PHD2 exposure incomplete message even though exposures DID complete
Ken Bates
A friend of mine has been having a problem with obtaining dark frames with PHD2 and asked me for some assistance. After looking into it, the problem appears to be computer related, but for the life of me I can’t figure out what the issue is; hence my request for assistance.
When she runs PHD2 to do dark frames, all goes well until the exposures reach 4.5 seconds. At that point PHD2 raises an error message saying that “After 16.0 sec the camera has not completed a 1.0 sec exposure… <etc>”. The interesting thing is that the error message references a “1.0 sec exposure”, even though all exposures prior to the 4.5 second one appear to have completed successfully. Doing the usual troubleshooting (changing USB cables, etc) has no effect, and she is unable to get a good set of dark frames.
She and I have nearly identical configurations (iOptron CEM40 mount, ZWO ASI 120mm guide camera, and Windows 10 Pro running on a Minix PC) so I connected her Minix to my system and tried dark frame calibration. When I did, the exact same error occurred, even though it was on a different mount, different guide scope, different USB cables, etc. Every hardware component the chain was different, with the sole exception of the Minix PC running PHD2. I checked all the drivers (ZWO ASI and ASCOM) and updated them to the latest version, and also deinstalled and reinstalled PHD2, but the problem persisted. If I substituted my Minix PC for hers, PHD2 dark frame calibration works fine. This definitely points to her Minix PC (and/or software) as being the culprit.
I looked at the PHD2 log files, but there was nothing there, so I’m assuming that dark frame calibration is not logged. Either that, or something is preventing the logs from being written. Guiding when imaging works fine; although the error message about being unable to download exposures continues to pop up. This makes me wonder why this message is coming up, since the images are clearly being downloaded and successfully used for guiding. I am attaching a PHD2 log file from her last imaging session, which shows a good guiding assistant followed by good guiding and good image capture. In spite of all this “goodness”, messages about being unable to complete exposures were still present.
So, any idea of what could cause an issue like this? Clearly something in the Minix, but having updated and/or reinstalled everything related to PHD2 with no success, I’m at a loss as to how to proceed. The lack of a PHD2 log file when doing a dark frame calibration and the message with an incorrect exposure time is also troubling. Any help or suggestions on what to try next (short of initializing the PC and reinstalling Windows 10) would be greatly appreciated.
Thanks in advance for any assistance,
Brian Valente
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bw_m...@earthlink.net
Hi Ken. You need to upload both the guide and debug log files for a session that demonstrates the problem. Everything that we need is logged. You’re probably looking in the guide log which won’t have any of this stuff because you aren’t guiding while building a dark library. Please use the log upload feature described here:
https://openphdguiding.org/getting-help/
Regards,
Bruce
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Ken Bates
bw_m...@earthlink.net
Ok, let’s start with the timeout problems during guiding. These are definitely errors, they are not illusory, and when they occur you have lost a guide frame plus the time it takes to disconnect/reconnect to the camera, start another exposure, and get the next camera image. On your system, using 2-second exposures, each of these errors means you go for about 30 seconds without guiding. The manual explains what the error means and lays out a testing methodology for tracking down USB-related problems (Trouble-shooting section). It is possible that the USB subsystem on this computer you’re using isn’t up to the job in terms of either bandwidth or power delivery. One thing you could try would be to use a powered USB hub between the computer and the guide camera.
The dark-frame problem is different. You are right that the error message is bogus in its reference to a 1-second exposure – I will fix that. But again, the error condition is real – a 4.5 second exposure request hadn’t completed in 16 seconds. We saw a number of these specific problems with ZWO cameras a number of months ago. It appears that the problem was caused by a mismatch between the ZWO SDK that PHD2 was using and the rev level of the ZWO camera driver. These problems stopped being reported when both software elements were upgraded. You should try updating to the PHD2 2.6.11dev2 release which has the latest version of the ZWO SDK. PHD2 will do this for you if you allow it to check for dev releases.
If you de-installed PHD2 at some point, you will need to be careful to re-run the new-profile-wizard with all the correct parameters, re-set the min-move values using the Guiding Assistant, etc. De-installation is rarely a good idea when trying to track down these kinds of problems.
Good luck,
Bruce
From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> On Behalf Of Ken Bates
Sent: Friday, November 18, 2022 9:37 AM
To: Open PHD Guiding <open-phd...@googlegroups.com>
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Brian Valente
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Ken Bates
Thanks for the information, Bruce. I did download, install, and run with dev2, but the problem remains. Also as I mentioned in the original post, I had updated all the ASCOM and ASI drivers, so that isn’t the issue.
Interestingly, the camera ran just fine with ASI Studio in both single frame and continuous (video) modes. To me this indicates that the camera is getting plenty of power from the USB port that it’s connected to. The camera is usually connected to the powered USB hub on the ASI 533 main camera, but I’ve also connected it directly to the Minix USB port, and the timeout occured on both.
Since things worked with the ZWO ASI app I dug a bit deeper. When I switched PHD2 over to using the ZWO driver, everything worked. So, the problem turned out to be using the (fully up to date) ASCOM driver instead of the ZWO one. Not sure that I understand why that is, but since things appear to be working, I’ll leave that mystery for others to solve. I knew that it wasn’t a PHD issue; it was just finding out what software on the Minix was causing the problem.
Thanks again for taking a look it this - much appreciated.
- Ken
bw_m...@earthlink.net
Yes, this isn’t a big surprise either. There have been a number of times when the ZWO ASCOM driver lagged their native driver. Since ZWO’s own products use the native drivers, I suppose they are considered to be the reference implementations. Since the ASCOM driver showed the same symptoms as the earlier version of PHD2, it may also be using an SDK that is down-rev. But that’s just a guess.
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