Digital scanner amp

[FourDee]

I know that many people here are analog-minded, but I was wondering if there would be issues with making a digital scanner amp.

In my mind this is basically a PID-controller.

I saw that Cambrigde Technology has some digital amps, but i've seen none in lasershow use.

If it would be possible to build such an amp, the computer could be directly interfaced to the amp.

Comments?

[drlava]

You will still need a DAC to control the laser modulation, so until the lasers are digitally computer interfaced as well, the simplest solution seems to be to keep the drivers/output interface on one multipurpose dac board. Another issue is the galvo feedback is analog so you either need a high dynamic range, high speed digital position feedback solution or an ADC to feed your digital PID.

[ajohnson30]

Thinking about it a slightly different way, how is this any different? It sounds like you'd just be making the DAC be part of the amp instead of a discrete module. Unless there's some digital motors I'm unaware of, there's always analong in there somewhere.

[LesioQ]

Aim for perfect A-D marriage - go DSP ! Best solution, self tuning (if You like programming). Everyone can find a pleasure in pain

Piotr.K

[Pangolin]

Digital servo amps do indeed exist for scanning systems. We've done digital servos before at Pangolin, and I worked with Randoph Hoche (smartmove gmbh and designer of the ditigal amp being sold by Cambridge) to improve his design. General Scanning also has a digital amp as part of their "Lightning" series. And all of these are self-tuning.

The problem, as I see it, is one of economics. It is still less expensive to make an analog servo than it is to make a digital servo. Plus, all of the digital servos out there to date have an inferior sample rate (in my own personal opinion). It costs even more money to push the sample rate higher.

Self-tuning isn't as important as it's cracked up to be. If you have a properly designed servo amp and scanning system it is tuned once at the factory, and never again. Ask the people at Disney how often they tune their scanner amps for instance...

Best regards,

William Benner

[carmangary]

Hey Bill, on a side note, do you get a lot of work from Disney? Just curious since you're in Orlando. Last time I was at Disney I didn't notice any use of lasers, though. Seems like they would, though.

[aijii]

Last time I was at Disney I didn't notice any use of lasers, though.

Maybe thats because their scan systems need a tune ?

[FourDee]

I was just thinking that this would be kind of nice to play around with. I thought of dsp, but maybe it's a bit overkill for this.

I know there will always be analog in this, but since most of the projects I make are digital ones, I thought I'd have a go at this.

Does somebody know what the advantages are of using a digital amp from ct for example?