EFT
Vendor - Deep Space Products
Reged: 05/07/07
Loc: Phoenix, AZ
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Re: LX-800
[Re: n2dpsky]
#5204521 - 05/03/12 08:06 PM
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Of course. The instrument needs to be balanced. However, if the motors have lots of torque, it will be less sensitive to minor variances. I guess we're only debating about how keenly it must be balanced to prevent damage to the motors. In my experience, I have found it's not nearly as critical as some suggest. Only the engineers at Meade know what its design capacity is. If they told me if wasn't critical, I probably accept that. Obviously, the proof is in the pudding. Once this bugger has been sorted, we need to see some photos.
Realistically, it is fairly difficult to damage servo motors themselves as well as the gears usually used in mounts. Extra wear is possible but it is a very slow process in machinery that moves this slow. However, the weak link can be the motor gearboxes depending on what type of gears are used in there. Nylon gears, often used to make gear boxes smoother and quieter, are much more easily damaged than metal gears.
Most mounts benefit from being well balanced. It is not that they will not work if they are not well balanced, but that they will usually not work as well. Poor balance is just one more thing that tends to bring out the defects in mount design and manufacturing. In order to address the inability to properly balance, one company brought out a new mount version that supplies more power to the motors to overcome the poor balance while another company released a new version of their mounts with a different clutch system and added software to try to determine the balance of the mount. Neather is a particularly good substitute for being able to properly balance a mount in the first place, but the software idea might be the best work around (rather than redesigning the hardware). However, some mount designs simply do not lend themselves to being able to allow the axes to turn freely in order to achieve balance and thus the need for work arounds to the problem. Hopefully, this is not a big issue for the new mounts or it is likely that we will see a quick redesign of the clutch system if it actually is the cause of the problem. Right now there are not enough samples to judge by.
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Enzino
journeyman
Reged: 01/12/07
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Motor current absorbtion
[Re: n2dpsky]
#5204602 - 05/03/12 09:13 PM
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I wonder if they could have the handheld controller to show the current taken by th RA motor when slewing in both directions. When the current is the same it should be balanced... It shold be possible to even connect an ampere meter in series to the power lead and look at the current slewing at max speed in both directions. Maybe?
V.
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Gord
Carpal Tunnel
Reged: 01/06/04
Loc: Toronto, ON, Canada
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Re: Motor current absorbtion
[Re: Enzino]
#5204637 - 05/03/12 09:59 PM
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If I recall, there was something like this on the old LX200 classics (the current draw level), or at least that's what I understood it to be.
If the mount is properly balanced with good bearings, there is actually very little work for the motors to do regardless of the load. The most work is done getting things going and slowing them down, and this is usually taken care of with programming the "ramps" the speed up or down. I've seen the difference an easy vs. hard to balance mount makes, and the easy balance one just seems to work better.
Clear skies,
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: Enzino]
#5204649 - 05/03/12 10:08 PM
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I wonder if they could have the handheld controller to show the current taken by th RA motor when slewing in both directions. When the current is the same it should be balanced... It shold be possible to even connect an ampere meter in series to the power lead and look at the current slewing at max speed in both directions. Maybe?
V.
I like this idea. Wonder if there is a way to work this out without voiding my warranty. I've already made a list of changes I am going to make when my warranty expires.
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Enzino
journeyman
Reged: 01/12/07
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5204668 - 05/03/12 10:20 PM
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There should be no warranty implication... just use a bench power supply to power the mount. It will give you real time amperage.
V.
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JSnuff1
sage
Reged: 12/29/04
Loc: NY
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5204676 - 05/03/12 10:25 PM
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I wonder if they could have the handheld controller to show the current taken by th RA motor when slewing in both directions. When the current is the same it should be balanced... It shold be possible to even connect an ampere meter in series to the power lead and look at the current slewing at max speed in both directions. Maybe?
V.
I like this idea. Wonder if there is a way to work this out without voiding my warranty. I've already made a list of changes I am going to make when my warranty expires.
All you would have to do is replace the stock cable, if I recall correctly its a pretty standard cable that runs from the gearbox to the controller, so just make one and stick an analog ampere meter in series.
That would actually be a neat little mod to test balance.
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JimMo
I'd Rather Do It Myself
Reged: 01/08/07
Loc: Under the SE Michigan lightdom...
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Re: LX-800
[Re: Whichwayisnorth]
#5204693 - 05/03/12 10:37 PM
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Darn moon this weekend is going to be insane.
Yes, but it's the best time to try out new mounts. Nothing worse than trying out a new mount on a great Moonless night and wasting the night trouble shooting.
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budman1961
scholastic sledgehammer
Reged: 02/25/11
Loc: Springfield, MO
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Re: Motor current absorbtion
[Re: Gord]
#5204809 - 05/03/12 11:51 PM
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If I recall, there was something like this on the old LX200 classics (the current draw level), or at least that's what I understood it to be.
