View Issue Details
ID | Project | Category | View Status | Date Submitted | Last Update |
---|---|---|---|---|---|
0001830 | CCdciel | General | public | 17-11-04 12:40 | 17-11-09 17:01 |
Reporter | han | Assigned To | Patrick Chevalley | ||
Priority | none | Severity | trivial | Reproducibility | always |
Status | resolved | Resolution | fixed | ||
Product Version | 0.9 | ||||
Target Version | 1.0 | ||||
Summary | 0001830: Temperature compensation working fine, only a tweak suggested | ||||
Description | I have tested the temperature control intensively in simulation and it works at desired. My problems are caused by slippage of my motor driven focuser fine knob. So I have to update the V-curve every few observing nights to compensate. So I can report code is fine and correct. While doing so, I have a suggestion to simply the code an almost futile amount having the same functionality. In procedure Tf_starprofile.doAutofocusVcurve the following line is used four times: // correct for temperature if AutofocusVcTemp<>NullCoord then newpos:=newpos+focuser.TempOffset(AutofocusVcTemp,FocuserTemp); Since temperature is a slow process this could be reduced one for vcsStartL and one for vcsStartR by reusing the calculated temperature offset (stored in a variable). I assume the AutofocusVCtemp<>Nullcoord is required if no temperature measurement or an old V-curve is available. | ||||
Tags | No tags attached. | ||||
|
Thank you, I change the code in rev. 622: https://sourceforge.net/p/ccdciel/code/622/ Do you think it is possible to make a correction for slippage? at least to request a new curve less frequently. Maybe store the last focus position and for the next focus operation correct the start position by the difference between this last position and the central position at the time the Vcurve was measured. |
|
Well that could be an interesting option. I have high quality Rack & Pinion (geared) 3 inch focuser but decided to connect the motor to the 1:10 fine knob which is not geared but relies on friction. It uses stainless steel bearing balls held in a brass housing and will have no hysteresis but will have a tiny amount slippage over time as a now can confirm. So I have the same problem as people with Crayford focuser which relies on friction rather then the geared Rack & Pinion. I could be an option "automatic slippage compensation." If the focus is reached satisfactory with a HFD close to the bottom of the V-curve it could calculated the difference of the expected calculated position and found solution and store this offset. See a proposed menu for Crayford focuser (and me) |
|
I add the slippage option in revision 630. But I add the option in the Autofocus tab because this is a Vcurve only option and the space you use in the Focuser tab is to set the backlash for the relative position focuser. https://sourceforge.net/p/ccdciel/code/630 |
Date Modified | Username | Field | Change |
---|---|---|---|
17-11-04 12:40 | han | New Issue | |
17-11-04 18:48 | Patrick Chevalley | Assigned To | => Patrick Chevalley |
17-11-04 18:48 | Patrick Chevalley | Status | new => assigned |
17-11-04 18:48 | Patrick Chevalley | Target Version | => 1.0 |
17-11-04 18:48 | Patrick Chevalley | Note Added: 0004226 | |
17-11-04 21:06 | han | File Added: slippage correction.png | |
17-11-04 21:06 | han | Note Added: 0004227 | |
17-11-09 17:01 | Patrick Chevalley | Status | assigned => resolved |
17-11-09 17:01 | Patrick Chevalley | Resolution | open => fixed |
17-11-09 17:01 | Patrick Chevalley | Note Added: 0004246 |