1. The training during the countdown to 0 is not needed. It is suggest so you get use to correcting and get settled.
2. The counter goes from 0 to 200 (and yes initially it was 240).
3. Your comments 1 to 3 are correct.
4. Your comment four, there are 45 pulses per second (and over 8 minutes or 480 seconds this is 21600 pulse which is the nominal value shown after the training), so your 108 is correct.
5. Your guiding will increase or decrease the number of pulses in an interval. The LX200 saves the number of pulse actually needed in each interval. It totals these to get the final number displayed.
6. Your comment seven, the software actually 'averages' out the pulses over the 2.4 second interval so that the pulses are evenly spaced and the total count is as stored from training. There is no 'guess' as to skipping pulse which would provide irregular tracking.


This does mean that if you have a sudden tracking shift in a 2.4 second bin, then on the average before the shift you will be too fast (or slow) and after you will be too slow (or fast).


Ralph

Wayne Watson wrote:

> I've looked around at the MAPUG archives and Doc G's site and have a few questions about the details
>
> of PEC (RA) training.
>
> I recall some time ago that maybe there's a bug in the PEC s/w so that one should not wait for the
> counter to drop down to 0 before training begins. I believe the change in operation is that one
> should start operating the arrow controls immediately and follow it through zero and up to 240 (or
> where ever the s/w signals an end). Is that correct? Apparently older version of the s/w use the
> range from 0 to 240, and newer ones from 0 to 200. Is that correct?
>
> As for the operation of the PEC (RA) method, it looks like the following:
>
> 1. training goes over a 8 minute period
> 2. the software breaks up the 8 minute (480 second) period into 240 (or 200)
> intervals (I'll use 200 in what follows)
> 3. Each of the 200 intervals represents 2.4 seconds
>
> ( Continuing. Here's where I'm a little in doubt, so chime in if you want.)
>
> 4. 108 RA motor pulses are produced in a non-PEC trained operation to
> drive the RA motor westward to keep up with the westward moving sky
> (Now I'm on really weak ground)
> 5. When the PEC is trained, each operation of the eastward arrow requires the motor to stop, so
> effecitvely a pulse count is removed from the interval (bin). The implication that the RA
> motor only needs to stop is that the scope only needs to let the sky drift for the object
> to
> return to center. ---- Note that each pulse lasts 2.4/108 seconds
> 6. When the PEC is trained, each operation of the westward arrow produces a (additional) pulse,
> so a pulse is added to the interval (bin counter). (We are trying to keep up with a westward
>
> drifting sky by driving the motor westward.)
> 7. I think (!guess?) that when the s/w is about to execute the pulse commands for an interval it
>
> looks at the count for the next interval and tries to apply the number of necessary pulses
> evenly. Normally it would see 108, but suppose the count was 54, then it would pulse, stop,
>
> pulse, stop ... through the 2.4 second interval.
>
> The process outlined in steps 5 & 6 theoretically should produce 108*200 or 21600 pulses if all 200
> bins are summed, since there must be an equal number of east and west pulses (actually none in the
> eastward direction) if the object is to remain in the center of the (calibrated) eyepiece.
>
> Well, that's a bit of guess work on items 5-7, so chime in if you have other info to offer.
>
> --
> "We have nothing to sphere, but spheres themselves."
> -- Ms. Maxwell, My HS 3-D Geometry Teacher
>
> Wayne T. Watson
> Web Page: http://www.sirius.com/~mtn_view (Updated 6/21/2000)
> Imaginarium Science Museum:
> http://www.sirius.com/~mtn_view/imaginarium.html

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