Power output lower than

LightBurn Hardware Compatibility GRBL
1

Hi
I just adquire a Monport Grbl 1.1 k40 , the issue is that power output is lower than the power set at lightburn. I already checked s-value matching $30 machine value, and the current knob is at max, but when I start a file the machine moves without cuting or engraving and the ammeter never show more than 1mA, however if i press the laser test at the machine it pierce the blue acrylic without effort and the ammeter show 21 mA.

I tried with 60%-80% power in lightburn but is always no more than 1mA when I start the file.

I think i missing some configuration because laser seems working fine with test button.

2

Is $32=1?
And laser setup as GRBL?

3

Do you have a voltmeter? It’s relatively easy to separate the issue between the controller and power supply but you need a voltmeter.

Then we can work on what to do next…

:smile_cat:

4

hi
Yes it is set to $32=1 and device as GRBL, I also tried with GRB M3 1.1 earlier.

Here are the other varibles

$$
$0=10
$1=25
$2=0
$3=1
$4=0
$5=0
$6=0
$10=1
$11=0.010
$12=0.002
$13=0
$20=1
$21=1
$22=1
$23=3
$24=800.000
$25=3000.000
$26=232
$27=3.500
$30=1000
$31=50
$32=1
$33=1
$34=1
$35=0
$36=0
$37=1
$39=1
$100=160.000
$101=160.000
$102=80.000
$110=20000.000
$111=20000.000
$112=20000.000
$120=500.000
$121=500.000
$122=500.000
$130=300.000
$131=200.000
$132=300.000
ok

5

Even if the machine test button works ? I will get a voltmeter

6

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7

Yes, unless you can see where the electrons are going…?

Your $31 value should be zero. Did you follow the grbl setup from Lightburn?

:smile_cat:

1 Like
8

I had the same problem with my old K40, it was something to do with incorrect output voltage on an early version of the monport board, I found a solution purely by accident, when doing Material test I found I was getting good results in the power settings of 0-1% instead of 1-100 so I just increased my S-value by 100x so i could work in the apparent range of 1-100%. I have no idea if it was just a fluke or if it will work on all early monport boards, but worth at least giving it a try.

9

When you changed out the board for the Monport, did you lose your manual pot current ability?

At some point they changed how they wire these up.

:smile_cat:

10

No, did not think of that as there was absolutely not mention of it in the installation manual, and adjusting pots in above my skill/knowledge level anyway

11

I will try it, so you put s-value = 100000?

12

i set the $31 to zero, no change i got the voltmeter so what should I measure?

13

$30 is the maximum spindle speed and $31 (0) is the minimum spindle speed … in Lightburn the $30 equivalent is S-Value Max (spindle maximum value). The $ settings tell the controller the relation of what the data sent to it does.

These values are used by Lightburn to determine the generated gcode to specify a spindle speed … I.E. laser power

The link I posted in # 7 for setup of these, did you follow that? It appears not… :poop:

If you don’t follow the setup, whatever you do will not be of any value to those trying to help you. We won’t be able to tell what the issue it…

Configure it correctly and then we can look elsewhere otherwise we can’t do much to assist.

You can use your voltmeter to read the pwm output… 50% power should read 2.5V (1/2 of 5V)

Make sense?

:smile_cat:

14

In my last post I put $31 to 0 following the instructions link

15

Did you check the pwm output voltages as per the previous post?

:smile_cat:

16

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