Laser is giving constant power even through white space

For some reason I am getting a constant power supply fed to my laser even through the whitespace of my burns. In the picture shown below, the “h” and “n” from top to bottom are set at 100%, 80%, 60%, 40%, and 20%. The “h” speed is set at 3000mm/m and the “n” speed is set at 1500mm/m

as you can see the problem is more prominent the slower my laser moves. PWM seems to be working fine because Im getting a variation in burns. I have “constant Power Mode” deselected in my cuts and layers tab, my $32 laser mode is on, and my $31 Min power is set to 0. Im not sure what else to do. Is there a min power setting in lightburn that im just missing?

here’s what im running

Waiting for connection…
ok
[AUTHOR: ORTUR]
[MODEL: Ortur Laser Master 2]
[OLF: 142]
[DATE:18:41:30 - Dec 15 2021]
[VER:1.1h.210324:]
[OPT:VNZHI,99,512]
Target buffer size found
ok
Homing
ok
$$
$0=2.000
$1=25
$2=0
$3=0
$4=0
$5=0
$6=0
$10=3
$11=0.050
$12=0.002
$13=0
$20=0
$21=1
$22=1
$23=7
$24=600.000
$25=3000.000
$26=100
$27=3.000
$30=1000
$31=0
$32=1
$33=500.000
$50=0
$51=0.000
$52=0.000
$100=80.000
$101=80.000
$102=80.000
$110=9000.000
$111=9000.000
$112=1200.000
$120=2200.000
$121=1800.000
$122=2500.000
$130=400.000
$131=430.000
$132=1.000
ok

If it were working correctly you wouldn’t have the burn in an area that wasn’t intended. lol


Do you have a voltmeter to check the pwm?

You can also check both ‘S-value max’ and $30 are set to the same value.

As you pointed out, the power is changing. If the numbers are set properly it would have to be something the pwm is doing.

If it’s powered up is the laser on when not running?

I’d check the pwm voltage…

Good luck

:smile_cat:

S-value Max and $30 are both set to the same value (1000) and the laser doesnt turn on when homing or manually moving the gantry around with the lightburn controlls. It comes on right after I hit play, and stays on through all whitespace traversing. even the initial G0 move to get into position before the burn even starts the laser comes on.

If possible I’d check the pwm to ensure it’s turning off, sounds like it isn’t.

A voltmeter should show if it’s in the same state in idle (when it’s not firing) to when it’s doing a white space move.

I don’t know these controllers as well as some.

I’m hoping @OrturTech, Gil, will find this. He’s good with these and can probably advise you better than I.

Would have been the best place to post… maybe someone will move it over there…

Good luck

:smile_cat:

Can you save the gcode for an example burn? Can check to see if the commands to the laser are correct. If they are, then likely a hardware issue.

I think @jkwilborn’s pwm voltage check would be good. This will additionally isolate if the issue is the controller sending the wrong voltage or the laser module not shutting off even with the right voltage.

Also, what’s the history of the laser? Is this new or had this previously been working correctly?

@berainlb Thank you for the response, here is a snip of a sample burn.

00 G17 G40 G20 G54
G90
M4
; Scan @ 1500 mm/min, 100% power
M9
G0 X1.4802Y5.5655
; Layer C00
G91
G1 X0.0098F59.055S0
G1 X3.5S1000
G1 X2.1752S0
G1 X3.5S500
G1 X2.0686S0
G1 X3.5S250
G1 X0.0099S0
G1 Y0.0059S0
G1 X-0.0099S0
G1 X-3.5S250
G1 X-2.0686S0
G1 X-3.5S500
G1 X-2.1752S0
G1 X-3.5S1000
G1 X-0.0098S0
G1 Y0.0059S0
G1 X0.0098S0
G1 X3.5S1000
G1 X2.1752S0
G1 X3.5S500
G1 X2.0686S0
G1 X3.5S250
G1 X0.0099S0
G1 Y0.0059S0
G1 X-0.0099S0
G1 X-3.5S250
G1 X-2.0686S0
G1 X-3.5S500
G1 X-2.1752S0
G1 X-3.5S1000
G1 X-0.0098S0
G1 Y0.0059S0
G1 X0.0098S0
G1 X3.5S1000
G1 X2.1752S0
G1 X3.5S500
G1 X2.0686S0
G1 X3.5S250
G1 X0.0099S0
G1 Y0.0059S0
G1 X-0.0099S0
G1 X-3.5S250
G1 X-2.0686S0
G1 X-3.5S500
G1 X-2.1752S0
G1 X-3.5S1000
G1 X-0.0098S0
G1 Y0.0059S0
G1 X0.0098S0
G1 X3.5S1000
G1 X2.1752S0
G1 X3.5S500
G1 X2.0686S0
G1 X3.5S250
G1 X0.0099S0

