Cannot get laser to fire with vevor 50 psu and mks-dlc32

[benhutje (Ben)]

Hello everyone,

It seems that I need some help.

I have build my own laser machine with a MKS-DLC32 board to control it. Moving it works absolutely fine but connecting it to the laser power supply seems to be a bit harder than expected.
I cannot seem to find the right pins to connect the machine to. I have bought the powersupply of Aliexpress (the 50W version).
https://nl.aliexpress.com/item/1005005730279570.html

The documentation that I recieved with the supply seems to have a different pin configuration than it says in one of the pictures and on the vevor website.

documentation says
L- FG AC AC G P L G IN 5V 24V G 5V L
website says
L- FG AC AC H L WP G IN 5V 24V G 5V L

I have measured the pins (the 6 pin connector) and these are their outputs
0 4,2V 4,2V 0 4,6V 5,0V

When I run the board on GRBL-M3 and activate the laser on 20% I get these outputs :
on the spindel output: 2,13V
on the signal and TTL output: 0,25V

I have read through a bunch of similar posts on this forum and have tried a bunch of different solutions all without much result, if someone can help me out that would be greatly appreciated.

[benhutje (Ben)]

@jkwilborn I saw you reacted to most of the forum questions regarding these boards so you might know a thing or two

[jkwilborn (Jack Wilborn)]

@benhutje

documentation says
L- FG AC AC G P L G IN 5V 24V G 5V L
website says
L- FG AC AC H L WP G IN 5V 24V G 5V L

Where did you get these?

Does the lps have the pins identified, like the one in the link?

This is mine, they seem to be the same as your link.

@benhutje

spindel output: 2,13V

You should not be using the spindle output of the DLC32. The PWM is generated by the cpu at 3.3V and is passed through the 7400 series chip that’s used as a voltage translator so the pwm goes to LC-0 at a 5V pwm. This directly drives the pwm coming out of J18.

If you use the spindle- (J7) it’s only grounded when the pwm goes high and enables Q1 to pull the negative pole to ground. The other pin is just the supply voltage.

How is the DLC32 outputs wired to the lps?

I hope you’re not using the 5V output to power the DLC32, most of the times these outputs supply a very low current.

Whose firmware are using?

Make sense?

[benhutje (Ben)]

@jkwilborn

Where did you get these?

The documentation one I got from a piece of paper that was in the package with the power supply:

The other one I found on the vevor website.

Sadly it does not say anything on the laser power supply itself, it does tell me the pin layout of the two outer plugs but not the 6 pin comunication one.

@jkwilborn

Whose firmware are using?

The latest version from the Mks Github

@jkwilborn

I hope you’re not using the 5V output to power the DLC32, most of the times these outputs supply a very low current.

I am running the board on the 24V output of the laser supply

@jkwilborn

How is the DLC32 outputs wired to the lps?

I have tried a bunch of things, but the most common one I tried is:
IO32 (S) to the IN port
GND (TTL) to the G port

[jkwilborn (Jack Wilborn)]

The lps you’re dealing with appears to be a K40 type lps. This is not the same as the link you posted. I’d use the first one as the pin out since it matches the connectors shown in the photo. I think yours is a type 1.

K40 Laser Cutter Power Supply: Pinout, Wiring Diagram, and Vital Facts | K40.se

I had mine setup on my co2… You have to have the P (water protect) of the lps wired to your flow switch or tied to ground, bypass the water flow protection. I would not recommend you bypass this protection… Saved me a couple of times.

I ran L to a console switch to enable the laser, but pulling it low. Then the J18, S (pwm) to the IN terminal.

[benhutje (Ben)]

@jkwilborn

The lps you’re dealing with appears to be a K40 type lps. This is not the same as the link you posted.

In the link you need to select the 50W version then its the same one

But if these pins are what I have as well then I should :

@jkwilborn

You have to have the P (water protect) of the lps wired to your flow switch or tied to ground, bypass the water flow protection.

Connect pin 1 and 2, GND to P+ (will add the waterflow sensor later just to make sure that that is not faulty)

@jkwilborn

Then the J18, S (pwm) to the IN terminal.

So just one cable from the board to the power supply? that does not need a GND or anything?

@jkwilborn

I ran L to a console switch to enable the laser, but pulling it low.

Can you explain this a bit further? How do you pull it low? I connect L to a switch and then to ground again or do I understand that wrong?

Thank you for responding so quickly!

[jkwilborn (Jack Wilborn)]

@benhutje

that does not need a GND or anything

If you want any electronics to be able to use a signal, it needs to be relative to something. So single signal lines require a ground reference. So yes you need to ensure there is a ground across all components.

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Use the pin out for the supply that has the same group types of connectors.

If we exclude mains power, then one lps has a pair of connectors, while the other only has one.