Weird Phd2 graph

[Joeistotalycool]

I was calibrating phd2 with by belt Modded neq6 PRO, and the graph appeared to have lots of backlash. The graph then went back to normal afterwards. 

It really confused me, so does anyone have any idea what it was?

[Joeistotalycool]

Update - doing it for dithers too

[kens]

Its always better to post a guide log. PHD2 scales the guide pulses so they are rarely on the same scale as the lines so its hard to analyse from a screen shot. But if you assume the early corrections are about the same magnitude as the guiding error, then the later ones are quite small. Most likely they didn't actually move the mount due to backlash and the seeing was the dominant feature.

The latest dev version of PHD2 has an option to show the corrections to scale

[Joeistotalycool]

On 06/08/2018 at 12:52, kens said:

Its always better to post a guide log.

Here are the guide log(s)

The 000240 is before i did a meridian flip and when i first started getting the issues

The 014836 is when I let it run for a bit, after a few attempts to get it working. The ra spike near the end was me accidently shining my torch down the guidescope

PHD2_GuideLog_2018-08-06_000240.txt

PHD2_GuideLog_2018-08-06_014836.txt

[kens]

That doesn't look so unusual. There is a lot of apparent backlash but the belt mod does not remove the backlash - you still have the worm and ring gear engagement which you may be able to adjust further.

Use the Guiding Assistant to measure your backlash. I estimate about 140 arcseconds of backlash which is not supported by the dec guiding in general so could be a balance issue as well.

The only other thing to look at is your aggression on dec. It is set at 0.4 so the backlash would take some time to correct. I see you increased it later. Also your MinMo is low at 0.05 so you would get more dec reversals than you want. Try Resist Switch algo and raise the MinMo

The backlash could be caused by the meridian flip putting the worm in a backlash situation just after the flip

At 2:16 it appears that the dither caused another backlash situation. 

[spillage]

Have you tried the new low-pass ZFilter guide algorithm in the development version of phd2. So far so good for me. But as @kens has mentioned manually remove as much backlash as possible both in adjusting the worm plate and the worm bearing. I also found balance as @Thalestris24 has pointed out to me before really helps. Not on my window pc so cannot view your logs but your images show that your scope may be south heavy.