GeorgeCarey

I am not sure how that would be done. I don't fancy taking anything apart.

Yes, I would only try 5.5A to start with. This is the graph from yesterday:

I am waiting to hear from ASA. The only option I haven't tried is to power the mount with a12V battery. I charged a big car battery up but the voltage was only 10V so I did not use it. However, I am almost certain that it is not a power supply problem. The voltage in DEC rises in the same way every time, and is slow and steady. Voltage spikes would tend to produce random errors. Yesterday I did a trial and got a similar effect in the RA Axis, which is quite rare. It is almost as if the error occurs when the total current hits 5A (limit set in the ini file), and then whichever current is highest runs away to 5A. I will post yesterday's graph later. I might try altering the 5A limit set in the ini file and see what happens.

Superb image, especially with an 18.5 sky!

New power supply, capable of 30A. Very low ripple and noise, The problem remains.

Hi Robert, You need ASA to make you a 'beta tester' . The beta board will then become visible. George

From what I can gather the 'Set New Home Position' command is an ultimate 'Sync'. When you make a pointing model you start by syncing on a star. After the pointing model if you move to a new star it will probably be a bit off because the pointing model is doing all sorts of magic. If you then centre that star and 'Sync' everything will be fine, but if you shut down then Autoslew will forget the Sync position. So, after your first accurate Sync on a star, go to 'Set New Home Position' and Autoslew will then remember where it is pointing when you next switch on. That seems to work for me. I did my last new home position in September 2014 and have not had to Sync since.

Doesn't that rather imply that if you bolt the DDM85 to the pier and then do a polar alignment, then the pier will have put itself into the correct position? George

That would work if you were certain that the optical axis of the telescope was exactly parallel to the telescope plate on the DEC axis. Also a very good polar alignment. But if you are adjusting the pier, what will that do to the polar alignment?

The power supply easily gives 9+ amps.

Hi Nigel, You have to tell Autoslew to log the data. I think it is in 'Drive.... Settings'.

My existing power supply is a MeanWell. I would be surprised if it is really the problem. I have sent another email to ASA for help. http://www.meanwelldirect.co.uk/product/150W-12V-12-5A-High-Reliability-Miniature-Enclosed-Switching-Power-Supply/RS-150-12/default.htm

What about this as an alternative power supply? http://www.maplin.co.uk/p/375w-linear-dc-variable-voltage-bench-power-supply-rp10l

I set the mount tracking. No calibration loaded so the DEC axis has absolutely nothing to do. The error occured again at total current 5A. I note that in the update report there is this... Version 5.0.5.3 - problem that RA motor not powered on with Hall Sensors installed after start removed - all user data now stored at application data folder (instead of program files folder please read extra document about where Autoslew now saves which data depending on Windows Version - removed BUG of Version 5.0.5.2 with DDM85 mounts where Polar Alignment was again inverted (DDM60 mounts where not affected) - removed Bug where location (if read from GPS) was wrong in sign if Longitude was Westerly. Version 5.0.5.4 - In Misc Settings you can now find a checkbox "Try to automatic Clear errors". This can be used in robotic telescopes where you want to prevent any user interaction. Keep in mind though, that all error messages have a reason that needs some solvage. - Programmed a procedure to prevent over current stuck and position errors This does not seem to be working.

What is very odd is that the logfile now says that the total current is 4.2A but the meter on the power supply says 2.5A.

Slow rise in DEC current continues. From 0.3A to 2.2A in 76 minutes. Will the total current get to 5A?

Hello Adamo, My voltage was 11.8V. There is a small adjuster in the power supply and I have increased the voltage to 12.7V. It may be too soon to be sure but the DEC current at the moment is almost steady, only a very small rise. George

Waldemar, the total 5A theory seems to be valid. These lines are in the log file: Current Limit (A)=5 Current Peak Limit (A)=10 Current Peak Time (s)=3 Perhaps this means that if the current stays at 5A or above for three seconds then something is triggered?

