Re: [M]: lx200:12Vconv andPictor
| Subject: | Re: [M]: lx200:12Vconv andPictor |
| From: | R. A. Greiner |
| Date: | Sun Jun 15 06:44:39 1997 |
John Hoot wrote:
>
> > >> Summary on theMeade DC-DC converter, all Meade LX-200 scopes will run
> >on
> > >> 12VDC - 18VDC. The processor board only sees 12VDC because of a
> >on-board
> > >> regulator. The motors run stronger at 18VDC, thus Meade made the
> >change.
> > >> The motors are rated to 24VDC so no problem there. Focusers such as the
> > >> JMI zero image unit runs at one speed when the LX-200 is powered by
> > >> 18VDC, and two speeds at 12VDC.
I believe this statement is not correct. I have JMI focussers on two
LX200s.
Both JMIs work perfectly at both slow and fast speeds using the LX200
control
panel socket and the key pad buttons. Of course I run my LX200 at the
correct
voltage as recommended by Meade.
> >
> >A side note which may be of interest to other Pictor-series owners, I
> >discovered last night (after reading R. Greiners msg) that the Pictor
> >autofocus routine will not work at less than 18 v., not even at 15 V. which
> >is what I have been operating at these past few days. The "fine" focus
> >motor drive setting is almost inoperative at this voltage.
This observation is in exact agreement with mine. The focusser will
only operate
correctly and reliably with the correct LX 200 voltage.
There is a very good reason for this. It has to do with the
voltage/current and
tork/speed characteristics of DC motors which is fundamental to their
design.
(I hope this does not break my promise to not mention the actual
voltages in question!)
Doc G
>
> > >> Summary on theMeade DC-DC converter, all Meade LX-200 scopes will run
> >on
> > >> 12VDC - 18VDC. The processor board only sees 12VDC because of a
> >on-board
> > >> regulator. The motors run stronger at 18VDC, thus Meade made the
> >change.
> > >> The motors are rated to 24VDC so no problem there. Focusers such as the
> > >> JMI zero image unit runs at one speed when the LX-200 is powered by
> > >> 18VDC, and two speeds at 12VDC.
I believe this statement is not correct. I have JMI focussers on two
LX200s.
Both JMIs work perfectly at both slow and fast speeds using the LX200
control
panel socket and the key pad buttons. Of course I run my LX200 at the
correct
voltage as recommended by Meade.
> >
> >A side note which may be of interest to other Pictor-series owners, I
> >discovered last night (after reading R. Greiners msg) that the Pictor
> >autofocus routine will not work at less than 18 v., not even at 15 V. which
> >is what I have been operating at these past few days. The "fine" focus
> >motor drive setting is almost inoperative at this voltage.
This observation is in exact agreement with mine. The focusser will
only operate
correctly and reliably with the correct LX 200 voltage.
There is a very good reason for this. It has to do with the
voltage/current and
tork/speed characteristics of DC motors which is fundamental to their
design.
(I hope this does not break my promise to not mention the actual
voltages in question!)
Doc G
