My laser engraver from 0 knowledge to 32.461% .... probably

[BobbyW]

Thanks Art . I will check that out ,, some test will arive now
By the way , i don't use any gearotic software than "free auggie " but still like that , i buy a license today , just to support you awesome work .
You deserve it .
See a later , Bob

[BobbyW]

Ok , i figure out how motors settings work . Still exist alot of improvements but , time by time i will learn them. I have a question about PWM power. In engine /planner config , you set the min and max setting of you lasser and also that set the limit of you laser power . So in laser panel the control of laser power will go on linear percentage between that settings ? Like example , my laser 100w , i config in planner/config at ,max 10 , so in laser panel if i put on 50% power  i will have 5W normal ,what i ask is  i will have linear scan in range of 10W configured in planner? The laser power variable is integer or float ?
I ask because my laser seems is to powerful on engrave and i need to play between 2.2 - 2.4% laser power , 0.1 percent will burn literal'y . I have set in planner config at max 80%.
Thank you
Bob

[ArtF]

Hi Bobby:

>>Like example , my laser 100w , i config in planner/config at ,max 10 , so in laser panel if i put on 50% power  i will have 5W normal?

Yes. PWM(Tickle) sets a tickle pulse, usually set to 2 for 2ms of tickle.
PWM Minimum is the min power at which laser will turn on.
PWM Max is max power ( Usually 95 - 100)

>>what i ask is  i will have linear scan in range of 10W configure d in planner? The laser power variable is integer or float ?

  It is integer, 0 - 100.

>>I ask because my laser seems is to powerful on engrave and i need to play between 2.2 - 2.4% laser power , 0.1 percent will burn literal'y . I have set in planner config at max 80%.

  Usually this is moving too slow. Power and speed are related to stop burning. For resolution
you want as high a power as possible without burning, the lower your feedrate, the lower you
must set your power. How fast are you going? What setting is your feedrate?

Thx
art

[BobbyW]

Hi Art . I try different feedrate's of course, still lerning in motor config , making mistakes so easy to figure out what happen inside.
My laser can go very fast , still on reverse move , the return of any axe was very brutal , can hear the motor move . I figure out is where "jerk limit " come in action . I have right ?
And about my config i put some pictures below . I manage to build a good PWM indexer for my source , " like you know that crap source have strange low impedance " but on my power source documentation is written >20Khz frequency
https://www.google.ro/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwiokPXMtv7mAhW2AWMBHaACBzwQFjAAegQIBRAC&url=https%3A%2F%2Fstorage.ua.prom.st%2F913343_hy_80.pdf&usg=AOvVaw0I8535iQcYyogTljKpu6_Y
Now the question in my head , i don't know the internal input capacitance on my source , to put a good PWM , to low or to high PWM frequency set will fail in non linearity power (if the source can't manage that) but thinking at analog , if low capacitance is , will be ok .
Now i set to 50khz .
Still i need more than 300 override percent to have a good move , not very slow.
And about "tickle" , I don't realy know what's mean the word. Sry my english. But i assume is like a STB power , always keep laser prepared to shoot. Is correct ?
Now i set to "0" i didn't seen to much difference on.
Also below on the picture my first test on my wife pic 
Thank you
Bobby

[ArtF]

Pretty good..

  Yes, Tickle is for pre-ionization of the laser, just keeps it ready, its not
needed on all lasers. You are correct about jerk, if the axis is loud and jerky, lower the jerk limit..

PWM frequency typically wont matter, most power supplies use it only as
a voltage averaging scheme, so 20khz or 5khz will usually be the same result,
but only testing will tell.

What power is your laser??

Art
.

[BobbyW]

What power is your laser??

Hi Art
My laser is 80W , and ,was my mistake about the source control. Wasn't broken or bad designed, it is set internaly at 40% power when nothing connected on input. I put some photos below.

