Mesu 200 - Sitech II, lost all the Servo config data all of a sudden


Sedat Bilgebay
 

Dear group,

This is a 5 year old Mesu 200. I have no clue as to what caused this hiccup but it's happening to me for the first time.  As usual, the other day, I was preparing for the night and when I pushed the East button on the Sitech.exe the mount started slewing to west  at full speed. So I stopped playing with the buttons and started Servo Config to check the parameters... My settings can be seen in the first image below but what I found were the values in the second screenshot:





I reloaded the orijinal .car file to the controller then edited  a few of them with the values in the top image. I am using the mount at slow speeds and with much less acceleration than originally configured by Lucas.

Now the mount is back to normal and running perfectly. 

Has any of you experienced a similar situation ? What could be the reason behind this. As I said, this is happening to me first time in 5 years of operation. This seemed to me like the AP mounts' internal battery failure where the mounts is not able to hold the user adjusted parameters and reverts to a default configuration. I know Sitech stores this info in a NV memory but then how on earth this hiccup occurred ?

Thank you for reading and sharing your experiences/comments with me.

Clear skies

Sedat Bilgebay


CandCShaw
 

Sorry for your problem!   Sitechexe will create a “new” Sitech.CFL file if it cannot find one. Sounds like the previous Sitech.cfg may have gotten corrupted?   Do you do backups on your PC?

Chuck


On Jun 6, 2021, at 9:33 AM, Sedat Bilgebay <bilgebay@...> wrote:

Dear group,

This is a 5 year old Mesu 200. I have no clue as to what caused this hiccup but it's happening to me for the first time.  As usual, the other day, I was preparing for the night and when I pushed the East button on the Sitech.exe the mount started slewing to west  at full speed. So I stopped playing with the buttons and started Servo Config to check the parameters... My settings can be seen in the first image below but what I found were the values in the second screenshot:

<Servoconfig_SB_before.jpeg>


<Servoconfig_SB_after.png>


I reloaded the orijinal .car file to the controller then edited  a few of them with the values in the top image. I am using the mount at slow speeds and with much less acceleration than originally configured by Lucas.

Now the mount is back to normal and running perfectly. 

Has any of you experienced a similar situation ? What could be the reason behind this. As I said, this is happening to me first time in 5 years of operation. This seemed to me like the AP mounts' internal battery failure where the mounts is not able to hold the user adjusted parameters and reverts to a default configuration. I know Sitech stores this info in a NV memory but then how on earth this hiccup occurred ?

Thank you for reading and sharing your experiences/comments with me.

Clear skies

Sedat Bilgebay


Sedat Bilgebay
 

Thank you Chuck.

My Sitech.cfg is in good shape, no problem with that.

The problem is with the mount specific parameters stored in Sitech II. All the settings that Lucas Mesu keyed in like the tick numbers, motor gain parameters etc were erased. As soon as I uploaded the the configuration from the *.car file he sent to me everything got back to normal. All I want to know os why this has happened and if it can be avoided. I have been using the mount in the same way for the last 5 this never happened before.


CandCShaw
 

Great that it is working!  Download the .car File and make a backup copy. Do the same with the .cfg file for Sitechexe.  

Did you have any electrical disturbances (spikes, lighting, surges, etc) after the last time it was working ok?  When was the last time you flashed the controller eprom?

Cheers!

Chuck


On Jun 6, 2021, at 2:06 PM, Sedat Bilgebay <bilgebay@...> wrote:

Thank you Chuck.

My Sitech.cfg is in good shape, no problem with that.

The problem is with the mount specific parameters stored in Sitech II. All the settings that Lucas Mesu keyed in like the tick numbers, motor gain parameters etc were erased. As soon as I uploaded the the configuration from the *.car file he sent to me everything got back to normal. All I want to know os why this has happened and if it can be avoided. I have been using the mount in the same way for the last 5 this never happened before.


Sedat Bilgebay
 

Hello Chuck,

I have the back ups for both the .car and .cfg files. There were no electrical disturbances or power cut off at this time and the weather is beautiful these days. This is really mysterious. The only thing I can think of is this: I'm using the mount remotely via Splashtop through my Mac, ipad or iphone. When I use my ios devices, I need to press the direction buttons 3 times in quick succession and sometimes I press 4-5 times :) Maybe this triggers a "reset" function in the controller. This is exactly what happened prior to the problem, I pressed the screen 4-5 times accidentally then I ran into the problem.

Last time I flashed the eeprom was in 2015 when the mount was brand new and Sitach DEC led started blinking for some unknown reason. At that time Dan had kindly sent V93.bin together with the some instructions and since then I had no problem related to Sitech. It just runs perfectly.

Last night all went well... we will see.


paul K
 

Hi Sedat, in your original post you mentoned
'I am using the mount at slow speeds and with much less acceleration than originally configured by Lucas.'

I was wondering why you do that? I have the same mount and it's roughly the same age. My dec motor shaft snapped recently and I am in process of reinstalling it wth Lucas now it's been repaired.

I think I may have moved the dec axis too quickly by hand when powered down and perhaps that caused the shaft to break, but I'm not really sure if that was the cause as I'd done it many times before. Lucas Mesu has been really helpful with it.

best wishes
Paul


Don W
 

Hi Paul,
The greatest load on the servo and drive components generally is the acceleration and deceleration loads.  SiTech ServoConfig.exe allows you to set the rates.  A slower acceleration setting really is not noticeable as far as timing a slew, but it can reduce the loads which "Might" have caused your failure.  This is conjecture on my part.

Depending on the load (the telescope and equipment and the required balance weights) the highly loaded friction drive pins are relatively small cross section and operate under a lot of stress.

Don W


Sedat Bilgebay
 

Hello Paul, lowering the acceleration is helping a lot with avoiding the slip in the drive system which in turn allows for more accurate slews and quicker centering with much greater accuracy. My system is able to center with 1 pixel accuracy at even 0.3" plate scale. 

Meanwhile, my RA shaft got loose in 2019 but was still driving the rest of the discs thanks to the tension  against the drive disc and the friction this created. iI was hard to realize this since guiding was correcting the errors mostly. The only issue was the tracking speed needed to be adjusted depending on where the scope was pointing at. Long story short, I dismantled the motor and saw that the drive pin was very very loose :) I asked Lucas to sell me a new motor but he insisted that I should return the motor to Holland. Sending anything for repairs and receiving it back from abroad is a very costly and complicated procedure in Turkey. So I had to repair the motor my self. The mount is running perfectly since then and even better than it's original condition. I guess the original drive pin had some runout because when rotated the the RA axis I was able to hear a non uniform, knocking sound.. now the sound is very uniform at every position and my guiding also shows that. In good seeing I'm able to go as kow as 0.3" RMS. Even had 0.26" for a couple hours when my seeing allowed.

By the way, I glued the drive pin to the motor coupling with the help of a centering jig I manufactured for this purpose. The stuff I used for gluing is Chemlock's Lock 38. Did and incredible job. Press fitting etc would be too risky for me without knowing the specifics of the motor and the encoder assy. 


paul K
 

Thanks for sharing this Sedat, very useful to know about the acceleration and accuracy. Shame about the complexity of shipping for repair. I just shipped my motor to Holland and Lucas has repaired and returned it. So called BREXIT has made it more difficult to ship to and from the U.K. too.
Paul