Lightobject new DSP laser controller card

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Wed Aug 23, 2017 9:38 pm

Is implementing the Z-axis control on the radar yet?

Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Wed Aug 23, 2017 10:25 pm

Not sure what you mean?

Marco

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Sun Aug 27, 2017 9:06 am


Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Sun Aug 27, 2017 12:18 pm

EPlog system is a different machine that you are trying to compare with. They don't have laser tip but open case design. For most laser machine, you need to change laser tip when changing focus lens with different focus point. Otherwise laser beam will hit the laser tip. I just talked to the programmer to add a feature by moving the Z bed to a specific location through "dial" by enter a value to an input box under the software. Hopefully it can see it in action soon

There is no way you can do 3D engraving or true grayscale with a regular CO2 laser tube driving by most DSP controller available in market. The EPlog system is running in RF laser tube. It's beam is much smaller and the reaction time is faster than a CO2 tube driving by high frequency DC pulse. The Eplog controller cost over $2000 so, it is not a good match to compare the Eplog controller to our T9 or to X7. Even the Ruda R5 or Leetro 6535 can't handle greyscale or "2.5D" engraving.

Btw, we will consider your wise suggestions on new features, but we can't and we won't guarantee that we can do it. I will only make suggestion to the programmer of the card supplier. Plus, I personally won't guarantee how good of a new feature being implemented. So, no blaming here like a folk complaining the Z table on X7. I have no right or privilege to force what was the programmer doing because I don't own them. However, I will try my best to make good suggestions through communication with the programmer or with his boss in China


Marco

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Sun Aug 27, 2017 4:34 pm

Z-control needs to be as I described. There should be a menu of lenses with independently programmable focal points, which are actually distance from the z-home switch. e.g. a 2" lens may be 16" from the z-home at the bottom. That's "zero" focus, and the readout should read "0". This is the bd, the bottom of the work. A 4" lens might be 14.1" because it's not exactly 4".

Lens cannot change with pen color. However, material height can. Selecting "0" for thin paper with a 2" lens makes the z table jog to 16" from the Z-home switch and it will read out 0. If you engrave 1/2" wood in "blue", you enter 0.5" on the blue pen and the table will jog 15.5" from Z-home and read out "0.5".

Lasers cut much faster in thick material if you put focus in the middle. This works as long as the air assist cone does not collide. You would set 0.25" for 0.5" wood, but only on the CUT color. That is why they must be different. Blue pen focuses at 0.5" to engrave on the top, then yellow focuses at 0.25" to cut. This is one reason why focus needs to change.

Other artists WANT wider vector lines so they can make marks you can see across the room. So they might enter 1" for 0.5" wood for one group of lines (speed slowed down to get more burn), but other focuses for different thicknesses. This can be 100x faster than rastering.

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Sun Aug 27, 2017 4:48 pm

On 3D:

(Did you mean "Epilog"? Can't find anything under "Eplog", but Epilog doesn't sell controllers AFAIK)

I do work with RF lasers. AFAIK glass DC are slower to turn on-off but the need to get fast switching from the tube isn't that high for two reasons. One, the speed can be slow. First is the tube's power and desired cut thickness, but also the user can select fewer lines/inch if they need to slow down the cut to a speed the tube can switch at. It rarely affects the end quality. With a beam 0.010" (won't always be at the ideal focal point), doing 1000 lines/in is pointless. The resolution quality peaks out at about 300 lines/in even if you're fanatical.

Second, the tube may not have to change sharply anyways. If we are burning a graphic and the tube takes 4ms to fully change power levels from 0% to 100%, you may well still get a high quality rendering pushing through pixels at 1ms/pixel. Only the transitions from a white to an adjacent black pixel will be a slope instead of a vertical line but that may need a microscope to see. A 25%-black pixel next to a 35%-black pixel followed by a 45% black pixel will not have any discernible rendering error because of the "slow" tube.

In fact, if we have a tube that can only switch on/off at 1KHz at most (0.5ms on/0.5ms off achieves a full-on and full-off on the laser output) but feed it a 5KHz PWM, that may not be bad. It may produce a smooth 50% strength beam and that's the intended output when we have a 50% black shade. But if the driver's input stage is digital and has a 1KHz filter on it, it may resolve to all-on or all-off with no shading.

Algorithm should be time-based instead of distance-based. If the user selects 5KHz, the beam modulates at 5KHz regardless of the pixel processing rate (resolution * raster speed). That's 0.2ms time periods. If a time period falls entirely on one pixel, you make the duty cycle equal to its blackness. If it falls 2/3 a 35% black and 1/3 on a 50% black, the duty cycle is 40% for that period (2/3*0.35+1/3*0.5).

Not all transport formats can physically handle this. It can be a lot of data and requires unusual synchronization between the a time domain and a position domain. If it gets handled inside the controller box it's not that much of a problem. If the PWM data has to transfer from the PC in realtime, there's a fundamental flaw in the system.

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Sat Sep 09, 2017 6:55 pm

Still need electrical specs for hookup. Had this card for months, still waiting on the shelf.

Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Sat Sep 09, 2017 8:47 pm

We posted the connection diagram on the manual section. It show the basic connection for a complete laser diagram

Marco

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Sun Sep 10, 2017 9:10 pm

Connection diagram does not help. Need basic electrical spec!

The "OUTPUT1". Is that an open-collector? Open-drain? Driven high/low? 5v? 24v? Is it an opto only capable of a few mA, or can I drive a relay with it?

We cannot continue to integrate this until you provide documentation!

Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Sun Sep 10, 2017 9:19 pm

I don't have those detail info from the manufacturer and I have no problem to use the out out to control an IO board or driven a SSR.The output is 5V that's all I know. The current should be 10mA or less and itis better to drive a SSR but not a relay

I really don't see the difficulty to use it to drive an exhaust fan with the output signal. Anyway, let me ask the manufacturer see if they have info to share. Stay tuned

Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Sun Sep 10, 2017 9:47 pm

The manufacturer send me a picture of the device that used to output the control signal. It is an Opto switch

57BF1642-D9A0-42D8-BD3F-E9213954A41F-689-000000935606B9CE_tmp.jpg


It look like it is an ok Toshiba TLP785
http://www.mouser.com/catalog/specsheet ... 120220.pdf

That's all I got

Dannym
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Joined: Sat Dec 31, 2016 9:42 pm

Re: Lightobject new DSP laser controller card

Postby Dannym » Mon Sep 11, 2017 10:03 pm

So it's gonna have to be open-collector or open-drain, it can't be both- which is it?

Tech_Marco
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Re: Lightobject new DSP laser controller card

Postby Tech_Marco » Mon Sep 11, 2017 10:11 pm

I don't know.

I think with your electronic knowledge you can test it and figure it out

When the output is "off", there is 5V appears on the output terminal. When it is 'On', it dropped to "0v" in respect to the Gnd

Techgraphix
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Re: Lightobject new DSP laser controller card

Postby Techgraphix » Tue Sep 12, 2017 3:12 am

Seen from the datasheet, it's Open Collector.. And according Marco's post, it also acts like one..
Nothing special about that.. smile

Kees

Dannym
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Re: Lightobject new DSP laser controller card

Postby Dannym » Mon Sep 25, 2017 1:46 pm

Is its polarity programmable? I would most likely connect that to an NMOS, so high=on, but if it's an opto in open-collector mode, "on" is low. How does that work?


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