Re: Encoder vibrations

Ross Salinger

I use that particular scope and the first time I did and I saw it start moving I hit the abort button. I was convinced that I had done something terribly wrong. Once reassured that it actually was supposed to do that I can testify that it nails objects every single time.

I have no idea (seems like magic) how something that big can move that fast and stop accurately to within a few ticks.



From: SiTechservo@... [mailto:SiTechservo@...]
Sent: Monday, August 29, 2016 10:00 AM
To: SiTechservo@...
Subject: Re: [SiTechservo] Re: Encoder vibrations



Sweet!   I am not sure I have ever heard Dan state what he thought was the max tics per rev for a ServoII. 


It's obviously screaming fast!



On Aug 29, 2016, at 11:02 AM, westergren@... [SiTechservo] <SiTechservo@...> wrote:


Hi Chuck,

The 25 inch at TAI is using absolute encoders with 2^26 = 67,108,864 bits and slews at 5° per sec.  The Servo II handles it well.

Don W

---In SiTechservo@..., <candcshaw@...> wrote :

Wow, at 64,800,00 tic’s per rev, I would be afraid to cough near the mount!


What slew speed are you able to achieve?  The ScopeII controller reads the encoders very fast, but 64.8M is a lot of bits to swallow at a time!!




From: SiTechservo@... [mailto:SiTechservo@...]
Sent: Sunday, August 28, 2016 9:22 PM
To: SiTechservo@...
Subject: [SiTechservo] Re: Encoder vibrations



Hi Don,

The sensitive encoder is a renishaw 413mm diam. with a scale pitch of 20 microns.
64,800 lines X 1000 interpolation = 64,800,000 non-absolute. accuracy +/- .53 arc seconds
Tonic dual read heads

The other is a 255mm encoder @ 40,000,000 , but don't seem to be that sensitive.


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