The Intensity control on the ILDA pinout

[buffo]

which other controllers

Ouch! But yeah, I hear you.

I would not buy easylase anymore :http://www.photonlexicon.com/forums/...50&postcount=7

Well, apart from Joachim's motivations, I also have a problem with the lack of shutter signal support, so yeah, the Easylase is out.

Riya maybe?

That's one of the others, but there are plenty more. Just curious if the other controllers support analog or TTL intensity... (Obviously controllers like Full Auto and Alphalite, which are TTL only to start with, will only support TTL.)

Adam

[riyalasers]

All versions of RIYA controllers have analog outputs on color lines.

Multibus serie have some additional options:
- analog or TTL level on color outputs (with regulated threshold for TTL);
- separate level signal inversion on every color outputs


Ihor

[Pangolin]

Regarding the Intensity signal, I can tell you the intention, and then give some advice. I can also, of course, comment about how it is used from the QM2000.

Before giving further comment, I'd like to remind everyone that I was Technical Committee Chairman all during the drafting and final publishing of the ISP standard. Not only was I present during all of the meetings, but I have all of the email communications that lead to the standard. My point is -- the words below aren't just a bunch of speculation.

First, if you look at the pin-out of the ILDA connector, you will notice that signals are arranged in "pairs". They are arranged that way so that ribbon cable can be used, and crimped onto DB-25 connectors. Moreover, the signals are arranged in a kind of order indicating "priority". There was recognition that some projectors would not use all signals. For example, some projectors are simply X and Y "mirror movers". And other projectors are full-blown RGB projectors with additional equipment for stereoscopic projection. People could use the “pairs” that they need, by simply tearing off pieces of ribbon cable.

The idea was that for people who had the absolute most basic projectors, they would use only the first four wires (X and Y differential). The next logical step is "blanking" -- not necessarily intensity, but "blanking". In the early days, some people used the term "blanking", but during the drafting of the standard it was changed to "intensity" only to indicate the HIGH state of the signal. (The HIGH state does not indicate that the beam is off, but rather that the beam is on, hence it is intense, not blanked.)

It was envisioned that X, Y and Intensity would only be used for projectors with scanner blanking. DPSS lasers were not in use at the time, so only scanner blanking was envisioned for the "intensity" line (if people used only the first three pairs of signals). The next logical extension is to have an interlock which could be interrupted to prevent the projector from outputting a beam, hence, that's why the interlock signals are next. And, the next logical extension is red, green and blue.

So that's a description of the signals, the order, and how and why they are stacked the way they are.

In terms of "analog" or "TTL", I am not sure that the 1999 standard is 1000% clear about this. I can tell you that the intention of the "intensity" signal was to be used with scanner blanking and also to help out with PCAOMs. While it's vaguely possible to do fading with scanner blanking, as a rule, it doesn't work very well.

Secondarily, when used with PCAOMs (far more common at the time of the drafting of the ISP standard), the "intensity" signal was used as an additional input to PCAOM drivers, and gave an additional 30 to 40 db extinction ratio. So, using this additional input improved the blackness that you get with blanking. This additional signal used for PCAOMs is most definitely a TTL signal.

So, basically, given the intention of this signal and also given the most common use of this signal during the drafting of the standard, I would say that the behavior of this signal should be TTL in nature.

As an aside, one hugely frustrating thing that I keep saying over and over again is that after I left the technical committee chairmanship, almost nothing has been published on these standards. Work HAS BEEN DONE on the standards, including work by me, Patrick Murphy and others, but this work has not been published. Things have been clarified in later drafts of the ISP standard, but they haven't made it out into the public, I would say largely because of political reasons (within ILDA). Because of that, good folks such as yourselves, looking for good answers are still basically in the dark. I personally can tell you what's in the new standards and I personally can give you advice, but there is nowhere else that people can go to get the information.

Getting back to the main point, people should make the broad assumption that the intensity line has a behavior that is TTL in nature. That is the DEFAULT behavior of the intensity signal coming from the QM2000.

However, if we are to talk about the QM2000, there should be a recognition and understanding that this is one of the most versatile laser controllers in the world. The QM2000 can actually control up to 8 separate wavelengths (using the intensity and shutter signals as separate wavelengths) and any and all of the QM2000 color signals (including intensity and shutter) may be “trained” for any particular behavior. So, for example, Intensity could become another color signal if desired, it could become an analog signal representing the overall intensity of the light being projected, or it could be a TTL signal representing intensity or even “blanking” (inverted intensity). Non-Pangolin-users should not make any assumptions about perceived limitations of any Pangolin hardware, nor should they attribute any default behavior as “the Pangolin way”. Stated simply, “The Pangolin way” is to provide maximum flexibility and, at the same time maximum simplicity and ease of getting quality results. When you receive a Pangolin system, it will work out of the box, because we've got the most experience with laser projectors. We know what the signals are supposed to be used for, and we know how projector manufacturers are using these signals.

As for advice -- if you've got a single color laser projector and you want to use a Pangolin product to drive it, this is no problem. With QuickShow, the QuickSetup wizard will figure it out and you'll be off and running. And with LD2000 there is the "Palette setup wizard" which will get you up and running, regardless of which signal your laser is connected to, and even regardless of whether or not your projector has inverted behavior on the color signals (remember, maximum flexibility and ease of use).

If you've got a single color projector and you're driving with someone else's software, it's not going to be that easy... The best thing to do would be to use differential receivers on red, green, and blue and then feed the output of these differential receivers into diodes for the red, green, and blue inputs and "or" these signals together with diodes, and then take the common cathode of the three diodes and drive your single color laser that way. (Gosh, seems so much simpler if you have Pangolin softare... )

Best regards,

William Benner