On 4/6/2021 11:51 PM, Brian Valente wrote:
you can try TVC 10. if it's working well, you should see backlash amount decrease (but not be eliminated)
if it's too much your DEC will oscillate. it will be pretty obvious. just drop it by a point or two.
10 is pretty low. you could also increase it if you want to see more improvement. I probably wouldn't go past 25 for now
FWIW.....
I find that my GM811 DEC backlash as reported by PHD2 varies between something less than 200mS and about 1800mS depending on where I am pointing and possibly other unknown variables. Typical is around 1200mS.
I can set TVC to a non-zero value and reduce the PHD reported backlash nicely. In my case, TVC=10 seems to be a good number. But that runs the risk of reducing the overall backlash to (or below) zero depending on pointing location. If backlash approaches zero, the system can oscillate. This is especially noticeable at the start of a new session or after a slew because PHD2 may be attempting to compensate for more backlash than is currently present.
I have decided to use TVC=0 as long as the reported DEC backlash is less than 2000mS. PHD2 can easily compensate for that amount of backlash and the only observable effect is that on DEC reversals PHD2 appears to wait for the duration of the applied backlash compensation before beginning a new exposure.
Paul
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Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com
