Hello!
We just installed our new ASI2400MC Pro on our scope (17 inch Planewave CDK-400) and was trying to take flat images and it seems SharpCap kept locking up or running extremely slow at best. We usually use 2x2 binning and was setting up the flat field images and it was running so slow I couldn't get a good histogram setting. When trying to run the Flat's utility it finally did run, but it would only save an image now and then between a lot of dropped frames. Finally done, but accidentally saved as .png instead of .fits. Tried starting over but then it didn't save anything.
I know flats are very short images, and wondering if the file transfer rate is just too slow for our setup? We have about a 30-ish ft long USB cable to the scope in the observatory and it's worked great for our older ASI071MC Pro, but when swapping for the new camera, it's giving problems.
I tried playing with TurboUSB, framerate...etc. and other settings there, but not sure what that does or if that's the cause or not.
When I reduced the resolution down a bit, it was more responsive.
Our computer is good, it's new with plenty of memory, CPU and all that.
Any ideas?
Thanks!
Tom - Door Peninsula Astronomical Society
www.doorastronomy.org
ASI2400MC Pro - images too large for our USB?
-
admin
- Site Admin
- Posts: 13349
- Joined: Sat Feb 11, 2017 3:52 pm
- Location: Vale of the White Horse, UK
- Contact:
Re: ASI2400MC Pro - images too large for our USB?
Hi Tom,
unfortunately it's almost certainly your USB cabling that is the root cause of the problem. To be honest I'm surprised that you got something like the ASI071 working reliably over that sort of length.
To work with a decent frame download rate, these cameras really need a USB3 connection. My experience with USB3 cables is that anything beyond 3.5m total cable length is unreliable (and lengths in the 3.0 to 3.5m range may or may not be reliable). USB2 is better - you can get much closer to 5m with USB2.
Now, you can of course add either hubs or 'active' repeater cables to go beyond this length (an active repeater cable is just a cable with a built in hub). They are usually OK, but not all hubs (or repeater cables) are created equal, so it can be a case of trial and error to get a longer cabling setup working.
Your 30' cable works out at just over 9m, so for it to work at USB3 you would need all the cables to be USB3 *and* to have two hubs splitting it up into rougly 3m lengths. And a following wind... You might get it to work at USB2 with just a single hub/active cable.
To dig a bit deeper into the reason - identifying the camera and sending it commands to do things like change the exposure only require a small amount of data to be transferred, so they will tend to work even if the cabling is not quite perfect. However, getting images from the camera transfers a large amount of data, and if any data is corrupted during that process the whole frame is lost (since while there is error detection, there is no error recovery).
As a first step, try connecting the camera direct to the PC with the cable that came with the camera (probably about 1.8m). Verify that set up works, then slowly add more cable extensions/hubs/active cables, verifying operation at each step. You may find that you can get far enough to be useful, or you may find that the best approach is to move the PC closer to the camera.
Hope this helps,
Robin
unfortunately it's almost certainly your USB cabling that is the root cause of the problem. To be honest I'm surprised that you got something like the ASI071 working reliably over that sort of length.
To work with a decent frame download rate, these cameras really need a USB3 connection. My experience with USB3 cables is that anything beyond 3.5m total cable length is unreliable (and lengths in the 3.0 to 3.5m range may or may not be reliable). USB2 is better - you can get much closer to 5m with USB2.
Now, you can of course add either hubs or 'active' repeater cables to go beyond this length (an active repeater cable is just a cable with a built in hub). They are usually OK, but not all hubs (or repeater cables) are created equal, so it can be a case of trial and error to get a longer cabling setup working.
Your 30' cable works out at just over 9m, so for it to work at USB3 you would need all the cables to be USB3 *and* to have two hubs splitting it up into rougly 3m lengths. And a following wind... You might get it to work at USB2 with just a single hub/active cable.
To dig a bit deeper into the reason - identifying the camera and sending it commands to do things like change the exposure only require a small amount of data to be transferred, so they will tend to work even if the cabling is not quite perfect. However, getting images from the camera transfers a large amount of data, and if any data is corrupted during that process the whole frame is lost (since while there is error detection, there is no error recovery).
As a first step, try connecting the camera direct to the PC with the cable that came with the camera (probably about 1.8m). Verify that set up works, then slowly add more cable extensions/hubs/active cables, verifying operation at each step. You may find that you can get far enough to be useful, or you may find that the best approach is to move the PC closer to the camera.
Hope this helps,
Robin
Re: ASI2400MC Pro - images too large for our USB?
