And, worse, if the mount has any non-integer fundamentals, the recorded PEC curve will not match every worm cycle because each worm cycle will vary

Thankyou Ray. ?Explains quite the opposite effect to many are striving ?for?

cheers
--
Brendan

Ron and Jo-

Thanks for the replies.

Jon, you're right, I should have searched first. So I just did, and there are far too many topics to really parse out an answer easily, as is often the case in forums like this.

What I am hearing from both of you is that there is not an official or even semi-official recommended service interval. I am of Ron's camp, which is to address any issues if they come up and keep the worm lubed, which is what I have been doing.

I am pretty confident in the process to reset the worm adjustments as I have done this numerous times while experimenting with the Belleville washer set up. Not too worried about "how" so much as if there is a best practice "how often".

Thanks for the answers, and to anyone else who has any more experience, please keep commenting!

开云体育

Ray: will PEMpro generates a useable PEC curve for gearboxes above 25:1.....or ....will the PEMpro PEC curve
also fail if the problem is with the G-2 tick size data storage in the present firmware?

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Friday, June 18, 2021 8:18 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any reason not
to do this?

Nice catch, Ray. That could explain the puzzle... and also my puzzle on my 1:2 belt drive G11T.

(Please see my PEMpro question at the bottom of this email...)

Some thoughts...

The number of data points recorded in the PEC run is very small. For my 1:2 belt drive recorded at 1 sec intervals,
the number of points is only 2*319 = 638 points. Even recording at 0.1 sec intervals this is 6,380 points. (There is
a CPU RAM storage limit of 96 kbytes but there is also large external Flash available.)

Ray suggests that the optical encoder tick counts per worm rotation has to do with the puzzle.

A worm rotation value in raw optical encoder ticks is:
256 ticks per motor rev
x 25 stock gearbox (or 50 for me, 125 for PCBoreland) gearbox rotation reduction.

At 25 you get 6400
At 50 you get 12800
At 125 you get 32000 (over 25,600 Ray mentions as a limit)

The stock 25:1 and 50:1 gearbox values are at or below 25,600 Ray mentions as a limit for encoder nominal ticks.
The 125:1 gearbox goes higher.

However if the system is counting "quadruture" ticks (and we know it can) then the values become
At 25 you get 6400 -> 25,600
At 50 you get 12800 -> 51,200 (>>25,600 or 32,767)
At 125 you get 32000->128,000 (>>25,600 or 32,767)

I mention +/- 32,767 as the size of a C "int" 2 byte number. You can double the "int" value using "uint" to go from 0
to 65535 still taking only 2 bytes.

The question is: why is the tick count limit 25,600 or 32,000?
Isn't there sufficient RAM or Flash memory? Spec sheet says there is 98kb of RAM on the LPC2388 ARM CPU
chip. Maybe using only on-CPU RAM is the limiting problem. There should be huge room on the Flash drive for
the data.

An int size 2 bytes can go to +/- 32767
A uint size 2 bytes can go 0 to 65535
A long size 4 bytes can go to +/- (huge)

This now seems like a firmware code or memory storage issue. It would need the memory to allocate for a larger
tick number, or more PEC data collection numbers, or both. If anyone can address it, it will be Rene.

Ray: will PEMpro generates a useable PEC curve for gearboxes above 25:1.....or ....will the PEMpro PEC curve
also fail if the problem is with the G-2 tick size data storage in the present firmware?

All the best,
Michael






On Fri, Jun 18, 2021, 7:24 AM Ray Gralak <iogroups@...> wrote:


> PEC training quits after 48s, 1/5th period of the worm. I think this has to do Pec working with 6400 ticks
instead of
> 32000.

32000 is above the maximum number of ticks, which I think is 25600.

The tick count probably wraps at 25,600 so 32000-25600 = 6400, which would explain the 1/5 cycle.

