QHY600m Drop Packets when Gain 160 during Sensor Analysis

[smccully]

As mentioned in the subject, everytime i run sensor analysis in C2MS mode when doing gain calculations after dark frames when the gain is set to 160 packets are being dropped. Actually this happens during regular camera capture as well, but not in ASCOM connection mode.

[admin]

Hi,

The two things to check for this sort of problem are

1) USB cabling - if you are using USB extensions, hubs, etc, take them out and use a single cable direct from PC to camera (less than 2m length)

2) USB Traffic setting in the camera controls - try other values - lower typically gives higher frame rates, but can be less stable, so initially try a higher value

You could also try using the 'Force Still Mode' option to make SharpCap drive the camera via its still image mode rather than the video mode - this can sometimes help.

cheers,

Robin

[smccully]

This appears during the "Sensor Analysis" tool only, and it happens exclusively on these values only. Every other MODE has worked fine.

[smccully]

Just to follow up on this, with the MODE in C2MS and GAIN 160 all camera frames are being dropped. Changing the GAIN to something else and camera frames no longer drop.

[admin]

Hi,

Ok, this sounds like it is a bug with the QHY SDK relating to that combination of mode and gain - there certainly isn't anything in the SharpCap code that would give different behaviour for specific gains like that.

There is a new version of the QHY SDK that I need to bring into SharpCap in the next update (probably next week) - it's just possible that the update will fix the issue.

It's unfortunate that the gain that causes issues is one of those picked for the sensor analysis - right now there are ways to add gains to the analysis list, but no way to exclude a gain. Ideally, QHY would fix whatever underlying problem causes this issue with the camera rather than work around it, but that isn't always realistic. Let's see if the new SDK update helps and then consider a workaround.

cheers,

Robin

[smccully]

Thanks Robin that certainly makes sense,

while we are discussing the analysis tool have you considered adding a feature to the `Sensor Analysis` that would allow users to select the granularity for gain measurements. The QHY600 has drop-offs at gain 26 or 56 depending on which mode is being used. Selecting a finer granularity during the analysis tool would allow more measurements to show these drop offs a little better? Obviously would take longer to run, so the user could decide to use a finer granularity would be aware of this.


Sean

[Jean-Francois]

Hello,

I test my QHY600 camera. At gain 160, I have no dropped frame for all the modes.
Extended Fullwell 2CMS, 2CMS-0 and 2CMS-1 too (what that modes are).

I used SharpCap 4.1.11961 and QHY driver Beta_QHYCCD_Win_AllInOne.24.01.09.17.

Regards,
Jean-Francois

[admin]

Hi Sean,

regarding the custom measurement points, that can be achieved via the Python scripting console, using the command

Code: Select all

SharpCap.SelectedCamera.SetGainsOfInterestForSensorAnalysis([26,27,56,57])

Run that command after opening the camera but before running the analysis and the analysis will include the listed gains in addition to the range picked automatically by SharpCap. This allows you to find the cliff edges in the data if you know the right points (some brands of camera allow SharpCap to determine automatically the extra gain points to include - sadly not QHY though).

Interesting that Jean-Francois has no issues at 160 gain - perhaps different versions of the QHY driver or camera firmware?

cheers,

Robin