If the mount is properly balanced with good bearings, there is actually very little work for the motors to do regardless of the load. The most work is done getting things going and slowing them down, and this is usually taken care of with programming the "ramps" the speed up or down. I've seen the difference an easy vs. hard to balance mount makes, and the easy balance one just seems to work better.
Clear skies,
You are correct, and its pretty useful. It is a red linear scale, that shows draw. The handbox has a balance function, when it is turned on, the scope goes up and down, and you eyeball the scale to see if the motors are working harder in 1 direction, or the other....
Andy
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EFT
Vendor - Deep Space Products
Reged: 05/07/07
Loc: Phoenix, AZ
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Re: Motor current absorbtion
[Re: Enzino]
#5204838 - 05/04/12 12:23 AM
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I wonder if they could have the handheld controller to show the current taken by th RA motor when slewing in both directions. When the current is the same it should be balanced... It shold be possible to even connect an ampere meter in series to the power lead and look at the current slewing at max speed in both directions. Maybe?
V.
The problem is that a system like that assumes that any stiction that is causing the stiffness is equal in both directions. In theory it should be, in practice it rarely is. In addition, by having to slew the mount you are also introducing the gears (and their associated random and periodic error) into the equation. Again, it shouldn't matter but it does. Thus you still may not be balanced even if the reading appears to be equal in both directions. In very well designed and constructed systems this is likely not a problem but in mass-produced system problems are far more likely.
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: EFT]
#5206620 - 05/05/12 12:56 AM
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Here I am at a quarter to 10pm with clear skies and no wind. If there wasn't a full freakin moon it would be perfect! Well there are still stars out there and it was time to get back out there and get this whole thing figured out.
Starlock STILL doesn't track anything.
First things first. Hooked up the cable to the back of the RS232 port on starlock so I could use the utility to see what it sees. Both the widefield and narrow field cameras seemed like they were in focus. Nice clean clear stars. So far so good.
Noticed that when you have the cable plugged into the back of the RS232 port the starlock is disabled in the mount control So I had to unplug it and reset the mount.
Did the one star alignment so the OTA was aligned with starlock. I tried to slew to a few objects and it did NOT center. What I ended up doing is cycled the mounts power and did an easy alignment and it did the auto-centering using the widefield camera. I will say it NAILED it by putting the star dead center in the crosshairs. Working great! But once again by the time you count to 10 the star runs off into the weeds. Starlock is blinking indicating it is looking for a star to lock on. PLENTY of stars for it to lock on. I could see about 20 with the naked eye around my target. I am hoping Gary has better luck this weekend than I do. I am going to call Meade again tomorrow.
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sphelps
member
Reged: 07/03/10
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5206637 - 05/05/12 01:19 AM
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Here I am at a quarter to 10pm with clear skies and no wind. If there wasn't a full freakin moon it would be perfect! Well there are still stars out there and it was time to get back out there and get this whole thing figured out.
Starlock STILL doesn't track anything.
First things first. Hooked up the cable to the back of the RS232 port on starlock so I could use the utility to see what it sees. Both the widefield and narrow field cameras seemed like they were in focus. Nice clean clear stars. So far so good.
Noticed that when you have the cable plugged into the back of the RS232 port the starlock is disabled in the mount control So I had to unplug it and reset the mount.
Did the one star alignment so the OTA was aligned with starlock. I tried to slew to a few objects and it did NOT center. What I ended up doing is cycled the mounts power and did an easy alignment and it did the auto-centering using the widefield camera. I will say it NAILED it by putting the star dead center in the crosshairs. Working great! But once again by the time you count to 10 the star runs off into the weeds. Starlock is blinking indicating it is looking for a star to lock on. PLENTY of stars for it to lock on. I could see about 20 with the naked eye around my target. I am hoping Gary has better luck this weekend than I do. I am going to call Meade again tomorrow.
Thanks for the update.
I'm assuming you repositioned the the starlock cameras to the factory position so it would know which way is left, right, etc. to move the mount. I know you rotated them at one point.
Thanks again and hope you have better luck with Meade. I would have them just overnight you a replacement mount asap so you can put this behind you.
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mmalik
Carpal Tunnel
Reged: 01/13/12
Loc: USA
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5206650 - 05/05/12 01:31 AM
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PLENTY of stars for it to lock on.
Moon is not, and shouldn't be a contraindication for auto guiding. As you said, there are stars to lock on; and there would be lot of stars better than 11th magnitude to lock on even with the moon lit sky. Something doesn't seem right here.
Let's look at the big picture here; is there anyone out there who may have successfully tested LX800? Gary and yourself shouldn't be the only ones I presume who have this mount in their hands? Given the stakes, there should be a hotline you could call into anytime of the night where they could walk you through while you are under the stars getting this thing figured out. Day time calls are much detached from the real action. Suggest that to Mr. VP next time you call. Good luck to you!
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sphelps
member
Reged: 07/03/10
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Re: Motor current absorbtion
[Re: mmalik]
#5206672 - 05/05/12 02:06 AM
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PLENTY of stars for it to lock on.
