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PHD2 Guide rate/speed pulse setting

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#1 gfunkernaught

gfunkernaught

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Posted 25 May 2020 - 06:58 PM

With the AVX, I experience an issue where if I send an RA slew command and a speed setting of 6, in one direction, the mount will continue to drift in that direction.  It looks like a balance issue.  Sometimes its east, others west.  If I change the slew rate to 3 and then send the command, the drift decreases significantly and eventually stops.  So if I am trying to frame and center, I can account for this offset and use a speed of 3 to center.  It is a workaround that I am happy with.  Now PHD2 sends RA correction pulses which cause the same issue.  I can see it in the graph where the RA line is a very jagged, triangle shaped waveform with an error of around 2.5".  So it looks like PHD2 sends an RA correction, mount drifts, then sends another correction in the other direction, then the cycle repeats.  Does anyone know of a way to change the speed or intensity of the RA pulse commands?  Do I lower aggressiveness?  I increased hysteresis to 15 and it helps, but I can still the issue occur based on the graph.  I've tried east balancing on both sides of the meridian, where I either lower or raise the counter-weight.  BTW my payload is about 17lbs and my counter-weight is 17lbs.  I first noticed this issue using the stock 12lbs counter-weight all the way down and it prompted me to think well maybe I need more weight on the bar to balance everything out.  Tonight looks promising so I am going to work on it some more, with both the 12lbs and 17lbs weights.  Note that actual guiding performance doesn't seem to be hurting my images much, but it would be nice to fix this guiding issue.  I get OCD sometimes.  Thanks!


Edited by gfunkernaught, 25 May 2020 - 07:01 PM.


#2 GrafikDihzahyn

GrafikDihzahyn

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Posted 27 May 2020 - 10:05 AM

Hey gfunk,

 

Are you using EQmod/direct USB or ST4 connection? Have you run the guiding assistant and let it run for 10min or so? Cleared the backlash in your mount? Sorry, there are a lot of variables.

 

Someone will certainly correct me if I'm wrong lol.gif , but I BELIEVE you should have the speed setting at .5 -1 sidereal rate for PHD2's guiding. It could be mount dependent I guess? When I was having issues with PHD2 I created a new profile, deleted the old one, and let the guiding assistant make all the changes I had fiddled with.

 

It wasn't until I re-meshed my worm gears and got rid of the backlash, that I could get PHD2 under 1" RMS. If your clutches on your mount are engaged, can you move either axis at all? It's usually just a slight wiggle like something is loose.



#3 gfunkernaught

gfunkernaught

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Posted 04 June 2020 - 04:26 PM

Yeah I know I threw out a lot to unpack there. So I use ascom guide via USB. I did run the assistant and it reconfigured the settings and seemed to help. That sidereal speed setting, should I set that in phd2 or in my mounts configuration? In my case CPWI. The last session my rms was around .85 until I slewed to another object, then I'd have to wait until it settled back to around that rms value. Although I did not see any issues with tracking in my images. I have to really tighten the clutches or else the mount will move when I'm adjusting or bump into my mount. By remesh the worm gear do you mean that special AVX backlash surgery or something else?


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