Runaway mount


Kent Kirkley
 

In a message dated 9/29/07 7:13:21 PM, peter@... writes:


(The focusser is controlled by the AP900)
Why is the focuser controller by the AP900???

Kent Kirkley


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Kent Kirkley
 

In a message dated 9/29/07 8:20:40 PM, peter@... writes:


It's a simple JMI focus motor plugged into the AP900, then controlled
via the mount and the ASCOM driver. It *should* work with focusMax.

Pete
So the JMI focus motor is just getting its power from the AP900.
That doesn't mean the mount is controlling the focus motor.
If there are power problems with the power to the mount then that might have
an influence on the power to the focus motor..

Kent Kirkley



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Peter Santangeli
 

For a few years my AP900 has shown an odd behaviour with slewing
manually with the keypad. Occasionally, when I release a direction
button, it doesn't stop, but just keeps on going.

I've been meaning to look into it, but frankly, I've just gotten used
to hitting the "stop" button at then end of each manual slew, and that
stops the runaway behaviour.

Last week though, I tried using FocusMax for the first time, and I saw
what seemed to be exactly the same behavior with the focusers. In the
middle of the focus max run, it would just take off in one direction
forever. (The focusser is controlled by the AP900).

Maybe they are unrelated... but it seems odd, and has reminded me again
that I should fix the run away slew problem.

Anyone have any ideas or similar experiences?

Pete


Peter Santangeli
 

It's a simple JMI focus motor plugged into the AP900, then controlled
via the mount and the ASCOM driver. It *should* work with focusMax.

Pete

--- In ap-gto@..., kgkirkley@... wrote:


In a message dated 9/29/07 7:13:21 PM, peter@... writes:


(The focusser is controlled by the AP900)
Why is the focuser controller by the AP900???

Kent Kirkley


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[Non-text portions of this message have been removed]


Peter Santangeli
 

Sorry, I guess I'm not being clear about the setup.

- The focusser is a JMI DXF3M with built in motor.
- The motor is plugged into the AP900.
- The focus commands are being generated by FocusMax, which is using
the ASCOM driver for the AP900
- The ASCOM driver is sending focus commands (I assume) to the AP900
- The AP900 is driving the focus motor

Pete

--- In ap-gto@..., kgkirkley@... wrote:


In a message dated 9/29/07 8:20:40 PM, peter@... writes:


It's a simple JMI focus motor plugged into the AP900, then
controlled
via the mount and the ASCOM driver. It *should* work with
focusMax.

Pete
So the JMI focus motor is just getting its power from the AP900.
That doesn't mean the mount is controlling the focus motor.
If there are power problems with the power to the mount then that
might have
an influence on the power to the focus motor..

Kent Kirkley



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[Non-text portions of this message have been removed]


John Winfield
 

Hi Pete,

I use pretty much exactly the same setup and have never had that
problem, although I use 100% PC control - I don't even have the
handset connected to the mount.

What versions of controller rom etc do you have? I use a CP2 with rev
D chip and as I say it works flawlessly, for both slewing and focus.
I seem to remember reading about manual slew runaway on the group here
in the past - did you try searching the archives?

John

--- In ap-gto@..., "Peter Santangeli" <peter@...> wrote:


Sorry, I guess I'm not being clear about the setup.

- The focusser is a JMI DXF3M with built in motor.
- The motor is plugged into the AP900.
- The focus commands are being generated by FocusMax, which is using
the ASCOM driver for the AP900
- The ASCOM driver is sending focus commands (I assume) to the AP900
- The AP900 is driving the focus motor

Pete

--- In ap-gto@..., kgkirkley@ wrote:


In a message dated 9/29/07 8:20:40 PM, peter@ writes:


It's a simple JMI focus motor plugged into the AP900, then
controlled
via the mount and the ASCOM driver. It *should* work with
focusMax.

Pete
So the JMI focus motor is just getting its power from the AP900.
That doesn't mean the mount is controlling the focus motor.
If there are power problems with the power to the mount then that
might have
an influence on the power to the focus motor..

Kent Kirkley



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[Non-text portions of this message have been removed]


Keith Graham <kag@...>
 

Hi Peter,

What slew speed are you using when the scope continues to run after you release the keypad button? When I slew at 600 or 900 using the keypad this does not happen. But if I slew at 1200, the mount does contunue to run for a few seconds after release of the button. I do not know why this happens, but I never slew using the keypad at 1200 anyhow as there really is no reason for me to do.

Keith Graham


Peter Santangeli
 

I never run above 600. I seem to remember it happens when I'm
centering, so anything 64x and up.

It's a scary/startling enough thing when it happens that I've never
let it run forever just to see what happens :-)

Pete

--- In ap-gto@..., "Keith Graham" <kag@...> wrote:

Hi Peter,

What slew speed are you using when the scope continues to run after
you release the keypad button? When I slew at 600 or 900 using the
keypad this does not happen. But if I slew at 1200, the mount does
contunue to run for a few seconds after release of the button. I do
not know why this happens, but I never slew using the keypad at 1200
anyhow as there really is no reason for me to do.