I can see the the G-code is telling the laser to output the correct power. i did put a Multimeter on the PWM like @jkwilborn suggested and it’s not a constant power like i thought it was, but its also not turning all the way off either.

also a new issue has come up. now even when i’m jogging to a position the laser will fire throughout the whole movement and then turn back off when stationary.

As for the history of the laser. It’s about 2 years old and Ive done a bit with it. If i had to guess id say about 150-200 hours of burning. im not a professional running it constantly or anything just a hobby guy making things with spare time. we just moved about a 2 months ago and before the move I had just finished an 8 hour burn Cornhole Board and it worked perfectly. so after 2 months of being packed up I finally get around to unpacking my laser and it starts with this mess.

Thank you both for your help so far.

I concur. So likely not a software issue.

What is the measured voltage at 0% (S0)? Typically anything under 0.8V should register as off for TTL.

I’m going to assume it measure okay and the that fault is in the laser module which is typical for these type of failures. Failure at 200 hours is not at all uncommon although I suspect in this case the issue is not with the diode itself but rather then laser control board.

at S0 the voltage is reading about 8v. at S1000 it reads 11.5v. I also just found and did a secondary PWM test, with the laser completely unplugged from 12v source, and only plugged into the USB on my computer, the PWM should read 0.0v but it reads 2v. I think its now safe to say that my motherboard is not working properly. Thank you for your help.

Most expect the pwm to be ttl compatible. Over 10V isn’t…

:smiley_cat:

sorry i was taking the voltage reading from the wrong spot. S0 is 1.4v and S1000 is 3v. still telling me my motherboard is sending the wrong duty cycle to the laser even tho G-code states otherwise.

Hmm… this range is close enough to thresholds where I don’t feel super solid about the diagnosis. I don’t suppose you have a scope to be able to measure this more closely?

Also, does your 100% seem less intense than before?

Or do you have an alternative way you could test the laser module independently to confirm? Also, while you have your meter out you may want to test the power supply to make sure it’s functioning correctly.

I suspect your conclusion is correct that the controller is outputting a bad signal but not certain. @jkwilborn may have a stronger opinion of it so let’s see.

Is he actually changing the S-value max setting… ?

I’m not clear what he’s up to …


I would not do it that way, I think you get unpredictable results. First, unplug the laser power, you don’t need it to check the pwm.

  1. Set it up like it’s supposed to be, in actual use.
  2. Use Lightburn to create three lines - here’s a one liner line.lbrn2. Just dupe the line two times.
  3. put each on a separate layer.
  4. set one layer as low as possible, 0 if you can the next at 50%, then the last at 100%
  5. any speed will do, probably the slower, within reason, the easier to manage.

Run the job whilst measuring the pwm.

Expect it be low, then 1/2, finally full ttl voltage… 5v … or whatever order you have them execute.

Apply the KISS principle in all cases … :crazy_face:


I keep that ‘line’ in my ‘templates’ directory, use it all the time. Good ramp test, cut speeds and feeds.

:smile_cat:

To my understanding, no. He’s just changing power % which translates in his case from S0 to S1000.

He’s getting 1.4V at 0% and 3V at 100% power out of the controller leading to the idea that the controller is misbehaving.

Saying this would have made more sense…

:smile_cat: