ZWO cameras timeout during downloads, especially if both imaging

[g__day (Matthew)]

I have a QHY-5IIL and three ZWO cameras running of a laboratory power supply (big and beefy). These cameras are all connected to a powered Mbeat 7 port high speed hub (4 high speed USB 3 ports and 3 USB2 ports) individually toggled on or off. This in turn is connected by a 3 metre high speed USB3 cable to a new quad core PC with two USB3 ports. My challenge since upgrading the PC in my astro lab is downloads from my two ZWO imaging cameras can slow or timeout occasionally - much more likely if both are running, whether or not the QHY or 120MM-s are running as auto-guiders into PHD or PHD2 respectively.

For imaging I run a ZWO ASI1600MM-c plus 7 port filter wheel into one of the high speed ports, a ZWO ASI071MC-c Pro into another and a ZWO 120MM-s from a OAG on the 1600MM-c into a third USB3 ports. The QHY and focusers run into the other USB2 ports


All these cameras are limited in the driver to only use 40% of available bandwidth (5 Gbps). I note the image download timeouts seem more frequent on my newer, more powerful astro-lab PC than my older dual core PC that used to struggle with the load. I very, very seldom take video using Sharpcap. Both cameras are used 99% of the time to capture unbinned 2 - 6 minute subs. So I wouldn't expect bandwidth load to be that high - a 30MB file (if binned 1x1 ) or 7 MB binned 2x2 once every 2 - 6 minutes from each camera over a 5 Gb/sec pipe should be no issue.
So any idea what is going on? I generally control one camera from SGP and another from either The SkyX Professional Edition + Camera add on (as ASCOM cameras) or APT (latest release).


I am thinking of wiring another 7 identical port split high speed and USB3 powered hub off a 5 metre USB3 cable plus extender into the second USB3 port on my Astrolab PC - giving two x 5 GBps lanes to my peir. I wonder if it is a driver or Windows 10 configuration problem (Power settings are to never power down the USB port - only ever the monitors - as I run everything remotely over gigabit cat 6e cable into gigabit switches from my house 30 metres away over TightVNC.


Much appreciation if anyone can suggest what is going on and how to best avoid / correct it!

[glend (Glen)]

Honestly I think you have far too much going on, and your relying on one cable. I always used a powered USB3 extension cable from my Mbeat hub to my laptop, never had any problems. I never used the on camera hub, but cabled the guide camera directly to the Mbeat. I used SGP. And oh by the way I never trust anything astro running on WIN10, my stuff still uses my trusty WIN8 system. I would suggest you split into two system, Good luck.

[lazjen (Chris)]

I am going to bet it's the cable length, even though you've got extra power. I've been having similar problems recently, and I'm now using a dedicated USB3 port on the laptop to connect to the ASI1600 with a much shorter cable (I've got the FW and guide camera plugged into the ASI1600 - the other USB items go via Mbeat hub). So far, it seems to be working, but I haven't had enough time running it to be sure.

[Camelopardalis (Dunk)]

Try adjusting the USB speed in the driver. Drop it to 40 to start with and check you can reliably get images down the pipe.

[g__day (Matthew)]

Hi guys,


Yes the USB speed in all the drivers is set to 40%. I just added a 5m USB3 extension cable plus repeater to another USB3 port on my PC. It could see USB drives easily but not either of my primary USB3 cameras when directly connected.


So I dropped in another Mbeat 7 port powered hub to this new 5m USB3 cable plus repeater and connected one of my USB3 cameras to this hub - it instantly saw the ASI071MC-c camera. Next I did run of dark frames for five hours; APT controlling the 71MC-c and SGP controlling the ASI1600MM-c. APT ran fine, SGP dropped out once at the start of the sequence, so I aborted the process, from SGP software disconnected and reconnect the camera and restarted the run and it has been running fine for the last two hours.


So my thoughts are beyond ample power to the ZWO to cool them down - they might need a lot of power from your USB3 cable to connect and download effectively. I don't know the level of per that is required over USB3 for them to be reliable - but I ponder adding to many USB3 devices to this powered USB3 hub drops the power down below what is required for the camera to be stable under downloads!


So power sufficiency over USB3 cable seems to be strongly linked to their reliable performance.

[glend (Glen)]

In my experience, ASI cameras perform best when directly connected to the laptop on a dedicated USB3 port, and when a powered (5v) extension cable is used for that run. Keep guide camera traffic off that cable, send it via the Mbeat to another port.

[Startrek (Martin)]

I threw my MBeat 7 port powered hubs in the rubbish bin , nothing but intermittent trouble
Bought a 4 port USB3 Startech powered hub , no issues at all running USB3 and USB 2
Also there is a limit with traffic on these hubs especially USB3, try to connect your USB3 devices direct to laptop (USB3 port) or PC and leave the USB2 devices for the hubs
My 2 cents .....

[Camelopardalis (Dunk)]

No solution from me, unfortunately, but in the early days with my 1600 I found similar behaviour from my Mbeat 7-port USB3 hub (the triangular ended one).

I remedied the problem by buying a 5m USB3 cable and that's what I've used ever since to connect the camera to the computer. No issues since, and I can use up to USB speed 100 - although I tend not to as I see extra pattern noise at that speed (non-Pro model).

[g__day (Matthew)]

I have asked ZWO on both their Facebook forums and e-mail to their support team what their suggestions are.


Stay tuned!

[g__day (Matthew)]

Resolution so far in case anyone else has this issue.


APT detected my ZWO ASI0120MM-s was dropping out every minute for 5 seconds. Somehow this seems to have cause a problem with my other USB3 cameras on that or other hubs.



Switching the guide camera to a USB2 connection on the MBeat powered hub worked. Then today I put another powered USB3 hub (Targus this time, not MBeat) into play and connected the Guide camera to that - all stable so far!