Zwo ASCOM driver caused capture frame drop

[ffgoas]

I have been doing a bit of planetary work lately, trying out the planet sharpening and stabilization. I had the ASCOM drivers loaded for the ZWO focus motor. It limit the capture to 79.x fps. FireCapture would run the same frame rate with no drops. Never noticed it before so I started trying older versions of SharpCap and then ZWO drivers. Turn out it was ZWO ASCOM V6.5.24. Going back to V6.5.2 cleared the dropped frames up. I was testing at 3.2 ms and 400x400 image with a ASI678MC on a Beelink SER5 Ryzen 7 5800H.

[admin]

Hi,

how is the focuser connected via USB back to the computer? If something like this is happening, it seems quite possible that the small but regular USB traffic to/from the focuser is interfering with the camera data transfer. Try bringing the focuser USB back to the PC on a separate port (and ideally not on one next to the camera - often adjacent ports may have an internal hub).

Also, there might be some possibility of an adjustment to the camera 'Turbo USB' setting helping.

cheers,

Robin

[ffgoas]

I guess I was not very clear. I have it working at full speed with the older driver.(V6.5.2) My test would run at ~255 fps. Right now there are only 1 or 2 dropped frames at the start of capture. Supports 2-3ms frames. Very fast but sometimes the planets need it.

New driver V6.5.24 results in 2 of 3 frames dropped unless you are running a 15ms frame or greater. limited to 79fps.
Only the ASCOM driver for the focuser was changed.

This is a busy set up with a Meade10in SCT / ASI678MC and a Askar 230 (50mm) / ASI533mc all run on mini computer. All on EQ6-R Pro. I connect with remote desktop so is stays outside and I am inside (warm).

Just wondering what ZWO changed in their update.

Thanks!
Brian

[admin]

Hi Brian,

yes, that was pretty much how I understood it - the new focuser driver is somehow interfering with the frames from the camera causing a lower frame rate. I guess the options you have are

1) roll back the ASCOM driver and stay rolled back to the old version to avoid whatever gremlin has been introduced to the latest version
2) report the issue to ZWO and hope they fix it in a further ASCOM driver update
or
3) attempt to mitigate the issue at the camera side to see if you can find a way of avoiding the problem

The last point was really where my suggestions were aimed - some educated guesses on things that might - just possibly - have a positive impact and help reduce the frame rate drop caused by the focuser ASCOM driver change.

cheers,

Robin