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heres my scanner displaying the ilda test pattern.
im using the fb3, angle of 50% scan rate of 90%
im guessing they need tuning??
http://i80.photobucket.com/albums/j1...9112007002.jpg
http://i80.photobucket.com/albums/j1...9112007001.jpg
http://i80.photobucket.com/albums/j1...s/19112007.jpg
Yes they need tuning but the angle is not 50% - 50% is a percentage not an angle. what were you up to in maths class ? What was her name and have you got pictures?
The angle can be worked out by measuring the width of the scan and the distance between the scanners and the screen. You could get your calculator out and dust off your brain to work it out or.....
...go to Pangos page about scan angles - here
http://www.pangolin.com/userhelp/scanangles.htm
Rob
PS on Pango what does scan rate of 90% equate to????
R
yeah i know its not the angle, im just a bit lazy to work out the angle :(
but i will before the next meet.
so now the question is, does anyone know what i need to to do tune my scanners. i have original dt40's
http://i80.photobucket.com/albums/j1...07331Large.jpg
twiddle some pots :)
Sorry I dont know which ones do what - maybe Jian can shead a little light?
Rob
ummm may pm him.
which pots do i need to twist? is it the gain ones???
Im sure there will be a proceedure that will get you the best result and this will involve doing things in a certain order. One thing is clear you have overshoot in the Y axis which with something like medialas microamps will adjust with Low frequency damping. but dont know how that relates to dragon tiger amps
Rob
It looks all out of whack. Gain is not right so one side is larger than the other. You also have overshoot. Definitely needs tuning. Do you know which pot is which? That's step 1.
Hi Andy,
That problem probably be from "overdriver".
So the scanner is dead.You can't tune it to work perfection.
Now you may :
1.That scanner use for beam show only,no any prblem,you almost can't find where different.just show for animation very bad.
2.Send to me repair.
3.upgrade to DT40pro.
Jian
I'm working on a scanner tutorial that might help, but it won't be ready for some time yet. :(
One thing: remember that most scanners can't display the test pattern at full size (unless you're using the modified pattern that has the very large outer square and then the minature version of the full pattern inside that large square). The standard ILDA test pattern *will* look like crap if you try to display it at too wide a scan angle. (It overdrives the scanners, which can lead to vibration/resonance issues.)
When tuning, I usually start with the size (or gain) set at around 5 % and then slowly increase it. When you get to the point where the circle in the middle of the pattern stops getting larger, STOP. Back your size off by 1 increment and tune them right there. Depending on the scanners you have you'll probably be at something like 10-15% of full scale, which should correspond to an optical scan angle of between 8 and 20 degrees. (Again, depending on the brand of scanner you have; you need to measure it to be certain.)
Also, don't start twiddling pots unless you know what you are doing. You can kill your scanners if you let them get away from you.
Adam
I'm not sure how similar the DT-40's are to the DT-40 Pro's but in this thread:
http://www.photonlexicon.com/forums/...ead.php?t=2266
about 3/4 the way down there is a post from yaddatrance he attached a PDF file which shows what to adjust and what it affects. It seems very helpful (I personally own DT-40 Pro's and have yet to actually tune them using his methods, but it seems like it might be of a lot of help).
-Max
Quote:
Originally Posted by jian725
dead you must be joking!!!! ive hardly used them
they display animations just fine you cant notice any problems.
how do for tem to be repaired if they are faulty???
im not turning any pots until i know whats what.
jian do you have any data on what pot does what??
took me a while to find but bingo
http://www.photonlexicon.com/forums/...highlight=dt40
what do i need to turn to start tuning?
ok at a distance of 3 metres, the width is 1m and height is 1.35m
so 15% = 8 degrees
OK, I finally got home where I could look at the picture you posted. Your "Y" scanner amp needs to be tweaked for sure. While I can't really walk you through a complete tuning right now, I might be able to help you get it good enough that you can live with it until I finish the scanner tuning tutorial sometime after Thanksgiving. Try this first:
With the size set to 15%, load the test pattern. Now, in the center square, notice the overshoots on the upper left and bottom right corners? (The line extends beyond the corner, up on the left and down on the right.) Start by adjusting the low frequency damping. Try turning it about 1/4 to 1/2 a turn clockwise and watch those overshoots. They should get shorter. (If they start to get longer, STOP, and turn it counter-clockwise instead.)
