Power Settings Won't Adjust

I have set up my 100w red/black chinese laser with a Ruida 6442S-B Controller, and everything is working expect power variance. No matter what I do, the power is the exact same every time I burn.

I have adjusted the minimums and maxes in both the controller and lightburn, but nothing adjusts the power amount.

I have checked many previous forums with no luck for a solution. Any help or advice is appreciated.

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The laser is only on or off? You should be able, from the front panel, to set Maximum and when you press ‘fire’ it will output whatever that max is set to. Mine is usually set to 80%, but when I’m aligning mirrors or something I drop it to 20%. This is a good way to tell how low you can go. Mine doesn’t fire under 9%. I also have the manual set to 15ms when I fire it.

With a target you should be able to tell the difference between 80% and 20%. That would tell you if the Ruida is operating.

Let us know… :slight_smile:

Hey Jack thank you for the response. Unfortunately neither adjusting min/ max on the controller or the software are having an affect of the power of the laser.

Everything time I test with some square patterns they come out looking exactly the same.

Here is a picture of my controller board. Not sure if anything is miss-wired, from what I could tell by researching the issue I think everything is wired correctly.

I’m afraid you misunderstood what I was trying to get you to do. All from the front panel. If you set the max value low (like 10%) then press the ‘pulse’ button to fire the laser it will fire it at whatever you set (like 10%).

Under program control you can override some of these.

Here’s the Ruida manual it’s in ‘Chinglish’ but not too bad. Most of it is the item, it usually says little about how it actually effects your work.

You need to determine if it’s firing continuously or is being pwm correctly.

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By front panel, you are referring to the screen console on the laser correct? Because if so, I am setting my max on there from 20-80 and not seeing any difference.

I apologize if I am misunderstanding.

Don’t worry about opps, we all do it.

You are firing the machine from the front panel also? Should only be a spot.

I believe it’s ‘L-on’ that actually fires the laser. If you have the ability to check that? A scope is always good.

I’m gathering that it lases when it supposed to but just the power is not adjustable. Do you have a ma meter hooked up? Does your lps have an led to show when it’s triggered?

You are correct. It is firing when it is supposed to, it is just not adjusting the power. Which is leading me to believe I need to check the PWM.

I do have a millimeter; however, I must admit I am not very knowledgeable about electrical or testing electrical. To measure the PWM do I measure from the “IN” connection (which runs to the LPWM1 port on the Ruida board) on the LPS?

From there the mA should reflect the percentage correct? Ie. 5A =100% power , 2.5A= 50% power.

Does this sound correct?

Also, the Ruida manual states that for a glass tube it is recommended that you use L-AN1 port at CN5. Should I rewire the connection from “IN” for LPS to L-AN1, or leave it plugged into LPMW1?

Thank you so much for helping me through this. I have learned a lot just by your previous guidance.

To check PWM you really need a scope. A multimeter checks voltage/current/ohms. You really can’t measure it realistically on a multimeter.

If you have a miliamp meter, it’s reading is relative to output power. It is connected to the low side (going to ground or return) of the laser high voltage supply line.

If you have a meter such as this one on my machine. It’s next to the emergency off button on my machine. My power supply also has a digital ma meter. It is relative power, but is the current flow through your tube. Shorter PW, lower current. I try not to run mine over about 21 ma. Most of the engraving is about 4 ma. You cannot judge the output from the power input, generally speaking.

Good question… I’ll have to look at mine… :slight_smile:

Could you have possibly crossed up LPWM1 and L-On1? That would cause this I believe.

Here are the connections to the laser power supply. At least in my machine.

From what I can see the only control lines go to L and IN. From the Ruida CN5, L-On1 goes to the L pin of the laser supply. LPW1 goes to the IN of the supply.

It looks to me that the L-On1 enables the laser and the IN line is the PWM input.

Double check those…:slight_smile:

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So unfortunately I don’t have a miliamp meter.

I did recheck the wires, and it appears they are connected correctly. With L going to L-ON and IN going to LPWM.

I also did use a multimeter on the PWM connector and it’s voltage readings are linear to the power settings, i.e. 50% power = 2.5V out of 5v.

However, the odd thing is the laser is still only firing at one constant power disregarding the different powers. I even put the max power at 1% and it still fires at the same power, yet the PWM connector reading is linear to the voltage at .06V.

you need to set the correct values ​​on the panel. put at least 1%. maximum 99%.
at least 20% like you, that’s a lot. My laser cuts 20% through 4mm plywood. Therefore, you do not see the difference. You say in LightBurn to cut with 1% power, but in fact your power is 20%.

Am I missing another way to set the max/min? I have my minimum already set at 1% and max at 99% on my Ruida controller panel. Through lightbulb I am having different test burns on different layers/colors at a variety of power levels within that 1-99% power range, yet there is no difference in the burns.

Is there another setting I am missing?

At this point the only thing I can think of is maybe the factory settings are incorrect or wrong, and are overriding my settings.


What is the state of L-On1? The only reason I ask is that if the main enable is just turning it on, then you have a bad supply. It sounds like the PWM measurement is reasonable. Since the PWM is changing it only leaves the L-On1 line turning the laser on and off. The power supply is ignoring the PWM signal.

My guess is that if you remove the PWM line, it will still fire full power.

Good luck :slight_smile:

Are you still having the issue, or did you figure it out? When I’m in “Line” mode, it sounds like my laser is doing the same thing, the power jumps right up regardless of my settings. Is your laser varying output in engrave mode, but not line mode?

Mark C.

I have the same issue, did you solve it?

Hi, no, I hope to hear back from Chris on if it is line mode only, but mine is not resolved, still trying to figure it out:
Same Settings Producing Different Results: Draw 2mA in Fill Mode, Drawing 10mA in Line Mode - LightBurn Software - LightBurn Software Forum

I was having issues getting my power turned down enough to not burn through and after trying everything went to tools/machine settings, and my minimum in the machine settings had somehow been changed to 30% after changing it back to 10% I was able to control everything again.

Great, I think we were miscommunicating. Glad you have it under control.

Take care :slight_smile:

I will take a look again in Machine Settings, thanks!

Make sure that lb has downloaded the settings from the machine and then be sure to load any changes back to the machine