Time out Issue and lock with SharpCap 4.0 and SharpCap 4.1 with camera Altair494C

[Corto46]

Hello,

I use this setup now since more than two years and last night I meet several issues. Impossible to do a single snapshot and my script sequence planned to do 83 frames stopped after 4 frames. After several tentatives to restart of Sharpcap and the camera , I was not enable to solve this issue.
This morning I restart the same configuration to do dark offline , without any issue.
Attached several log files to have your advice
Thank for your help
Christian

[admin]

Hi,

thanks for posting the logs - all of them are showing entries relating to timeouts from the Altair camera - basically SharpCap waits for the frame to arrive (the exposure length plus up to 10 additional settings) and when the frame fails to arrive, SharpCap writes it off as lost and tries again. This seems to be repeating.

I would suggest making some additional tests to try to track down the cause of the problem (and rule out some potential causes). A good starting point would be to treat this as a USB data transfer problem and troubleshoot accordingly (if the USB connection is not 100% reliable then the camera cam be detected and opened, but the large amount of data needed to transfer the image is usually sufficient to cause a problem, meaning that you get no images from the camear - very like your symptoms).

There is a step-by-step to troubleshooting this sort of USB problem here : viewtopic.php?f=18&t=349&p=1556#p1556 - by the end you will hopefully have tested with a different cable, difference PC and probably different software too - if there is still no sign of anything working then we might have to consider thinking that there is a problem with the camera.

cheers,

Robin

[Corto46]

Hi Robin,
Thank for your quick answser
Just to complete these informations
The Camera is an Altair294C not Altair494C as I wrote in the subject.
I did tests with two USB cables, one 3 meters and one 5 meters. These are specific cables supplied by Pierro Astro in France.
This morning I made 30 offline (in my house) darks with the 5 meter cable with the same shooting parameters as yesterday evening and I did not encounter any problems.
I also noticed when I encountered this problem that the camera looped permanently with restart cycles.

Question:
Can I using a USB2 port instead of a USB 3 to avoid these communication problems? I mainly take photos of the deep sky , time exposure are around 45 secondes.
Are there any specific settings to configure the USB connection in Sharpcap?

I have the AltairCapture software delivered with the camera , I will do new tests with this software.

I will keep you informed
Best Regard
Christian Mathieu

[admin]

Hi Christian,

you can use USB3 cameras with a USB2 port (usually), subject to the expected slower frame download rate. Just now and then you might hit issues as sometimes the power available on USB2 may not be enough to power the camera. If the camera has separate 12V power, make sure that is connected.

My experience is that USB3 cables become unreliable somewhere between 3 and 3.5m length - longer cables can work with an active repeater in the middle (basically a mini hub), or if they convert USB to some other data flow at one end and then back at the other. Also, two shorter sections with a hub between will likely work. It doesn't really matter how much you spend on 'high quality' cables - the issue with USB cable length is not a signal degradation one, it's a timing related one linked to the time taken for the signal to travel the length of the cable and back. For USB2, cables up to about 4.5m seem to usually be OK.

cheers,

Robin