-Ray

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of pcboreland via
groups.io
> Sent: Friday, June 18, 2021 6:22 AM
> To: [email protected]
> Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any
reason not
> to do this?
>
> Ray,
>
> PEC training quits after 48s, 1/5th period of the worm. I think this has to do Pec working with 6400 ticks
instead of
> 32000.
>
> Peter
>

PEC training quits after 48s, 1/5th period of the worm. I think this has to do Pec working with 6400 ticks instead of
32000.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of pcboreland via groups.io
Sent: Friday, June 18, 2021 6:22 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any reason not
to do this?

Ray,

PEC training quits after 48s, 1/5th period of the worm. I think this has to do Pec working with 6400 ticks instead of
32000.

Peter

I am speaking about trying to use the built in PEC recorder feature advertised as being internal to Gemini-2. It
does not work for the G11T. It appears it does not work for the 125:1 gearbox either. In both cases the G-2 quits
taking data before a complete worm cycle period is complete. Without using a complete worm cycle it cannot
generate a correct PEC correction curve.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Thursday, June 17, 2021 10:55 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any reason not
to do this?

Ray,

I am speaking about trying to use the built in PEC recorder feature advertised as being internal to Gemini-2. It
does not work for the G11T. It appears it does not work for the 125:1 gearbox either. In both cases the G-2 quits
taking data before a complete worm cycle period is complete. Without using a complete worm cycle it cannot
generate a correct PEC correction curve.

You are right....I have not used PEMpro. I have used Gemini-1 to generate it's internal PEC with good results. I
have used PECprep for PE analysis, not generate PEC for the Gemini system. I only use non-guided star
tracking to acquire PE data for analysis.

Best regards,
Michael






On Thu, Jun 17, 2021, 10:37 PM Ray Gralak <iogroups@...> wrote:


> I encountered the same problem as you report: the Gemini-2 PEC training acquisition time is broken. The
internal
> PEC that is advertisef to work in G-2 does not work. The only way to get a working PEC at this time is by
> purchasing PEMpro, then use a PHD2 unguided log file fed into PEMpro to have it create the correct PEC
file.

Michael, you obviously haven't used PEMPro, because you don't feed a PHD2 unguided log file into
PEMPro to create a PEC curve. Maybe you are thinking of the PEMPro Log Viewer, which does accept PHD2 logs
for analysis?

> I reported the G-2 problem to Renew Goerlich who asked me to download certain files from the G-2, but I
did not
> have a CAT5 cable connection so I did not deliver the files requested. Bottom line: G-2 PEC does not yet
work.

You must mean recording PE via an autoguider doesn't work, right? PEMPro does work with the Gemini-2
PEC.

BTW, recording via autoguider is likely to provide inferior results. In fact, this method doesn't work very well
at all if there are any non-integer fundamental frequencies, which is not uncommon. I can explain why this is so, if
this isn't obvious?

-Ray

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
> Sent: Thursday, June 17, 2021 8:56 PM
> To: [email protected]
> Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any
reason not
> to do this?
>
> PCBoreland,
>
> (What is your first name?)
>
> I encountered the same problem as you report: the Gemini-2 PEC training acquisition time is broken. The
internal
> PEC that is advertisef to work in G-2 does not work. The only way to get a working PEC at this time is by
> purchasing PEMpro, then use a PHD2 unguided log file fed into PEMpro to have it create the correct PEC
file.
>
> The PEC training in Gemini-1 does work. You don't need PEMpro if you have a G-1. You can use
PEMpro if you
> want of course.
>
> I reported the G-2 problem to Renew Goerlich who asked me to download certain files from the G-2, but I
did not
> have a CAT5 cable connection so I did not deliver the files requested. Bottom line: G-2 PEC does not yet
work.
>
> Meanwhile I am happy to read your detailed reports on the 125:1 gearbox. I agree that PHD2 autoguiding
will
> correct the DEC and RA. It would be the same if tracking the sun or moon or a planet...you must use
autoguiding.
>
> And yes. The 125:1 vs 25:1 means that slewing will be somewhere like 5x slower. Yet it is the tracking
perfection
> that you are focussing on.
>
> Best,
> Michael
>
>
>
>
>
> On Thu, Jun 17, 2021, 8:10 PM pcboreland via groups.io <pcboreland@...> wrote:
>
>
> As was pointed out by David Partridge, it is possible to change out the gear box on just RA if one uses
the
> web interface to select the parameters. I installed the 125:1 gearbox earlier in the day, and have been
able to
> gather some initial data. As might be expected there is good and bad.
>
> The Good. Unmoded, my Ra guided on average 30% worse than the Dec axis looking back over 6
months
> of logs. With the limited short run tests done earlier this evening RA is now guiding 10 to 20% better than
Dec. A
> huge shift in performance. A seeming improvement of greater than 0.6 arcsec on 10 min runs. I'll be
imaging in 90
> minute blocks later tonight so will hopefully get data worth sharing, and this improvement holds
>
> The Bad. 1. Ra runs slow. Over a 3hr period it fell behind the object a noticable bit. This I assume is
> because the Ra tracking divisor is set to 89754 when it needs to be set 89754.2. I go not think this is a big
deal as
> guiding ought to handle this problem. 2. Pec training runs for just 48s. 1/5th of a worm cycle. Not sure
how to fix
> this? I do not see any parameters to lengthen the record time. Pec is turned off and I'm using Predictive
Pec in
> PHD2, but hoping this can be fixed?
>
> First Ha image of the Cygnus Wall just came in!
>
>