Moon is not, and shouldn't be a contraindication for auto guiding. As you said, there are stars to lock on; and there would be lot of stars better than 11th magnitude to lock on even with the moon lit sky. Something doesn't seem right here.
Let's look at the big picture here; is there anyone out there who may have successfully tested LX800? Gary and yourself shouldn't be the only ones I presume who have this mount in their hands? Given the stakes, there should be a hotline you could call into anytime of the night where they could walk you through while you are under the stars getting this thing figured out. Day time calls are much detached from the real action. Suggest that to Mr. VP next time you call. Good luck to you!
I would like to know the same thing. I haven't heard of any success stories as of yet although the weather hasn't really been the best lately.
They should offer tech support after hours.
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: mmalik]
#5206675 - 05/05/12 02:10 AM
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Yes I put the starlock mount back into the original position. The issue is starlock is not locking on anything. The red led flashes when it is looking for something and is steady when it locks. I don't think I've ever seen it steady.  It simply doesn't lock. You can probably guess I have another video coming. This one over 20 minutes showing the entire process. Hoping it is just me doing something stupid and overlooking something but I can't see what it could be.
As I mentioned in a previous post that Chris Morrison said he would consider coming out to my house to meet with me and get this thing licked. I was hoping I could get it resolved tonight and not need to call in that favor but I spent a lot of money on this mount specifically because it is supposed to actually LOCK on a star and guide not just blink a light at me. I'll post a link to the video asap.
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blueman
Vendor Blue Sky Accessories
Reged: 07/20/07
Loc: California
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5206690 - 05/05/12 02:41 AM
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Man, this is a tough situation, you are kind of on your own. You are getting support from Meade, but geez, you would think something would go right. 
Hope you have a bit of luck soon.
Blueman
Quote:
Yes I put the starlock mount back into the original position. The issue is starlock is not locking on anything. The red led flashes when it is looking for something and is steady when it locks. I don't think I've ever seen it steady. It simply doesn't lock. You can probably guess I have another video coming. This one over 20 minutes showing the entire process. Hoping it is just me doing something stupid and overlooking something but I can't see what it could be.
As I mentioned in a previous post that Chris Morrison said he would consider coming out to my house to meet with me and get this thing licked. I was hoping I could get it resolved tonight and not need to call in that favor but I spent a lot of money on this mount specifically because it is supposed to actually LOCK on a star and guide not just blink a light at me. I'll post a link to the video asap.
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: blueman]
#5206697 - 05/05/12 02:57 AM
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I used the Starlock utility to confirm the stars were in focus but maybe they just looked like it and the narrow field camera is not really in focus. I could clearly see two stars. One was Arcturus which was bright and there was smaller pinpoint stars I could make out. seems to me they wouldn't be pinpoints if it was out of focus so bad it couldn't lock.
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Gord
Carpal Tunnel
Reged: 01/06/04
Loc: Toronto, ON, Canada
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5206818 - 05/05/12 07:41 AM
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The 11th mag thing strikes me as a problem with this whole idea. What I mean is that while there would most likely be a star at least that bright in a wide-ish field, what if there is not? Does that mean the thing will not work at all?
The other part is that I expect it's a gradual thing. It won't work perfectly if there is an 11th mag star, but not if it's 11.1. What I expect is that this is getting to the limit as to where it's just not going to work at all. I expect there would be a range of stars of brightness brighter than 11th mag where the locking success is kind of marginal until you get down to a point where it's no problem.
And of course this will all likely be affected by conditions as well (the sky brightness, humidity, temp, seeing, trans, etc.). There are enough caveat's like this with a normal guider that make me think this could be fairly limited in terms of capability and effectiveness.
Clear skies,
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David Pavlich
Transmographied
Reged: 05/18/05
Loc: Mandeville, LA USA
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Re: Motor current absorbtion
[Re: Gord]
#5206925 - 05/05/12 09:32 AM
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Question: If you disable Starlock and treat it like a typical GEM/OTA, does the mount automatically go into Sidereal tracking? If not, perhaps the problem isn't Starlock, maybe the mount isn't tracking. If you're counting to 10 and the star is out of the FOV, unless you have a really poor polar alignment, the star should hang around for a while if the mount is tracking.
Or does the mount not track until it has locked onto a star?
David
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: David Pavlich]
#5207035 - 05/05/12 11:20 AM
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With Starlock disabled it tracks just fine. When starlock is enabled it basically tracks for only a few seconds then stops as if it was expecting starlock to take over and guide and it doesn't. I don't really understand the process myself. My understanding is the mount should track as normal and the starlock would auto correct tracking errors.
Starlock enabled: Doesn't track, doesn't guide.
Starlock disabled: Tracks but doesn't guide.
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Whichwayisnorth
professor emeritus
Reged: 07/04/11
Loc: Southern California
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Re: Motor current absorbtion
[Re: Whichwayisnorth]
#5207037 - 05/05/12 11:21 AM
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Here is my recent video. I cut quite a bit out to save time and space but everything is there.
http://youtu.be/kErOduqqqLI
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