# Problems with laser power scale from 500 mV at 10% of power setting

Hi, I have been using Lightburn since 2021.
Fantastic program!!! I updated the version from LightBurn 1.2.00, to the current LightBurn 1.5.06.

Now the laser goes to full power when it is at 10%.
I can’t understand where I’m wrong.
Below are the parameters in mVolts detected by the laser:
00.00% = 50mV
01.00% = 500mV
10.00% = 5000mV
20.00% = 5000mV
100.00% = 5000mV
below are the RGBL parameters:
\$\$
\$0=10
\$1=25
\$2=0
\$3=0
\$4=0
\$5=0
\$6=0
\$10=255
\$11=0.010
\$12=0.002
\$13=0
\$20=0
\$21=0
\$22=0
\$23=0
\$24=250.000
\$25=3000.000
\$26=250
\$27=2.000
\$30=1000
\$31=0
\$32=0
\$38=10
\$100=80.000
\$101=80.000
\$102=80.000
\$110=3000.000
\$111=3000.000
\$112=1000.000
\$120=20.000
\$121=20.000
\$122=20.000
\$130=650.000
\$131=650.000
\$132=200.000
ok
Has anyone had the same problem?
Do you have any advice to help me figure out where I’m going wrong?

I would say first and foremost this is hardware and not software issue.
Lightburn only issues a Svalue command which your machine then translates into a voltage and PWM signal

However, the primarry issue is you are assuming the power scale is linear, when in reality it “should be” but isnt

Usually the bottom 10% and the top 10% of the scale are non linear
In other words, 0 - 10% the laser might not even trigger correctly (in some machines) and in diode lasers nrmally it will be a non linear response, above 10% you start to get a bit of linear response.

90 - 100% theres basicly, on average, no change in power what so ever

I assumed a software problem, I had not detected such a problem in the old version of Ligtburn, I do not exclude the possibility that the hardware was damaged at the same time.
regarding the power scale, I am aware that the relay value cannot be linear with the theoretical value.
My problem is that the laser outputs 100% power, with only 10% set to the level.
Below I correct the voltage values ​​found based on the % of power set:
000,00% = 50mV
001,00% = 500mV
010,00% = 5000mV
020,00% = 5000mV
100,00% = 5000mV

You are in M3 mode, but i am uncertain what control you have

Something you need to check too in EDIT → Device settings
Whats Svalue max?

Sorry if I didn’t thank you immediately for the support you are giving me.
Thank you.

I don’t know what the M3 mod is.

Regarding power limits, hp set at
\$30 = 1000
\$31 = 0

1 Like

ok so here is the problem
You have a mismatch of factors, although not necessary the cause of the problem might indicate it

You configured your machine on GRBL M3 mode
M3 mode - USUALLY - has Svalue Max 255

Your motherboard however has Svalue max 1000
So what machine is expecting , and what lightburn is sending might be a mismatch

Also doe your motherboard not support \$32=1?

did you mean the screenshot of the screen I attached?
I’m sorry but I don’t know what the EDIT → Device window is.

try this, Edit top menu, then Device settings

so I just set the parameter \$30 = 255?
I have always had the parameter \$32=1, I changed it to 0 this morning to do some tests

i wouldnt know as you have notyet shown me the Device settings screen

I’m ignorant, sorry, I don’t know what the device settings screen is.
What do I have to do to see this screen?

Click the Wrench icon at the top

Then take screenshot

ok so heres what i would suggest

Click devices → delete your profile

Click Create manually
GRBL (TOP of the list, not LPC nor M3)
650x650
Next next done

\$32=1
Press enter

Edit → device settings confirm your Svalue is 1000

When all done, try a new engrave

A thousand thanks,
problem solved!!!

awesome news

1 Like

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