K40 Lost power after upgrading to MKS DLC32 V2

Lasers
1

Hi all,

I’m really stumped here,

I eventually upgraded my K40 to a MKS DLC32 v2, did the wiring like my crude drawing attached.

Problem is before I could easily cut 3mm MDF, now no matter what I try I can get it to cut through??

Using Lightburn, everything wiring wise seems to be fine, as I increase power my ma meter goes from 0 to around 22 ma, so power seems fine

What am I missing?

Thanks!
Dion

Wiring
Wiring659×694 199 KB

2

Just also, I can cut and engrave, change power levels and the actual power is changing, so I can’t see how this is a wiring/software issue?

3

While running a job to cut, with a DVM measure the voltage relative to ground on the IN pin of the LPS. 5V would be full power.

1 Like
4

Ok so basically between the G and In that is going to TTL on the MKS?

And if it’s not 5v?

Thanks

5

Screenshot_20231207-104453
Screenshot_20231207-1044531079×1508 263 KB

The ESP32 being a 3.3V part makes me wonder whether it puts 5V out. I see one mention of 5V there but I’m not sure it’s right. It talks about input of 5V so I think it means it is 5V tolerant when used as a leveling input.

interface
interface928×802 643 KB

Here’s the latest schematic gift that board: https://github.com/makerbase-mks/MKS-DLC32/blob/main/hardware/MKS%20DLC32%20V2.1_003/MKS%20DLC32%20V2.1_003%20SCH.pdf

1 Like
6

I am assuming that your setup is :

  • Drive IN with a PWM signal to control power
  • Drive L as an enable?

Since you are getting some power, just not full power
and:
Your machine ran at full power before you changed the board
then:
The power control on L is suspected not to be at a full power level

If the IN is not 5V then the PWM signal on IN is not telling the LPS to run at full power, which points to controller configuration or job settings in the software.

Do you have a milliamp meter for laser current? To help from going down a rabbit hole it would be good to know the current being drawn by the tube at max IN.

7

Correct,

I have a ma meter yes, goes from 0-100% in lightburn to 0-28Ma on meter

8

Sorry I missed that you have a meter.
22ma is full power so as you said, and I missed, you have full power.
This suggests an optical path problem.
Did you change anything there?

9

Initially did not change anything no,

I have however since realigned everything, cleaned the mirrors and lens.

So just changes the board and the software, weird hey?

10

Oh, and aliso installed the ma meter as I did not have it before, just to make sure power is correct, but like you say if it reads > 22ma power is fine?

11

Doesn’t make sense yet!

I would still measure the IN during the job to see if this would give us a clue.

Either something is not asserting full power @IN during the job or there is an optical problem.

Does it engrave the same as before?

12

Let me go and measure the TTL, will get back to you,

Engraving I’m not sure to be honest, didn’t engrave much before, but allso “seems” lighter, but can’t say for sure.

Also, the ma meter is a 50ma, couldn’t find a 30ma one like what is recommended, that’s not somehow limiting power hey?

Thanks!

13

I would not expect the meter to be a problem.
If you want to verify try it without the meter.

14

Ok now I’m even more confused…

Removed G an IN that goes to TTL, measure 1.6v when doing nothing and 2v no matter what power setting.

Also, while I did the tests the laser still fired, without the ttl plugged in, and I could change power settings that reflected on the ma meter. This is with only L connected to the spindle negative??

15

That makes two of us that are confused.

Do you mean that you left IN open? Why?
Left open the voltage you measured make sense?
We want to just measure IN while it is connected.

It sounds like the L signal is also a PWM signal, it should only be an enable not a PWM signal. That means it is asserted when the job starts but does not control the power. This has to be set up properly in config.

I suspect you have 2 PWM signals and that is why power is weird.

Although what you have can work, I never recommend setting up a controller like this.
I normally suggest that:

  • A pot is installed on IN to manually set power limits
  • The PWM signal is connected to L

Try this:

  • Disconnect IN and connect it to 5V.
  • Leave L connected as it is.
  • Run the job and see if it operates properly at full power.
1 Like
16

So just to be sure, can you maybe draw me a pic so we on the same page? When you have time

This is my PSU and DLC32 v2

DLC
DLC1205×815 805 KB

PSU
PSU888×487 92.7 KB

17

The PWM frequency can also effect cutting and engraving. What do you have your PWM frequency set to?

18

Don’t know, where do I set this?

19

Your settings are in the config.txt file.

Please complete and answer these by the assigned #:

  1. Did you check/modify your configuration to match this new setup?
  2. What firmware are you running on the board?
  3. What control panel were you using before this upgrade?
  4. Please download your config file.

I modified (blue traces) your drawing to show:

  • The connection from the controller to the IN pin removed
  • A wire shorting 5v and the IN pin

Note: P should be grounded. This confuses me more because without this ground is should not be firing the laser at all.
5. Is P really left open?

DLCtoK4_Modified
DLCtoK4_Modified659×694 171 KB

20

This wiring is in question… There is no ground on the spindle connection (J7). The PWM output on J18 also drives Q1.

image
image941×212 14.5 KB

Notice on the left is a level translator… the pwm should be 0 → 5V

Maybe I’m lost … along with Don :face_with_spiral_eyes:

:smile_cat: