Scannermax 506s

[absolom7691]

That looks as though they're almost about to come off. Almost certainly an electrical or mechanical fault.

I don't think this is a mechanical fault. I would also bet that it's a grounding issue. I have not had a set of scanners act the same when it was a wiring issue. Each set has always been different. My guess would be a wiring issue. The oscillation looks too low to be a tuning issue (I would think).

It's Klatu isn't it from the original, "The Day the Earth Stood Still"?

**Actually, it's Gort. Klaatu was the traveller. Gort was his robot bodyguard.

[rns0504]

Fearless, unrelated to the issue at hand, but did you switch the X- and Y- scanners? The reason I ask is the "tongue" of the mirror should be facing downward at rest on both the X and Y scanners, and in this case both are upwards, yet the scanners are "clocked" to the proper positions. This mirror set is designed to work with them in the other orientation to fully capture the beam and scan wide angles, as seen in the engineering drawing on the Compact 506 page new www.scannermax.com website.

[Pangolin]

Good spot Ryan!

He should reverse the X and Y scanners. I guess he removed them from the mount at some point, thought that they were the same, and then screwed them into the mounts later without reference for which was which. Of course that would only cause a slight problem if he had a 4mm beam in the first place, and even then only at wide scan angles.

Nevertheless, the problem you are showing there has nothing to do with the scanners, that's for sure. This could be a power supply phenomenon or something like that.

What happens if you have the amps powered, connected to the scanners, but no input at all connected to the amps?

Bill

[Pangolin]

When a scanner is specified for say 30kpps, what is the limit that a scanner is being asked to perform a step response (small as well as large)?

Great question. As discussed in my video 30K means a 2.5kHz small signal bandwidth. That equates to 300 microsecond "small step response".

The "small step response" is measured "from stop to stop" -- not from 10% to 90% as is common with normal rise-time and fall-time measurements with other signals. Some people do not know this, and measure their step times from 10% to 90% and this allows companies to exaggerate...

The next question is -- exactly how small is a small step, and that's another great question and many times the real operative question. What happens is, if you put a teeny tiny step into a scanner, that will require a certain amount of coil voltage to accomplish (related to rail voltage). Let's say "teeny tiny" requires 10 volts across the coil. And let's say you've got 30 volt rail. No problem -- welcome to the "small signal domain". So then let's say you increase the steps little by little. What you will find is greater and greater amount of coil voltage is needed to accomplish the step in 300 microseconds. Eventually you "hit the rails" and so for example, perhaps for a 5 degree step you would normally need 40 volts across the coil but you've only got 30 volt rails. Well "welcome to the large signal domain".

The scanner will accomplish all steps at 300 microseconds AS LONG AS you are in the "small signal domain". Otherwise the power amplifier saturates, and the steps will become longer and longer.

So for a "full field step" it will probably take along the lines of 1 millisecond to accomplish. And actually, it has been a while since I checked that out so "your milage may vary"...

However, one "big picture" scenario is this: While scanners from 3 separate manufacturers may be able to accomplish 30K (and 300 microsecond small steps), not all three will exit the small signal domain and enter large signal at the same place (same number of degrees). Scanners with a higher torque-to-inertia ratio and also lower coil impedance will enter the large signal domain later (at larger steps).

This is what governs the size of the "circle in the square" in the ILDA test pattern. The reason why the circle stops getting bigger is because you've run out of rail voltage and must enter the large signal domain. All scanners do this at a different place, and you can extend the size by increasing rail voltage. Unfortunately increasing rail voltage (or going to an H-bridge) increases heat of the power amplifier at a geometric rate.

At first glance a scanner that can preform a 200usec, small step response is pretty fast, but that would seem to correspond to a 5kHz signal response and that is a long way from 30,000 somethings/ sec.

5kHz is 60K, and would be 150 microsecond small steps.

Similarly, what is the diode modulation frequency range that has to be accommodated to enable 30kpps performance?

That depends on your "color shift" setting. If you have a color shift of zero, then if your laser diode driver -3dB bandwidth is 2.5kHz, then you'd be able to operate it along with 30K scanners with no color shift. If you have 60K scanners, your laser diode driver would need a bandwidth of at least 5kHz. As the laser diode driver bandwidth becomes increasingly faster and faster when compared with scanner frequency, that's when you start needing "color shift". You can think about this "color shift" is "timing advance" on an automobile (but in reverse).

Bill

PS: If you only ever had to accomplish small steps, then the servo gain can be increased and increased and increased, giving you faster and faster small steps. The only limitation would be a) heat and b) resonances. But with ScannerMAX scanners the coil has lower resistance making less heat, and we use 3mm bearings and rotors making them "stronger". It is this combination (stronger plus cooler) which allows higher scanning speeds.

[Alex_kld]

hi guys!
tell me who makes amplifiers for max 506 scanner, because pangolin sells them without amplifiers.

[Laser Wizardry]

" 15 characters"

[edison]

His question is not who makes the amps but who makes amps for them. He probably have seen that Kvant , RTI and a few others have it sorted. @Alex_kid , mixedgas can probably help you out if you want to go 506.....

[Bradfo69]

This has probably been brought up in the 30 odd pages this thread is now up to so I'm sorry if it's already been answered and it's become buried but... how viable a candidate are PT-A40 amps for modification to be used with the 506's? Anyone know?

[mixedgas]

This has probably been brought up in the 30 odd pages this thread is now up to so I'm sorry if it's already been answered and it's become buried but... how viable a candidate are PT-A40 amps for modification to be used with the 506's? Anyone know?

Best to just shoot a picture of the chip and pot side of the board and email it to Bill.
He'll know what it is.

Steve

[Alex_kld]

Thank you for your answers!
tell me, who managed to compare skanermax 506 and other scanners. now i think what to choose? buy 506 or just as well stay with CT6210 (30K)
what do you think guys?