I encountered the same problem as you report: the Gemini-2 PEC training acquisition time is broken. The internal
PEC that is advertisef to work in G-2 does not work. The only way to get a working PEC at this time is by
purchasing PEMpro, then use a PHD2 unguided log file fed into PEMpro to have it create the correct PEC file.

I reported the G-2 problem to Renew Goerlich who asked me to download certain files from the G-2, but I did not
have a CAT5 cable connection so I did not deliver the files requested. Bottom line: G-2 PEC does not yet work.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Thursday, June 17, 2021 8:56 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any reason not
to do this?

PCBoreland,

(What is your first name?)

I encountered the same problem as you report: the Gemini-2 PEC training acquisition time is broken. The internal
PEC that is advertisef to work in G-2 does not work. The only way to get a working PEC at this time is by
purchasing PEMpro, then use a PHD2 unguided log file fed into PEMpro to have it create the correct PEC file.

The PEC training in Gemini-1 does work. You don't need PEMpro if you have a G-1. You can use PEMpro if you
want of course.

I reported the G-2 problem to Renew Goerlich who asked me to download certain files from the G-2, but I did not
have a CAT5 cable connection so I did not deliver the files requested. Bottom line: G-2 PEC does not yet work.

Meanwhile I am happy to read your detailed reports on the 125:1 gearbox. I agree that PHD2 autoguiding will
correct the DEC and RA. It would be the same if tracking the sun or moon or a planet...you must use autoguiding.

And yes. The 125:1 vs 25:1 means that slewing will be somewhere like 5x slower. Yet it is the tracking perfection
that you are focussing on.

Best,
Michael





On Thu, Jun 17, 2021, 8:10 PM pcboreland via groups.io <pcboreland@...> wrote:


As was pointed out by David Partridge, it is possible to change out the gear box on just RA if one uses the
web interface to select the parameters. I installed the 125:1 gearbox earlier in the day, and have been able to
gather some initial data. As might be expected there is good and bad.

The Good. Unmoded, my Ra guided on average 30% worse than the Dec axis looking back over 6 months
of logs. With the limited short run tests done earlier this evening RA is now guiding 10 to 20% better than Dec. A
huge shift in performance. A seeming improvement of greater than 0.6 arcsec on 10 min runs. I'll be imaging in 90
minute blocks later tonight so will hopefully get data worth sharing, and this improvement holds

The Bad. 1. Ra runs slow. Over a 3hr period it fell behind the object a noticable bit. This I assume is
because the Ra tracking divisor is set to 89754 when it needs to be set 89754.2. I go not think this is a big deal as
guiding ought to handle this problem. 2. Pec training runs for just 48s. 1/5th of a worm cycle. Not sure how to fix
this? I do not see any parameters to lengthen the record time. Pec is turned off and I'm using Predictive Pec in
PHD2, but hoping this can be fixed?

First Ha image of the Cygnus Wall just came in!