Meade DSI IV cooler crashes SharpCap

[bobequus]

Hi,
When I use my Meade DSI IV (mono), it sometimes crashes SharpCap. It appears to happen when the cooler reaches the desired temp. I've sent in several of the bug reports that pop up. The first few times, only the camera was connected. I did get it to work with the 32bit version yesterday, but it crashed on that the next day. I also got it working today with a Solar capture. I had the scope, focuser, and filter wheel connected as well. It reached desired temp and held it for about 1/2 hour. Then it crashed. I know this camera has a lot of problems with the drivers. For instance, I can use it in APT and SGP, but cannot access the settings from within those programs. Hopefully someone may have found a work-around. Thanks in advance.
Bobby

[admin]

Hi,

Can you let me know which version of SharpCap you were testing with when you submitted the bug reports? I've had a look back through the reports for recent versions but haven't found any that seem to relate to Meade cameras.

Cheers, Robin

[bobequus]

Whichever is latest. 3.6086 I believe. (my astro laptop is packed right now.) BTW, how do I tell the difference between the 64 bit and 32 bit when they are running? The "about" splash screens are identical.
Bobby

[bobequus]

I reproduced the error on my desktop. Here is a screen shot. Same thing. Target temp 0. Crash when camera hit 0 or 0.2 below.

[bobequus]

Further info:
Installed 3.2.6121.0 (64 bit) on my desktop. Been running for several hours with no hiccups. Changed cooler temp several times, no crash. However, when using the DirectShow driver, the exposure slider is locked. One can manually put in numbers and the exposure will change, but they have to be the right number. For example, if the exposure is 0.49 and you type in 0.59, it will stay at 0.49. But if you type in 0.62, you will get 0.69. There are no thermal controls available with DirectShow as well.
Bobby

[admin]

Hi,

What you are seeing with a direct show drivers is pretty much expected – direct show was a mechanism that Microsoft created for controlling WebCams so there is no way to control things like camera coolers using direct show. It also has limited control over camera exposure and in some drivers it has no control at all. I certainly wouldn't recommend using it except as a last resort if a camera is not supported in any other way.

As to the error, it looks like the camera driver is giving an error when asked to tell SharpCap what the current temperature of the CCD sensor is – that's the sort of thing that should never give an error if the camera has a temperature sensor, so SharpCap was not set up to deal with an error in that location. I will see if I can put sufficient error handling around that part of the Ascom driver to ignore any errors – although that would mean that the actual temperature of the sensor may not update correctly, it would be better than crashing.

Cheers, Robin

[bobequus]

Thanks Robin, for the help.
I uninstalled SharpCap on my laptop and put the latest version (64 bit) on the machine. It started crashing SC from the start. Same as before, temp set for 0 and once 0 was achieved, it crashed. I tried changing USB cables, running through a hub, not running through a hub, etc. At one point, I tried changing the temp setting to 5C. SC got it there and no crash. However, when I connected my filter wheel and changed to a different filter, the preview froze. I tried a capture and 0 frames were recorded. No crash, though. Here's the weird part. I closed the camera and all the other stuff and opened the Meade in APT. No image. Said the camera was connected but nothing on Live View or when I took and exposure, it just said "busy". A reboot fixed that.
I will be doing more experiments today and post any results as they occur.
Let me just add, Robin, that I used SharpCap with an ASI183MC Pro and the program works flawlessly. Thanks for all your help.
Bobby

[admin]

Hi,

Hang on for the next version which may be able to fix the crash when the temperature gets to zero.

With the problem with the filter wheel I'm wondering if you are perhaps using both devices via a USB hub or similar? That's the thing that often prompts this sort of interference between two separate devices – they end up fighting for bandwidth on the single USB connection back to the computer and one or more of them can end up failing to work properly. If at all possible bring all devices back to the computer using separate tables to separate USB ports with no hubs involved. If you must have hubs then put low bandwidth devices such as focusers and filter wheels on the hub and gives cameras separate connections if at all possible.

Hope this helps, Robin

[bobequus]

I'll check that out. Currently, the imaging camera goes via USB3 directly to the laptop. Guide camera, focuser, and filter wheel are hubbed into a repeater cable, then into the laptop. Polemaster and mount are on a different hub into the computer. I'll start mixing and matching to see if anything changes. I've got one more open USB port and a USB-C (although I use that for my recording drive).
Bobby

[bobequus]

I changed the guide camera to directly into the laptop. No crash with hitting 'settings' on filter wheel. Also, the temp is working. I think it may have to do with the default setting of "0C". First I set it to +5C before it had a chance to hit 0C. Hit temp and held with no crash. Then I set it to -12C. Cooled down, went past 0C and settled at -12C. No crash, running for about twenty minutes so far.
Bobby