The power supply is rated at 10A, but I will do some checks to confirm it. I might also hook up an oscilloscope and see if the output is noisy. I have never considered the RA current + DEC current total. I have hundreds of these graphs and will take a look. The high current in my mount does seem an issue. Most people seem to have a total nearer 1A, and that is what the DDM60 is claimed to run at. No response from ASA yet, but it has been Easter...

I have changed the USB lead and done a fresh install on a new PC. Unfortunately the error persists. The DEC motor current dropped to zero (I thought maybe the problem was cured), and then did its usual trick of rising to slowly 3A and then rapidly to 5A. At this point you cannot slew the mount. Next option is to try a different power supply...

I put Nigels equations in a spread sheet. These are the values around 6.62: 22.16 6.696 22.15 6.691 22.14 6.687 22.13 6.682 22.12 6.678 22.11 6.674 22.10 6.669 22.09 6.665 22.08 6.660 22.07 6.656 22.06 6.652 22.05 6.647 22.04 6.643 22.03 6.638 22.02 6.634 22.01 6.629 22.00 6.625 21.99 6.620 21.98 6.616 21.97 6.611 21.96 6.607 21.95 6.602 21.94 6.597 21.93 6.593 21.92 6.588 21.91 6.584 21.90 6.579 21.89 6.574 21.88 6.570 21.87 6.565 21.86 6.560

I will try that. I found another strange thing... I set Autoslew to save its logfile. It seems to handle RA and DEC differently. See the lines in blue: 15:55:18.910: Loaded Ini-File C:\ProgramData\ASA\Autoslew\Autoslew.ini 15:55:18.910: Config not found 15:55:18.910: Pointing-Configuration C:\ProgramData\ASA\Autoslew\39starsSept21_2014.cfg loaded 15:55:18.910: Ini File: C:\ProgramData\ASA\Autoslew\Autoslew.ini 15:55:19.112: Found the following FTDI Decives: 15:55:19.112: ASA Elektronik 15:55:19.128: FT232R USB UART 15:55:19.128: 15:55:19.128: QSI 600 Series Camera B 15:55:19.128: 15:55:20.407: CLServo Vers.5.2.0.5: 2 axis init OK 15:55:21.718: To long sleep of main timer, was reset by controltimer 15:55:21.718: AliveProgresscount stopped at 0 15:55:22.154: Welcome Autoslew Vers 5.2.1.2 15:55:45.196: To long sleep of main timer, was reset by controltimer 15:55:45.196: AliveProgresscount stopped at 100 15:56:03.385: Starting homefind 15:56:18.252: RA/AZ calibrated OK ! 15:56:33.587: DE/AL calibrated OK ! 15:56:33.603: To long sleep of main timer, was reset by controltimer 15:56:33.603: AliveProgresscount stopped at 999 15:58:12.476: Interface setting TargetRightAscension to 5.30 False 15:58:12.476: Interface setting TargetDeclination to 46.01 True 15:58:12.476: Interface SlewToTargetAsynch 15:58:12.476: Starting Slew to RA 05.30h DE 46.01d EPOCH 0000 15:59:48.478: Interface setting TargetRightAscension to 5.93 False 15:59:48.478: Interface setting TargetDeclination to 7.40 True 15:59:48.478: Interface SlewToTargetAsynch 15:59:48.478: Starting Slew to RA 05.93h DE 07.40d EPOCH 0000 True for DEC and False for RA

I have always thought that the DEC axis moves more easily in one direction than the other. The balance tool seems to confirm this. The movement of the yellow and red bars is not the same for both directions. The top bars seem to struggle to reach maximum. Does your mount show this? See this video https://www.youtube.com/watch?v=SlVCVl9lCPk

A used a different USB lead... problem remains.

Thanks for those equations. I worked through and got 20.11 is NELM 5.57, as you said. An SQM of 22.05 I can only dream of being 12 miles from Birmingham, UK. George