Ruida Power Maximum Setting and Lightburn

I have set my min and max power on my controller to 1% and 30% respectively. I have a 50W laser with a limit of 19mA. Setting at 30% keeps the laser from going over my limit.

My question is this. Is the scale i use in LB when creating Cut and Engrave tests relative to the 1-30% power i have set on my controller? For example, when setting 50% power in LB, will it 15% of my overall range?(1-30%)

I hope i have explained this clearly enough.


No. When setting min / max power level on the controller’s configuration, you are establishing an overriding floor / ceiling of power. You need to calibrate your PSU properly:

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How would this be done on a DIY build? My tube is
Cloudray CR50 Max 19mA Rated power 50W, Max Power 70W.
PS is a 60W reaching output as high as 24.9mA

Thannks Jeff

@Stroonzo is the general procedure. The parts don’t know it’s a diy. :slight_smile:

Again, it depends on what you are doing and how fast of a response you require from the power supply. Most are <= 1ms to reach 90% current specifications. Seems to be one place they cut corners, as a user it’s hard to tell if it passed or failed the specification. Especially a new user…

How long is your tube? Mine is 880mm, about 45 watts… and measures about that.



In the post I linked, you will find three additional linked posts that detail the process on how to calibrate your laser PSU.

Strange, I did turn my screw while testing output, but did not seem to make any difference. When i asked vendor, they said screw non-adjustable.

I want to try to add a Min & Max limit to LightBurn itself, in the device settings, and then have everything you send be scaled based on that. It would make it much easier to use the same files on multiple lasers with slightly different power supplies, tube age, etc.


I recently calibrated a Laser PSU for a friend and I was really surprised by the number of turns I had to make on the trim pot to lower the scale.

If by vendor you mean Vevor, I wouldn’t put too much confidence in their answer. That is a ZYE oem or a ZYE clone PSU. If there is a tiny trim pot screw inside of there through this hole:

then it is adjustable.

You also want to be sure you’re ONLY inserting a 100% plastic jewelers screw driver (completely non-conductive) in there if you are adjusting this live. Very dangerous voltages lurk in that PSU waiting to shake your hand and greet you… farewell.

That would be very helpful.

Thanks for the additional info, i will give another try.

The two I looked at were 20 turn pots. Very possible they set these very high to prevent getting returns.
If you sizzle your tube… well it’s your tube and power supply now.

Do you remember, was lowering the current based on Chinese direction or Imperial?


I will print out a plastic screwdriver with my 3D printer.
That should be safe, right?

Probably, but it depends on the plastic. Inside that box could be 30Kv most plastics have the dielectric value available if you hunt for it. I’d probably try and find one that you can spin, which most of them are metal.

Found these, hard to tell the tip type, but they appear to be flat.

Most people that get across small hv supplies only do it once, not because it kills them but it’s not a pleasant experience and they use more care next time. Of course with the right combination there is always the chance of death, even with the mains supply.

Take care
Good luck.


Or just use a wooden dowel that you file down a wedge on:


I use a standard jeweler’s screw driver, a careful hand, and a leather glove when I do them. I don’t trust many of these laser machine components (especially these HV PSUs) coming out of china.

Why the leather glove? Not for electrical insulation I hope :frowning:

I’ve fried a couple of boards ‘assuming’ the Chinese did something in a sensible way. I won’t do that again.


I should clarify, I say leather but in reality I grab a welding glove (usually a TIG glove because they leave more dexterity).

Just ordered a set ,thanks Jack!

how about just turn the thing off, turn a few turns, then turn back on.

My machine even has a separate switch just for cutting power to the laser PSU. I agree, this is the easiest alternative as long as “turn the thing off” is disconnecting the line voltage as well (and not just logically shutting off the PSU).