simply engage tracking and look at the RA period number. when PPEC is off it will stay constant at the normal tracking period, when PPEC is on, it should vary periodically as the periods will be a series of means of periods recorded during the training session. You may also keep a log of this training period, that could give an idea of the attended periods.
Now when you engage autoguiding (using ST4 or pulse guidng) , PPEC will be disengaged during guiding corrections, by the frimware (ST4) or by the driver (eqmod). If you could disengage autoguiding, you may perhaps see more clearly a difference between the drift graphs.

Jean-Luc.
7 years 1 month ago #14427

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Replied by Markku on topic A question to Jean-Luc..

Hi Jean-Luc,
Sitting right now and testing :) Well, I don't see the "Worm period" changing at all, it just shows RA Period 439 all the time but if I switch off the Directions control in RA I can tell there is improvement.
One thing I noticed is that the "Aux. encoders, RA Steps" do change ? maybe that is normal because things get a bit worse when enabling the Aux. encoders.
Is is ok to have the DEC guiding active and just disable the RA guiding and still have the RA PPEC doing its stuff ??
Br,
/Markku
7 years 1 month ago #14473

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Replied by Jean-Luc on topic A question to Jean-Luc..

Hi Markku,
"Au temps pour moi", you're right, the periods are not updated in the driver. Actually they are cached here as the driver is the only one supposed to change them. I may change that in a future update. The aux encoders values are displayed for information, I think it is better to leave them disabled.
Concerning guiding, you may effectively keep DEC autoguiding while using PPEC in RA, that should work.

Jean-Luc.
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7 years 1 month ago #14499

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Replied by Markku on topic A question to Jean-Luc..

Hi Jean-Luc,
As usual I thought I did something wrong :)
The RA PPEC works as it should so no problem there, but I'm a bit curious about why DEC PPEC is'nt working, according to HC manual there is only RA PPEC so why not for DEC ? my guess is that there is no need for that if the mount is correctly aligned but correct me if I'm wrong..
Thank you for your hard work!!
Br,
/Markku
7 years 1 month ago #14552

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Replied by Jean-Luc on topic A question to Jean-Luc..

Hi Markku,
Actually both axis controllers have the same firmware, so if there is PPEC in RA, there is also PPEC in DEC. As it is there, the driver exposes it.
Now as you have seen, PPEC may only be engaged if the axis motor is running (normally in tracking). As there is no tracking in DEC for equatorial mount,
the driver receives an error code from the firmware when you try to engage DEC PPEC. If you manually start the DEC motor at low speed, that should work.
PPEC is useful when you want to correct worm gear errors (which are periodic) in a constant speed move. Not sure if there exists cases where 2 axis constant tracking may be useful. That would draw an ellipse in the sky if i'm correct.
Jean-Luc.
The following user(s) said Thank You: Markku
7 years 1 month ago #14598

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Replied by Markku on topic A question to Jean-Luc..

Hi Jean-Luc,

Now I know the reason :)
Thank you for explaining that, I'll do some more testing when weather permits but so far everything is working just fine.

Br,
/Markku
7 years 1 month ago #14631

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