Try to get those overshoots adjusted back so all you see is a dot at the corner. For now only use the low frequency damping adjustment. You may need more than a half a turn - just go slow and watch the overshoot lines. So long as they are getting shorter you are OK. (If they get too long, the scanner can get out of control and go ape-shit on you. That's bad.) You want the overshoot to stop right at the dot that is the corner. (Don't be too concerned if you start to see another line growing on the other side of the corner - we'll fix that next...)
Once you've dialed in enough low frequency damping to get rid of those overshoots, look very carefully and see if the line segment got "thicker" beneath the corner at the upper left, or above the lower right corner. By "thicker", I mean it will look like the beam is re-tracing itself for a short distance. (Or if you see a second line segment roughly parallel to the one connecting the corners.) If you see this undershoot, you'll need to add a small amount of high frequency damping to get rid of it. BE CAREFUL! Small adjustments only. It may only take 1/4 of a turn or less. Again, try clockwise first, and if the undershoot gets worse, go the other way. (The early DT-40 amps had backwards pots on them, so turning them clockwise would mean LESS damping, which is backward...)
When you're done, you want to see a nice clean dot at the corner with no overshoot or undershoot.
Once you've done this, take another picture of the test pattern and post it here.
Adam
ok thanks,
am i being stupid which one do i tweat to make the frame wider?
ok i tried adjusting the position scale and position balance but that didnt make x wider???
i tried the low freq damping and that didnt seem to do anything either
some pics
http://i80.photobucket.com/albums/j1...s/20112007.jpg
http://i80.photobucket.com/albums/j1...0112007001.jpg
http://i80.photobucket.com/albums/j1...s/DSCN7268.jpg
http://i80.photobucket.com/albums/j1...s/DSCN7269.jpg
shame my green laser is crap
Andy, the pot marked input gain will increase the scan size.
Go easy tweaking pots, until you totally get what Adam said in his quick guide to tuning above - you'll let the smoke out of something :eek:
https://home.comcast.net/~djzurcher/DT-40amp.jpg
ah ok cheers
im taking it very easy dont worry
leave offset, position scale, and postion balence alone, those are factory tuned for each galvo, !! You want to bring x axis size aka input gain up a little until the squares match.Quote:
Originally Posted by andy_con
Steve
im convinced twisting the popts does nothing at all!!!
maybe its just me
ok the input gain took alot of turning just to get the image wider
but looks much beter now
http://i80.photobucket.com/albums/j1...0112007004.jpg
Those are probably 10 turn pots so don't expect to see much change by turning one 1/8 of a turn or so.
ah i see, so i need to turn a bit more than normal
play with gentle moves of LF and HF damping on the Y (vertical) axis and I Think your close! Do LF first. See if that clears it up, Then HF Then LF THEN HF......
then see if there is any major curvature in large diagonal lines . If so, then let us know.
Steve
this seems a useful page
http://www.laserfx.com/Backstage.Las...Scanning3.html
Yea, that's what I used as a reference to tune mine.
All this talk about tuning makes me want to attempt it as well. I have always been very hesitant about it, waiting for someone who knows what they are doing to hold my hand through the process.
Just a few questions the red glue on the pots, should I leave them off to break the glue, or is it easy enough to break the glue that it would be hard to damage them if they are on (And running) and the glue causes the screw to jump?
Just break the glue with the screwdriver when you start turning. The pot might jump a little bit, but a 1/8 turn isn't going to kill you.
