Laser not working after upgrade (settings)

It was out with the old and in with the new. Now that everything is back together, I am working through the rudia configuration. Can you please help me transfer my original params to the new controller?

If you have two identical controllers, then you can save the settings from the old one and restore them into the new one.

If you have two different controllers, then it’s a manual process, because the internal structure of the files will be different.

The least awful way would be to connect the old controller to the power supply and network (or USB), use LightBurn to display its Machine Settings, then make screen shots of all the values. Disconnect the old controller, fire up the new one, and start typing with the screen shots as references.

Even with identical controllers, it’d be a Good Idea™ to verify the new settings by comparing them with the old ones.

Thanks for the info and response. Sadly I am moving from different types of controllers and the previous controller is not light burn compatible. I will see if there are any machine settings in the previous software that can shed some light on the laser settings. I know my control signal needs to be low, but past that I am not sure how or what the other ruidia settings should be. Can I damage my tube with bad settings?


Somewhere these setting are probably on the old controller. If I remember correctly it’s a decade old so it could have had both hard/software developed as a package. Even back then they knew better than to hard code things like stepper motor information in these. Doesn’t mean they didn’t.

The trick will be finding something, software wise, that will talk to it and understanding what you are getting out.

Not really … The fact is that there is no use to have the lps operational until everything else is functional. I’d highly suggest you take it out of circuit, at least the mains power until you are ready to actually try using it as a laser. Having it able to lase in these circumstances is just not worth it.

My machine has a mains switch so I can run with the laser disabled. It’s also got a connector so I can easily just unplug it to disable it.

Hopefully you have an analog mA meter to monitor your current draw so it’s not over driven.

Have fun…


Small update. I moved my switch to turn on and off for the water cooler from the IN1 to the relay in my control box. I also shorted the water protection on the laser power supply and moved the alarm wires over to the ruida.

Now it is time for the laser itself, I have a 100w co2 glass tube. The manual says the L-AN1 is preferred over the LPWM1 pin. Do any of you have experience and or advise for using the L-AN1 pin? Would it be terrible to use the PWM pin?

I don’t know where you read that there is a preference… but in reality it doesn’t matter.

When the signal goes through the IN input of the lps it goes through a simple filter and becomes more of a voltage controller oscillator setup.

These machines are designed to be compatible with older/new equipment. Analog voltage control was the standard until micro controllers showed up and with a computer it’s easy to generate a pwm… whereas most analog outputs require additional hardware.

Mine and most of them I see use the pwm signal. I prefer the pwm signal, but in the end it matters not.

I’m used to digital interfaces, but it’s up to you… the beauty of diy…


I’ll move my laser wire over to the PWM pin. Form the manual for the L-AN1 pin it says: “The analog signals for Laser Power. If Glass Tube is used, this pin is recommended to control the power of the Laser.”

I believe you…

A couple of the new Ruida I looked at do not have an analog output… only pwm…

It’s changing…

A Trocen AWC708 has no analog output…

Ruida RDC6432 manual shows it with the pwm, not the analog output.

Good luck


We are back!
@jkwilborn you were right, the laser works on either pin. Turns out that the previous controller had a low signal for the laser. I switched from low to high as a sanity check and boom. My machine is back online (less, axis tuning and focus distance). Off to setup the camera…

So does the Ruida, so what did you change?

Which signal, specifically, are you referring?

The Ruida sends a continuous pwm signal as soon as the machine starts executing a layer. The laser is enabled or fired via the L-On1 output from the Ruida… This is active low and is usually connected to the L input of the lps.

So you have me curious…


In my original images you can see the signal low setting. On the new controller, you can see the new high setting. That’s all the info I have

Where have you connected the L-On1 output of the Ruida to the lps? It usually goes to the L input. The H input is the inverted L input…

Nice console… :crazy_face:


Looks like I was referencing on older manual. The L-AN1 is L-On1 in the version I have. Maybe I will move it back to the PWM port. That said, changing from signal low to high is what made the laser start firing again.

Success is good however I’m wondering how it’s wired up…

You mis-read the document or you will have to show me :face_with_spiral_eyes:

LPWM and L-AN can be interchanged.

From the Ruida to the lps

L-On → L
P → ground

Is this how it’s wired?

Something isn’t right…


It looks like I have all the ports…
L-AN1 → IN(?)
WP1 → To chiller
LPWM1 → Open
L-On1 → Was TH on the laser box, now I have it on TL.

Changed the control signal back to low and it is working.

Depending on how the controller generates the analog output, it may have a lower bandwidth than the PWM output, which translates into slower response for small features. Unless you know for sure the controller uses an actual DAC with a proper reconstruction filter, use the PWM output.

I blathered on about that a while ago:

Definitely more than you really want to know … :grin:

Great that it’s wired and working…

There was no need to move it to the L input, you inverted it and applied it to an input that is designed to be inverted… So you were good, I was just wanting to ensure you machine is operating properly…

I assume the previous controller used the H input?

Good luck and take care


@ednisley Those are nice write-ups! I am down for all the knowledge you are willing to share. To a point though, I do want to do some actual laser work as well :wink: Since I am not (or at least not yet) replacing my laser control box, I am going to move back to the PWM signal. Only because that is how it was wired up before.

@jkwilborn The laser power box has a TH (high) and a TL (low). In order to keep my settings in the Ruida standard (low), I just moved the connection. My original controller may have been set up a little backward. :man_shrugging:

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