Re: Strange behaviour

Roland Christen

Hello Stephane,

You can easily determine if the encoders are causing this by simply disconnecting the encoder box from the CP4.
One question I have: Did this occur when you had the CP3 attached to your mount?

Finally, it will not do much good to ask this on the user group since it is a technical issue. It would be better if you directed an e-mail to Howard at AP. Email: howard@...

Howard will be able to link to your CP4 and check the parameter settings of your mount. probably a simple adjustment is all that is needed. Don't try to fix this by doing anything with the gear mesh or balance.


-----Original Message-----
From: Stephane CHARBONNEL scharbonnel949@... [ap-gto]
To: ap-gto
Sent: Mon, Jul 3, 2017 4:47 am
Subject: [ap-gto] Strange behaviour


I will try to explain my observation in english.
I use GTO CP4 on 3600GTO mount with RA / DEC Encoders turned at ON with APAE v2.0. This observation can be seen with or without APCC. So it is not an APCC problem.

In Fact, if my mount is very well balanced (current has about the same value towards East or West for a slew), I can observe big oscillations of my mount after a pointing, more and more effective towards +/-6 hour angle (where mount is mechanically well balanced). This is observed at x600 and effectively not at x12. So, at very low speed (little corrections) there is no problem and the contact is always exist. But at high speed, I think encoders on RA axis want to correct too fast just after a pointing so the correction is violent and the system enters in oscillations. When oscillations has begun, there is oscillations also on DEC axis.

I have found two manners to correct this :
* A strong imbalance but it is not a sustainable solution and the problem exists at hour angle around +/-6H.
* I remesh the worm gear (I found it is difficult for me ( ;-) because I don't know when I must stop pressure) and current has considerably increase and is very different following the direction even my well balanced mount (when I realize a slew, I have 1.3A towards West and 3.1A towards East). But at this moment, I haven't oscillations whatever the position of pointing.

So, I would like to know if I must keep a worm gear strongly remeshed as this or if you think it is because RA Encoders want to correct too fast just after pointing for my 3600GTO with encoders.


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