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Galvo gibberish






DJZ

DJZ

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kiyoukan said:
Hello i recently bought a new set of galvos,
http://laserpointerforums.com/f39/fs-scanpro-20k-galvos-amps-53911.html
They look great and all my software seems fine but there is a problem.
The output is gibberish and i have no idea how to fix it.
Click to expand...

Hey kiyoukan, gibberish from a galvo can sometimes be easy to fix. First of all, do you know for sure that your software is working properly? Are you using a sound card DAC? If you have an oscilloscope, you can easily verify if the problem is with your DAC. If there is no problem with the DAC, then the problem is probably going to be with the signal wiring to the amps. Alot of times it can just be a problem with where the ground connection is attached. Take a look at this article, written by Bill Benner (co-founder of Pangolin): Projector Connections article by William R. Benner, Jr.

You'll want to pay particular attention to the star grounding technique that he discusses. Problems in the grounding can cause all sorts of problem in the images the scanners display.

Lastly, are you aware of SELEM next weekend? If it's possible for you to attend, I'm sure someone at the event will be able to get you gear working just fine.
 
kiyoukan

kiyoukan

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Well i just sold my old set of galvos but when i last had them everything worked.
also the mirrors on these things are weird my 405nm laser shine almost right threw them...
 
E

ElektroFreak

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Fortunately what you're getting isn't entirely gibberish. Since I can see the images you're trying to project clearly in those patterns, my guess is that there is a grounding issue. Have you thoroughly examined the SP20 manual? Pay close attention to the "wiring" section.. I'd double-check that you're wired up the way the manual recommends and double-check your grounds.
 
kiyoukan

kiyoukan

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Well i noticed that there were some wires lose from my sound card to correction amp.
I had bought it pre made so i am redoing the wiring and will post my results in a few.
 
kiyoukan

kiyoukan

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Okay i fixed it but i cant tell where a problem lies, i am thinking these came to me tuned but i am not sure.
Is there anyway to tell if its the amps that need to be tuned vs my correction amp?
http://kiyoukan.camstreams.com/
if you can help me it would be great
 
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kiyoukan

kiyoukan

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Okay so i checked my correction amp and its all tunned and i fixed the first problem but now to the fine tunning part.
I would like to know threw the LFI player interface how do i set the rate at which i scan?
i would like to set it to 30k
I am unsure if the galvos are out of tune or i am not familiar with the software i found a pdf for lfi player but it did not help.
I am getting closer but it still needs some work.
ilda.jpg

i put the points per second down to around 15000 and the pattern came out like it should but these are 20k gavlos so before i go messing with everything.
i want to set the output to 30,000 and the start using the pots to adjust the image?
i was going to follow this guide
http://www.spacelas.com/manuals/SpaceLas20K.pdf
 
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T

Things

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I wouldn't recommend trying to run cheap galvo's beyond their rating. THey tend to already be overrated anyway. See that circle in the square in your above pic? The sides of that circle should be touching the sides of that square, Either you are scanning wayyy too fast, or your scan angle is too large and your scanners are out of tune.
 
Grix

Grix

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I could never get the circle in the middle to work properly on either of my galvos. I was told there is a blanking problem in the ILDA pattern frame, and that it's not the galvo's fault.
 
C

carmangary

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If you were using Spaghetti to display it you have to turn optimizations off for it to appear correctly.
 
E

ElektroFreak

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kiyoukan said:
i was going to use it once i got a better set but the price went from like 90$ for 2 keys to over 100 for one and as it is i dont have much money left to spend.
Also link if someone wants to make the last of my money!
http://laserpointerforums.com/f39/wtb-galvo-tuning-service-54385.html
Click to expand...

In all honesty I wouldn't tune those galvos. Aside from the fact that there is no blanking, your test frame looks pretty typical of systems using a soundcard DAC, albeit that it looks like you're running a tad faster than they are tuned for. You should get decent-looking output with a pattern like that once you have blanking sorted. Along with Things I don't recommend tuning them to run faster than they are rated, and I hold by the principle "if it ain't broke, don't fix it".. Just my $.02. For the record your galvos are tuned for 20k@8deg, so unless you're scanning at an 8deg scan angle your pattern will appear as though the scanners are running faster than they were tuned for.
 
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E

ElektroFreak

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There should be some sort of image size adjustment in your software. This is what controls scan angle..

Here's a page from Pangolin regarding calculating what your scan angle is based on measuring the image size at a given distance from the galvo mirrors: http://www.pangolin.com/userhelp/scanangles.htm
 
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Eudaimonium

Eudaimonium

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I could be wrong here but I you folks are all going into wrong direction ...

It would appear that you do not have any modulation on your laser what so ever, your laser never actually turns off , in very first view of the scanned imagine I can see that there is a sine wave drawn and I can see the path where galvos are returning to starting position and then back on the begining of wave.

You sure you modulated your laser?
 
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