Autofocus Lockup

I’m using and I had an initial problem where it was averaging a bad temperature from the focuser, hence I was getting a lot of autofocus runs. A new driver for the focuser was released about a month ago (USBfocus) that actually addressed this issue and that seemed to fix the problem, but another cropped up…

On two nights, I had a problem where SGPro would “lockup” during an autofocus run. This was due to the focuser’s ASCOM driver throwing an exception when it was told to move. I’ve sent the relative part of the ASCOM log and the SGPro log bits from around the time of the fault to USB focus and they said, it is still a beta driver and there are still some problems with it, so I’ll fall back to the older one.

However, what concerns me is that SGPro kept in the autofocus loop for over three hours waiting for something and my scope was staring at my house at sunrise still trying to autofocus. Fortunately the lockup occurred after the meridian flip or it could have been interesting. I know that if the filter wheel does not change in a certain amount of time, SGPro will abort and run the end of sequence, parking the mount, etc, but does it have the same fallback for focuser problems? In the morning, I stopped the autofocus run and SGPro hung up and I had to use the task manager to kill it.

What this post is about is I know there is a problem with the ASCOM driver for the focuser which is not an SGPro issue, but if SGPro gracefully aborts the run if the focuser causes problems such as when there is problem with the filter wheel. In some cases, just a simple disconnect/reconnect clears it,but if I have to kill SGPro from the task manager or it hangs in the autofocus loop until I kill the system, then I’ll lose quite a bit of sleep.

Attached are the logs:



The problem occurred around 08:38

Frank Z…


We do have a safety mechanism around focuser movement. I looked at the code and I think I spotted an area where it is broken… It will be out in the next beta.


I have the same problem, but cant seem to find a driver for USBfocus that works, could you share the one you use?
I wish there was an option for me to use another autofocuser, but there’s no other ready made solution for my focuser…not that the USBfocus solution was ready either because most screws were missing and the linkage between the motor and focuser didnt fit, it was too large.
USBfocus promised me the parts needed several times both through the seller and when contacting them directly, but i never saw any parts so i bought them myself.
Not finished product, bad customer service, bad software…Not really impressed with USBfocus :frowning:

I have been using ASCOM 2.51 and that seems pretty stable, short of the occasional 100C temp reading during focus runs which before were not even noticed. It is on their web site and they call 2.6 still in beta. It’s the summer holiday in France, so I got a reply to my e-mail about the problem but nothing yet until the end of the month. The Window system driver is also on their website and I have no issues with that. The only thing I don’t use is the backlash comp on their driver…I use SGPro for that. I’m using Windows 7 Home Premium 64 bit.

I picked up another coupler from McMaster-Carr to suit my setup. They have a range of them from the 6mm shaft that the USBFocus motor uses to others (1/4 inch for my AP155 and 5 mm for my AT65EDQ if I remember correctly). Not cheap and their shipping is on the high side (Mc-Carr), but they have it all.

I picked up a heavy duty ver 3 for my 4 inch focuser equipped AP and use the regular focuser v2 for the AT65. I made a heavy duty bracket for the AP155 as I needed a way to stop the wobble of the pinion block and it works fine, but any focus controller using the stock bracket (including AP’s bracket) would have had the same problem.

I know that Vincent of USBfocus said there is a more stable version of the V2 firmware and will replace my v2 controller for shipping costs, but I haven’t got around to the swap yet…one of the disadvantages of getting stuff from overseas.

It’s works fine for me and has been reliable.

Frank Z…

Thank you.
That driver works, but i’m still struggling with it, sometimes the focus position is reported totally works and ends autofocus. The reported value is missing a number so a real value of 1543 could be reported as 154.
Other times SGP locks up while trying to move the focuser, not sure if the problem lies with the driver or in SGP, but i guess it’s because of the driver problems and SGP not handling the problem well.

I think i’m gonna try to change the pin configuration on the plug for the motor so it can be used with another focus controller