LF damping is mildly sensitive, and HF damping is moderately sensitive, but even 1/4 of a turn isn't going to cause serious problems if it slips. You may not even see 1/4 of a turn on LF damping unless you're looking for it. (You'll see it on the HF damping though.)
Andy: You've still got overshoots on your Y amp. Add some LF damping.
Adam
awesome, I'll set up my projector tonight (it was down to show some friends at work) and start tuning... I am sure I will have a few questions... and I am sure (but still knocking on wood) that one of the questions I have isn't how much a replacement would cost! :eek:
is this looking better
BEFORE
http://i80.photobucket.com/albums/j1...s/DSCN7269.jpg
NOW
http://i80.photobucket.com/albums/j1...0112007005.jpg
yes better but the circle is not round and you still have the Y axis overshoots marked red
the blue marked corners also look a little off but its hard to tell with the burn of the camera and the matching corners of the outer square look ok - if you have manual control of the camera try a quicker shutter speed, tho not too quick or you wont catch the whole scan.
Rob
according to this guide
http://www.laserfx.com/Backstage.Las...Scanning3.html
figure there should be osme over shoot???
ill try for better pics ;) just using my n91
thats as maybe - but not that much :)
R
Also it can really help if you turn some more lights on in the room, that way the laser wont over expose the camera so quick.
sorry like i say im just using my n91 ill try my n95 instead
ok did a bit more tuning??? if thats what u can call it lol
need to adjust the circile in the middle now
http://i80.photobucket.com/albums/j1...0112007008.jpg
http://i80.photobucket.com/albums/j1...0112007009.jpg
here we go the circle in the middle is looking much better
http://i80.photobucket.com/albums/j1...0112007815.jpg
http://i80.photobucket.com/albums/j1...0112007814.jpg
Getting there!
Its just a case of tweaking and tweaking more. As this is the first time you are doing it - tuning virgin - then expect it to take a while but be patient, be thorough and understand what you are doing so you learn from it. Soon you will be able to tune without reading the instructions and you will intuitively know which way to turn the pot.....ok that may take quite a few goes but you get what I mean
Rob
yeah i get what you mean.
its a two man job, im gona get my dad to sit and watch. its very hard to see whats moving as it so far away.
i could do with my reds back as the dot is twice as good as my green ;) lol
My Scanners do the exact same thing! Are they dead? Might be a good excuse to upgrade to 45-60k scanners!
But a FB3's max point speed is 30k...Quote:
Originally Posted by Laser Ben
I got a feeling he may be able to piss money if he tried hard enough... http://www.technfun.com/smilies/icon_bikeplay.gifQuote:
Originally Posted by dave
hmmm piss money... I'll be right back... :rolleyes:
ok this is how they currently are. im going to leave them for the time eing, till i get a good laser where i can see the shapes mcuh better.
as you can see i have nearly a perfect circle
http://i80.photobucket.com/albums/j1...1112007820.jpg
http://i80.photobucket.com/albums/j1...1112007817.jpg
http://i80.photobucket.com/albums/j1...1112007819.jpg
So there is no way to tune galvos to higher speeds using a FB3 ?! - that poses a problem.Quote:
Originally Posted by dave
That reminds me of what was said in a tuning manual I think I found on laserfx: "tuning scanners to 30k doesn't mean they have to be run at 30k"
My scanners are tuned to 35k and personal experience is that if I design grafics that run at 15k with say 400 points per frame and I want to show the same grafic at 30k I need to double the number of points to 800 for the same 'quality' resulting in the same framerate and flicker.
For my scanners I found 18k to be a good point rate to design for.
Anyone with the same experience?
ok heres a few frames that my dt40's really struggle to display. when i say struggle i mean flickers lots
have a try see how yours do
dam will upload in a min
www.laser-man.co.uk/test/frames.zip
3 ilda files