Thanks Robin,
That's very helpful. Yeah, I figured it was probably loss from the long USB run we have. I did replace one of the cables with a "boosted" USB that has a power dongle pigtail. We did have an QHY128C (which we are selling since the ASI is so much less trouble!) that only worked with the new cable. Interesting you say it would be better with USB2, but I can certainly see that.
I figure that the time the data is sent to the computer the next image is already backing up behind it (to put it in simple terms!) then add in the control commands, we have a bogged down mess.
Thanks for the info and confirming my suspicions, we'll do some experimenting with cables, boosters, hubs...etc. and go from there.
Thanks for the work on SharpCap also, it's perfect for public outreach, and we show images on our 80inch clubhouse TV. Great for those slightly cooler Wisconsin winters too.
Tom
That's very helpful. Yeah, I figured it was probably loss from the long USB run we have. I did replace one of the cables with a "boosted" USB that has a power dongle pigtail. We did have an QHY128C (which we are selling since the ASI is so much less trouble!) that only worked with the new cable. Interesting you say it would be better with USB2, but I can certainly see that.
I figure that the time the data is sent to the computer the next image is already backing up behind it (to put it in simple terms!) then add in the control commands, we have a bogged down mess.
Thanks for the info and confirming my suspicions, we'll do some experimenting with cables, boosters, hubs...etc. and go from there.
Thanks for the work on SharpCap also, it's perfect for public outreach, and we show images on our 80inch clubhouse TV. Great for those slightly cooler Wisconsin winters too.
Tom
Re: ASI2400MC Pro - images too large for our USB?
This is one of the cables we are running. I forget if it goes to the camera or the hub, but we'll string this across and see what happens and then tuck in out of the way once we find a combination that works. https://www.amazon.com/gp/product/B087L ... UTF8&psc=1
Re: ASI2400MC Pro - images too large for our USB?
I use a 10 meter / 33 ft cable over here. It's also active but it has a small, extra powersocket and adapter at the telescope end. Maybe that's the bit of "umph" the connection needs?tegwilym wrote: ↑Mon Jul 03, 2023 8:27 pm This is one of the cables we are running. I forget if it goes to the camera or the hub, but we'll string this across and see what happens and then tuck in out of the way once we find a combination that works. https://www.amazon.com/gp/product/B087L ... UTF8&psc=1
Menno
-
admin
- Site Admin
- Posts: 13349
- Joined: Sat Feb 11, 2017 3:52 pm
- Location: Vale of the White Horse, UK
- Contact:
Re: ASI2400MC Pro - images too large for our USB?
Hi,
the whole USB extension lead thing is a bit of a minefield... As I understand it, the limitations on USB cable length are related to timing issues (propogation times along the cable and back) rather than attenuation of the signal, so anything running the USB protocol over the wire will need a repeater every 3m to 4m or so. There are also things that run the data over an alternative protocol along the cable with to/from USB converters at each end (USB over Cat5). Some people get these things working nicely, some fight with them for ages with no success. It probably also depends on the camera brand/model too, so even copying the success of someone else may not work unless all the kit is the same.
There's a lot to be said for putting a PC on the mount itself and connecting to it with Cat5e networking. Short cables to the camera and other hardware are a win. I have a Beelink AMD 'NUC' sitting on my desk that is about 5" by 4" by 1.5" - it's pretty good apart from the SSD being slow once it has filled the 50 or 60Gb that it allocates for SLC write cache. Oh, and the fact that it shuts down instantly when I plug certain cameras into the rear USB ports! (They work in the front ports - presumably it's not handling USB power overload very well). A genuine Intel NUC will be more expensive, but less quirky...
cheers,
Robin
the whole USB extension lead thing is a bit of a minefield... As I understand it, the limitations on USB cable length are related to timing issues (propogation times along the cable and back) rather than attenuation of the signal, so anything running the USB protocol over the wire will need a repeater every 3m to 4m or so. There are also things that run the data over an alternative protocol along the cable with to/from USB converters at each end (USB over Cat5). Some people get these things working nicely, some fight with them for ages with no success. It probably also depends on the camera brand/model too, so even copying the success of someone else may not work unless all the kit is the same.
There's a lot to be said for putting a PC on the mount itself and connecting to it with Cat5e networking. Short cables to the camera and other hardware are a win. I have a Beelink AMD 'NUC' sitting on my desk that is about 5" by 4" by 1.5" - it's pretty good apart from the SSD being slow once it has filled the 50 or 60Gb that it allocates for SLC write cache. Oh, and the fact that it shuts down instantly when I plug certain cameras into the rear USB ports! (They work in the front ports - presumably it's not handling USB power overload very well). A genuine Intel NUC will be more expensive, but less quirky...
cheers,
Robin