PWM frequency typically wont matter, most power supplies use it only as
a voltage averaging scheme

Yes indeed , usual don't , but , depend of internal capacitance of source input , that can give a exponential voltage or just non linear.
Also now i read on PDF is only 20ma my reference 5V output . That can give me very bad pwm>vcc .
On begining i was able to pull down the residual input voltage , and use analog input as PWM . Now i try different trick , i let the source analog input limited at 40% and i connect my PWM at TL input , and it working , but the same , i can not tell the difference . Without osciloscope i cant tell if is linear or not, mostly because i didn't work for years on this machine , i just build it for fun . Still the photo look more linear like that . Right now i don't realy know what option is better to use , analog input or on TL.
The capacitors in simulation are 100p, 1n , 100n , resistors are visible
Thanks
Bobby

[BobbyW]

I forgot to say about simulation . Like you see , is simulated 3 different internal capacitance at 5 and 20khz , also different internal resistance , and the result are very different , first on timing of VCC increase and second on linearity. I think that is my source problem not auggie or config, because doesn't matter how much i will try , seems the min-max power will change between some % of my laser panel set. I need to fix that first . I don't think is feedrate or other problem , is just no linear PWM to V caused by wrong adapting impedance .

I thinking to order that two pieces. Will give me a full control with perfect adaptive impedance set min max easy to protect laser, also rid out of that 40% residual input voltage .
https://www.renesas.com/us/en/doc/YOUSYS/document/003/r08ds0107ej0400_ps_family.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2644.pdf
thx
Bobby

[ArtF]

Hi Bobby:

  I agree with your point, and using TL is probably fine, at least your PWMing a known analogue input.
It may, in the end, be a nonlinear voltage, but its also hard to say how that affects the linearity of the
laser output.

  One good way to tell is to download a greyscale form the internet and have auggie make an engraving
for it, you can then at least see the linearity of depth between grey scale set points. Its what I do
when I want to check linearity..

Art

[BobbyW]

  One good way to tell is to download a greyscale form the internet and have auggie make an engraving
for it, you can then at least see the linearity of depth between grey scale set points. Its what I do
when I want to check linearity..

Hi Art
Yea , totaly agree with you also. I do what you say me , i never think on that , i based on my calculation . And i put some pictures below.
Like i says i dont have my osciloscope here , but i can do some test on low frequency max 50khz. And i saw the problem , " i hope will be that " , like you see in photo
the voltage from PWM don't reach the good values as in my test code. I got maxim 3 levels as you see.
In the begining of the test i has 1000 feed , 400 percent and engine are configured as 1000. Using TL input , and stable vcc on analog input "1v" set tickle as 1 (if i set 0 , same 3 levels , if i set 1 he burn a small line on the return, if i set 3 he burn continuously , to high startup). Ignoring that line burning on return axes was close to more than 3 levels.
Trying on TH ,... no way to burn in any level, only 2 levels 0 and max set in power slider.
Trying with different PWM frequency , almost same result , one more bad than other .
Im a little confused right now.
Can you send me a good GCODE that you use as grayscale test ? Maybe my is not in full range of grayscale. I generated with auggie of course. Just to eliminate that option.
I already order that DAC converter and mos optocuplers , anyway are nice IC and i can use in the feature on many app.
Thanks Art
Bobby

[ArtF]

Hi Bobby:

Enclosed is a grey scale augment and its photos.

A couple of items..

The 400% is a feed-rate override, useful if a program Gcode calls for 1000, and you want 4000. Otherwise, leave override at 100% and just type in 4000 as the feedrate, probably more accurate  that way.

2)
    Auggie can only send numbers from 0-100 as power. So when you limit it to 32% by the laser power
in auggie you can get only 32 different PWM levels. This is unfortunate for high power lasers as it reduces the
resolution as you lower the laser power %.  I use an arduino to receive the pwm and allow me to adjust its
% before it goes to the laser. The arduino can subdivide in 100 steps. SO I set laser power to 100%, then
tell the arduino to adjust down to 20%. The output is then 100 steps from 0 - 20 instead of only the 20
steps Auggie can do by itself. The arduino project is published on this board as well if youd like to make
a similar board. This allows you to override the 0-100 steps the pokeys can do to be 100 steps of any %.
  So this arduino takes in 0-100% pwm from auggie set to 100%, and outputs 0-xx% as set on a lcd
connected to the arduino and sends a new pwm to the laser.

  You can see the project in the auggie topic I think under pwm control.

3)
The faster you can go the better, I typically run at 8000 or 10000mm/min , this will allow you higher power
and thus higher resolution in power steps.

  You should see a pretty good grey scale when you sort out the pwm.. Its looking good though..

Art