ASI174mm longer exposure problem

avdhoeven

I own an ASI174mm and try to use it for guiding. Now I encountered some strange behavior. When I use my asiair with my camera and I set exposures >1 sec I get an error message that something could be wrong with the cable/camera etc. because it seems to be timing out.

I replicated this behavior with Firecapture and encounter the same problem then on my computer. As soon as I set the exposure to 1 sec the problem is solved and it works flawlessly, both in the Asiair and in firecapture.

When I try to do the same with AsiCap on my macbook I don't encounter the problem and it just takes the longer exposures.

Does anybody have an idea what could be going on? As it happens on 2 separate devices somehow I don't believe it's a driver issue, but on the other hand Asicap doesn't show it, so I'm a bit stuck. I'm using the Asiair v2.0 software, and I'm pretty sure that before on older versions it worked also.

Hope somebody has a solution for this.

Tech@ZWO

avdhoeven Did you try different USB cables?
Does it work fine in ASIStudio-ASICap？

Please also submit the log in the ASIAIR(ABout -> bug report) after you reproduce the problem, we will analyze it, thanks.

avdhoeven

Just a small addition. Asicap goes up to 3 seconds, but >4 seconds I also get problems and no images are downloaded anymore.

avdhoeven

Tech@ZWO I will do this later on. It works in Asicap up to 3 seconds, but after that I also get errors.

Tech@ZWO

Tech@ZWO We checked the log, but didn't find the exposure command, can you reproduce the problem and upload the log again?

avdhoeven

avdhoeven I've just uploaded the logs...

avdhoeven

avdhoeven On all my mac apps and the asiair it can't go longer than 1 second. When I use it in my Windows virtual machine it just takes longer exposures without a problem. Can't get a grip on it. I ordered a new cable, but somehow I don't think that is the issue.

I just installed asistudio on my windows virtual machine and I can perfectly do long exposures. Doing the same on my mac version of asistudio and I get exposure failed when longer than 1 sec. It seems to be some issue with the mac driver, and probably the same issue is valid for the asiair.

w7ay

avdhoeven I ordered a new cable, but somehow I don't think that is the issue.

The fundamental issue is not the cable, but the USB port in the camera. The USB ports in ZWO devices don't appear to be designed with enough engineering margins (voltage, frequency and temperature).

If that is the problem with your camera, by "tuning" with different cables, the ports could often be coaxed to work.

If you are using the USB cable that came with the camera, try and replace that with a good cable that is just long enough to connect your camera to the ASIAIR. Find a cable that advertises 20 AWG conductors for the voltage and ground pair. Do not be tempted by thin cables. And certainly do not use cables that are unnecessarily long to require them to be folded or coiled -- coiling a cable causes all sorts of problem with unshielded data pairs.

ZWO keeps recommending that people try with different cables, without admiting that the root problem is that their USB interfaces are not designed with sufficient margins to handle all USB cables.

Chen

avdhoeven

w7ay Thanks! I have ordered a cable from Pegasusastro with 28Awg power and 24Awg data, so hope that will help.

w7ay

avdhoeven 28Awg power and 24Awg data

28 AWG is way too thin to carry power. 24 AWG for data is fine as long as there is no ground loop.

Just browse through Amazon or electonic parts suppliers like Mouser or Digikey. Buying cables from a boutique store is just throwing money away for something that that are just rebranding.

Chen

avdhoeven

w7ay I swapped the values I see now 🙁 It was 24 for power and 28 for data... It's from a premium astro supplier here, so if it's bad I'll return it.

w7ay

avdhoeven It was 24 for power

That's still a little thin, but should be OK with a small sensor like the ASI174.

I just did a quick look at Amazon and found even a USB 2 cable with 20 AWG; so they do exist. In fact, most of the long USB cables at Amazon have 20 AWG power wires.

Chen

avdhoeven

Tech@ZWO I'll see how to do this later. Strange thing is I did an exposure and it gave me the failure, but the exposure was in the guide module, so maybe that went wrong? I'll see what I can do.

avdhoeven

I have uploaded a new log. I now also have tried the ASI174mm as main camera and also got an error when doing an exposure longer than 1 second.

I already have switched the cable, but this didn't change the problem 🙁

Basically this is what I see now:

On the asiair I can't take images longer than 1 second with my ASI174mm
On my macbook using ASIstudio of firecapture I can't take images longer than 1 second
On my macbook using Nebulosity I can take images with any exposure without a problem
On windows in a virtual machine on my macbook I don't see issues and can take any exposure time.

I just don't get a grip on it. Could maybe be some driver issue? Hope @Tech@ZWO can find anything in the new log.

Tech@ZWO

avdhoeven Got it, thanks.
Is it possible for you to do more test? connect it to the USB 2.0 port on the ASIAIR, then try long exposure, will it work?

avdhoeven

I'll do that! Never realised there are usb 2.0 and 3.0 ports. I will see if that makes a difference.
Thanks!

avdhoeven

avdhoeven I tried with all 4 ports. No difference unfortunately...

Tech@ZWO

avdhoeven If THE EXPOSURE failed problem can be stably repeated, your camera needs to be shipped back for repair, please contact the seller for after-sales service.