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INDI Library v1.7.9 Released (23 Jun 2019)

INDI Library v1.7.9 is mostly a maintenance release to fix a few bugs in several drivers.

Focus Module revisited

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Focus Module revisited was created by MikeCEM60

Currently EKOS arrives at best focus by moving the sensor "in" and "out" with decreasing amplitude, thus arriving at minimum HFR value.

My home built focuser is belt driven, thus backlash in the system becomes an issue: this could be avoided:

First HFR is mapped in one direction (e.g.: "in" movements only) from outside to inside of best focus position. Once the V curve is established the focuser would rewind to its start position, and incrementally, using only "in" commands arrive at HFR minimum. Backlash avoided, that should eliminate most failed autofocus procedures.

Thanks
Michael
The following user(s) said Thank You: sterne-jaeger
1 week 5 days ago #40789

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Replied by wvreeven on topic Focus Module revisited

Michael, I don’t understand. Belt driven systems are known for their low backlash or even complete absence of it. My home built focuser is belt driven and has 0 backlash. Wouldn’t it be possible to eliminate the backlash completely?


Wouter
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1 week 4 days ago #40814

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Replied by sterne-jaeger on topic Focus Module revisited

I have the same problem as Michael with my Optec PDMS focuser. It is belt driven, but has nevertheless a backslash of 50-80 ticks.
1 week 4 days ago #40819

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Replied by DerPit on topic Focus Module revisited

My Pegasus DMFC fortunately has an internal driver setting to specify backlash.
But I do agree that it would be valuable to have a focus mode in EKOS that can take care of backlash by itself, for those that cannot set it in the driver.
A simple solution would be to have the focusser approach dialed-in values always from the same side, with a definable overshoot. I.e., to go from 10000 to 9950, it first goes down to 9800, and then up again to 9950.
Should of course be optional, so people with driver-internal backlash compensation can switch it off.
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI1600+EFW+ASI290 mini
1 week 4 days ago #40828

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Replied by knro on topic Focus Module revisited

Patches are welcome! An option can be added to mimic this behavior. Anyone needs help in setting up their development environment?
Jasem Mutlaq
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1 week 4 days ago #40837

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Replied by DerPit on topic Focus Module revisited

knro wrote: Patches are welcome! An option can be added to mimic this behavior. Anyone needs help in setting up their development environment?


That part is not the real problem. It's more understanding C++ and the layout of the code. KStars/EKOS is a complex beast and not the best starting point to learn I'm afraid :(

(Just wanted to have a look at what is needed to add also the Hour Angle to the "Mount & Alignment" overview, instead of issuing a wish. But even that looked to me like Olympus Mons to an ant :ohmy: )
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI1600+EFW+ASI290 mini
1 week 3 days ago #40880

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