Scanners Side by Side Video

[DanBarlow]

Disclaimer: I have tuned scanners but I'm by far not the best at it.

Yes, the drivers have gain (proportional), integral, and derivative adjustments as well as overall size sometimes.
The ILDA test pattern can help you tune the scanners to a particular point rate (30k etc) AND ANGLE.
If I understand correctly it's 30000 points per second at 8 degrees included angle (+- 4 degrees of center.)
If you have multiple different types of scanners you can set them to the same scan angle per input level, then tune them for best performance at that angle.
I think that would mean shrinking the better performing scanners to the size of the weakest set.
That means shows should look the same if you have to swap out a projector. The better ones will just be more accurate.
It would also help if you're trying to overlay multiple projectors onto the same scene.

[buffo]

Technically the scan-speed is the only variable when tuning. The scan angle that you use while tuning is not important, so long as it is low enough to be within the abilities of the scanners.

This means that if you tune a set of scanners at 30Kpps speed and 5 degrees of scan angle, and you get them adjusted so the ILDA test pattern is correctly displayed (circle just touching the center square, perfectly round, and no overshoot or undershoot on the corners of the square), then you can increase the scan angle and the pattern will stay perfect up until you reach the limits of the scanners.

At the limit point, the circle will stop getting bigger as the rest of the pattern grows, so the end result is that the circle no longer touches the center square. And if you continue to increase the angle, the circle will begin to pull apart into a spiral shape. This is why it's important to make sure you are not scanning too wide before you start tuning your scanners. (You'll never get the pattern right if you are too wide to start.)

But if you tune at 2 degrees and then increase to 8 degrees, the pattern should still look the same. (Assuming that 8 degrees is within the abilities of the scanners.) And when someone says that a given set of scanners are "30K", that means they can correctly display the ILDA test pattern at 30Kpps *and* at least 8 degrees scan angle. They might be able to scan it even wider, but if they can't manage at least 8 degrees, then they're not meeting the ILDA spec.

Likewise, to be classified as "60K" scanners, they need to be able to reproduce the test pattern correctly at 60Kpps and 8 degrees scan angle. But even in this case, it is perfectly acceptable to tune the scanners at 5 degrees and then increase the angle to 8 to test them. So long as you did the tuning correctly, the pattern should look the same at all scan angles - up to the point where you reach the scanners limit. (At which point you'll see the artifacts mentioned above.)

Note that most 30K scanners can manage more than 8 degrees. (Sometimes a lot more!) I've seen Pangolin scanners do well over 35 degrees. (!) This is actually an excellent way to compare different scanners. First you tune them all to the same speed (say, 30K), and then you display the test pattern and start increasing the scan angle until the circle just starts to pull away from the center square. That's the limit point. The wider you can scan before this happens, the more capable the scanners are.

We've done this exact shootout at the Florida Laser Enthusiast's Meetings multiple times over the years. I'm sure if you look through some of the past threads you'll find the results, but a cursory search didn't yield much apart from this video: https://www.youtube.com/watch?v=j99ZKovDWbU and this thread, which is a bit light on details: https://www.photonlexicon.com/forums...706-FLEM/page5 But I'm sure with some more digging you can find more info...

Adam

[masterpj]

Technically the scan-speed is the only variable when tuning. The scan angle that you use while tuning is not important, so long as it is low enough to be within the abilities of the scanners.

This means that if you tune a set of scanners at 30Kpps speed and 5 degrees of scan angle, and you get them adjusted so the ILDA test pattern is correctly displayed (circle just touching the center square, perfectly round, and no overshoot or undershoot on the corners of the square), then you can increase the scan angle and the pattern will stay perfect up until you reach the limits of the scanners.

At the limit point, the circle will stop getting bigger as the rest of the pattern grows, so the end result is that the circle no longer touches the center square. And if you continue to increase the angle, the circle will begin to pull apart into a spiral shape. This is why it's important to make sure you are not scanning too wide before you start tuning your scanners. (You'll never get the pattern right if you are too wide to start.)

But if you tune at 2 degrees and then increase to 8 degrees, the pattern should still look the same. (Assuming that 8 degrees is within the abilities of the scanners.) And when someone says that a given set of scanners are "30K", that means they can correctly display the ILDA test pattern at 30Kpps *and* at least 8 degrees scan angle. They might be able to scan it even wider, but if they can't manage at least 8 degrees, then they're not meeting the ILDA spec.

Likewise, to be classified as "60K" scanners, they need to be able to reproduce the test pattern correctly at 60Kpps and 8 degrees scan angle. But even in this case, it is perfectly acceptable to tune the scanners at 5 degrees and then increase the angle to 8 to test them. So long as you did the tuning correctly, the pattern should look the same at all scan angles - up to the point where you reach the scanners limit. (At which point you'll see the artifacts mentioned above.)

Note that most 30K scanners can manage more than 8 degrees. (Sometimes a lot more!) I've seen Pangolin scanners do well over 35 degrees. (!) This is actually an excellent way to compare different scanners. First you tune them all to the same speed (say, 30K), and then you display the test pattern and start increasing the scan angle until the circle just starts to pull away from the center square. That's the limit point. The wider you can scan before this happens, the more capable the scanners are.

We've done this exact shootout at the Florida Laser Enthusiast's Meetings multiple times over the years. I'm sure if you look through some of the past threads you'll find the results, but a cursory search didn't yield much apart from this video: https://www.youtube.com/watch?v=j99ZKovDWbU and this thread, which is a bit light on details: https://www.photonlexicon.com/forums...706-FLEM/page5 But I'm sure with some more digging you can find more info...

Adam

Saturn 1b can do 30kpps within tuning at 99% of full angle!
That is over 60degrees which is what most galvos are rated at because that's the angle to which they guarantee that no clipping of a beam maxing out the mirror is present.
And yes you are right as long as it's within the capabilities of the galvos and their amps then you can size without losing tuning.

[rns0504]

Just rub it in PJ I'm still waiting for mine... and I build them!

[masterpj]

Just rub it in PJ I'm still waiting for mine... and I build them!

They should give you one asap. It's always best for an engineer to not just build it but work with the equipment he builds! I mean it offers a different look and insight for new additions/tools to that product line!

[Colin290]

I have no idea if the ALK30 will be the same size as the PT30. I will probably be a way to tune the scanners to throw more or less the same size from the same distance. From what i have been reading here at PL, there is not a stright forward way doing that. All the pots on the scanner amps are used to tune the final output, and adjusting the size will result in adjusting all the other pots to balance the signal.There are some descriptions here at PL on how to tune scanners, but I have not come to that point yet myself.

Goldenstar does not sett PT - scanners, so i would not count on data from them in this matter. It might be some members here having both scanner sets, willing to set tjem up side by side to compare size.

I tried a side by side video with DT30 vs ALK30 and got a bit of a surprise when the DT30s started acting funny and blacking out during cues.. have a look here see what yuo guys think: https://www.photonlexicon.com/forums...erforming-DT30

[norty303]

If they are blacking out, I would think it's nothing to do with the scanning system, unless there is a safety board fed from the pinouts near the top centre of the driver.
The polyswitch may cut in when being pushed hard which can cause output issues.