Keith Graham

[Non-text portions of this message have been removed]


Peter Santangeli
 

Thanks!

I just did an archive search, and found an interesting thread. It
seems that some people had issues with power cables that lead to
runaway slewing.

I *have* been having occasional power cable issues too, so maybe
that's the hint I need. I'll try the fix suggested (spreading the
halves of the inner prong in the supply cable).

Is the inner prong the ground? Is this actually a ground issue? If
so, might it also affect the focuser?

Maybe someone from AP has an idea.

Pete
--- In ap-gto@..., "John Winfield" <winfij@...> wrote:

Hi Pete,

I use pretty much exactly the same setup and have never had that
problem, although I use 100% PC control - I don't even have the
handset connected to the mount.

What versions of controller rom etc do you have? I use a CP2 with
rev
D chip and as I say it works flawlessly, for both slewing and focus.
I seem to remember reading about manual slew runaway on the group
here
in the past - did you try searching the archives?

John


--- In ap-gto@..., "Peter Santangeli" <peter@> wrote:


Sorry, I guess I'm not being clear about the setup.

- The focusser is a JMI DXF3M with built in motor.
- The motor is plugged into the AP900.
- The focus commands are being generated by FocusMax, which is
using
the ASCOM driver for the AP900
- The ASCOM driver is sending focus commands (I assume) to the
AP900
- The AP900 is driving the focus motor

Pete

--- In ap-gto@..., kgkirkley@ wrote:


In a message dated 9/29/07 8:20:40 PM, peter@ writes:


It's a simple JMI focus motor plugged into the AP900, then
controlled
via the mount and the ASCOM driver. It *should* work with
focusMax.

Pete
So the JMI focus motor is just getting its power from the AP900.
That doesn't mean the mount is controlling the focus motor.
If there are power problems with the power to the mount then
that
might have
an influence on the power to the focus motor..

Kent Kirkley



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[Non-text portions of this message have been removed]


Roland Christen
 

In a message dated 9/29/2007 7:13:30 PM Central Daylight Time,
peter@... writes:


For a few years my AP900 has shown an odd behaviour with slewing
manually with the keypad. Occasionally, when I release a direction
button, it doesn't stop, but just keeps on going.
The keypad works by sending software commands to the servo. If the command is
not received, then the action is not taken by the servo. It is possible that
there is a loose connection between keypad and servo. If you contact Howard or
Christine at AP, they can advise you on the steps to take to fix your
problem.

Rolando


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Roland Christen
 

In a message dated 9/30/2007 9:08:18 AM Central Daylight Time, kag@...
writes:


But if I slew at 1200, the mount does contunue to run for a few seconds
after release of the button.
In this case it indicates a lack of power to run the motors at the fastest
speed. What happens is the servo calculates a motor trajectory of 1200 times
sidereal, but if the motors cannot keep up because of a lack of power (or due to
excessive load), then the trajectory gets to its target position before the
motors do. Thus the motors continue to run until they catch up to the commanded
position, even if you let go of the button. This is entirely different
situation than the one where the motors continue to run forever (possibly due to a
bad connection or a faulty UART).

It is good for you all to understand some of these problem modes so that you
do not spend a lot of time and effort going down blind alleys trying to fix
things the wrong way. There is always a logical reason why things occur the way
they do. Most of it is written up in the manual (can be seen on our web site)
so please check there first if you have any strange symptoms.

Rolando


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Dean Salman <cluster@...>
 

Hi Group,

I had this same problem. My issue was using just the KeyPad could
cause a runway. I had another issue with hooking a 2nd serial cable
and using PulseGuide and the Sky connected at the same time.

My first repair was to replace the D chip with the E chip. Guess
what, I never could reproduce the keypad run away again. For only
$45 and an excellent document on replacing it, it was well worth it.

The UArk chip in my mount was defective and I guess only the 2nd
cable connected would see the problem. Replacing that was just as
easy. I did get the Max chip as well in case that was the next
step, but the one screw had stripped head so I can't remove that
chip. But I guess it was not needed because everything works great
now.

Dean


--- In ap-gto@..., chris1011@... wrote:

In a message dated 9/29/2007 7:13:30 PM Central Daylight Time,
peter@... writes:


For a few years my AP900 has shown an odd behaviour with slewing
manually with the keypad. Occasionally, when I release a
direction
button, it doesn't stop, but just keeps on going.
The keypad works by sending software commands to the servo. If the
command is
not received, then the action is not taken by the servo. It is
possible that
there is a loose connection between keypad and servo. If you
contact Howard or
Christine at AP, they can advise you on the steps to take to fix
your
problem.

Rolando


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[Non-text portions of this message have been removed]