Some niggling issues

[TimC]

Hi,

 

I have been getting some usb resets lately and also some freeze ups. I have attached some logs and an error message to see if anyone can help diagnose the issues. I have invested a lot of time in balancing, but I accept that there may some imbalance in some axes that it is very difficult to absolutely correct.

 

Many thanks,

Tim

AutoslewLog.txt

ServomotorLog.txt

[TimC]

HI,

 

Had another ASA mount driver crash last night. Some nights go all night smoothly, others a ?random crash occurs. 

 

 Has anyone had time to look at my logs?? 

 

I will email ASA directly as well.

 

Regards,

Tim

[lukepower]

Hi Tim,

 

supposed that the balancing is alright, what I would check is:

• USB cables and hubs. Try to exchange them. I once had an active USB cable (for >5m distance, that is), and it was all trouble. SomeUSB hubs also cause problems if the input voltage drops too low (might happen during a slew)
• Power source of the mount: Just in case it might not be able to give enough power in every situation
• Mount electronics (kill me now ): I had a burned USB board in the mount which caused random errors, as during a slew the voltage input changes slightly (and too much for the now defunct hub).

I guess that's it for now... Hope it helps

EDIT: I had a look at your logs, nothing particular, except that Axis 2 is quite a few times at and over 5 Amps, that might be an issue...

Edited September 1, 2014 by lukepower

[GeorgeCarey]

I do not know what causes that error - I have never had it myself.

I had a look at your motor current. This is the graph:

[robertp]

Hi,

 

I also had USB-issues in the past and resolved them by trying different hubs, active extensions and USB-cables. It was mainly try&error as e.g. buying "industrial grade" hubs powered by 12V did not resolve some of the issues.

The USB cable provided with the Lodestar guider seems e.g. to be very high quality even though it is much thinner than the average cable. With that cable, I had stabel connections where other, shorter cables failed.

 

I just bought a small device that displays the voltage and current consumption of USB devices similar to this one:

http://www.amazon.com/BESTOPE-Charger-Doctor-Current-Voltage/dp/B00GC9I61I/ref=sr_1_3?ie=UTF8&qid=1409562071&sr=8-3&keywords=usb+voltage+tester

 

This might or might not help to better understand what's going on. Might be worth a try.

 

Best regards,

 

Robert

[TimC]

Hi Lukas, George, and Robert,

 

Thank you all very much. I will swap out the USB and see if I get some improvement. The power source is the one supplied by ASA, so I suspect that is OK. George, it looks like to me there is no current rise before the crash, so maybe it isn't the dreaded lack of balance gremlin. I will hope it is an inadequate USB rather than a fault. The last 3 nights have been run by CCDAP all night without another glitch, but the night before that the scope froze up after trying to point to the ground....!

 

Cheers,

Tim

[MarkS]

Hi Tim,

 

That DE current of ~4A looks very high to me - but I don't have experience with the DDM85

 

Regards,

Mark

[lukepower]

Tim,

 

it would be interesting to know if the fault happens in a specific position, i.e. the scope looking at a certain Az/Alt position in the sky, or slewing from/to there. If yes, then I would say it's imbalance. If not, go and get some USB cables to try out

 

Mark, 4 Amps are actually rather high, now with the 110kg beast well balanced my DDM85XL goes practically never over 2 Amps on either axis (but it used to go far higher )

[TimC]

Hi Mark and Lukas,

Thanks very much. So, if 2amps is more usual, than perhaps there is still an imbalance particularly in the DEC. The scope is an AstroOptik 0.5M Classical Cassegrain and it does weigh about the same at about 110kg, I believe.

 

This is very helpful.

 

Cheers,

Tim

[lukepower]

Hi Tim,

 

alright, then trust me: The imbalance is there, somewhere It took me months of trial and error (and well, a defective USB hub in the mount) to get that sorted out. Those heavy tubes work quite well on the mount, but only if well balanced. I had to attach at some point a 2kg counterweigh just to balance the far end of the tube (as I have a newton focus with its focuser, too). But again, it might also be an USB issue, try to point at several different locations in the sky and then run the balance tool of Autoslew, that might help...