Power meter shows EE when laser is operating

[lauckstreet]

Today I ran my first test on my 80 watt laser. I simply drew a box in LaserCAD that was 20mm x 10mm, downloaded the file to the controller and ran the file. I set the power in LaserCAD to 50% max and 40% min. The box drawing was set to CUT, not engrave. When the laser ran, it basically etched the box in 1/4" aspen, a very soft wood. I watched the power meter as the laser was running and it went to 19 and then it displayed EE.

I did not run any more test because I'm not sure what the EE displayed in the power meter means. The box that was etched was correct in dimension but it did not burn very deep so I know I'll need to apply more power but do not want to try that until someone can tell me what the EE means that was displayed on the amp meter. My guess is it's not good, like exceeds range.

The test of this box took only a few seconds. Perhaps I have the meter wired incorrectly. Any help would be greatly appreciated.

Thanks,

Bob Hunt

[lauckstreet]

So nobody knows anything about this problem? I'm not surprised.

Bob

[NickWL]

OK - rather than leave you feeling unwanted and unloved I'm going to have a guess (and that's all it is):
The power meter has suffered some kid of trauma and is showing 'Error' to the best of its ability. A new meter costs very little so replace it, fire up the laser on minimal power and see what happens.
Not incredibly useful info, but who knows...

[lauckstreet]

I ran the same test again this morning but slowed the cut down to 5mm per second. The meter starts by showing 9.0 but but in a few seconds goes to -E.E. The cut is not deep at all, less than 1mm deep and that's at 50% power with an 80 watt reci tube. Seems like it should be a lot deeper at 50% power.

I'm not so sure it's the meter. I've read a lot of postings in the forum concerning laser tube problems and such and I wonder if it's the power supply. I've triple checked my wiring and I'm pretty sure the wiring is correct. The movements I know are correct and only thing left is the wiring of the meter with the 5v isolated power supply part and the meter itself.

Any help, comments, suggestions would be greatly appreciated. As it stands right now, I'm afraid to run the laser any more for fear that the -E.E showing in the power meter is a sign of a real serious problem. Given the fact that the cut is more like an etching than a cut, I really think there is a serious problem.

Bob

[lauckstreet]

Ok, here are two photos, one showing the laser power supply and the other showing the meter wiring. I'm sure they're wired correctly but thought posting the photos would at least help confirm that.

Basically I have an outlet/switch mounted to a front panel where AC power comes in. The power coming in is connected to a terminal strip where it is distributed (in parallel) to several circuits which include the laser power supply, the 24v power supply and a 12v power supply used to supply power to an exhaust fan and a few other devices.

Then there's an upper control panel which has the DSP control panel mounted to it, the power meter and some other meters and buttons controlled by an arduino uno. Those circuits only get turned on when the buttons are pressed which turns on the air blower, air exhaust fan and a counter to keep track of the number of hours on the laser.

I'm really at a loss as to why the laser isn't cutting very deep and why the meter starts to display the current and then goes to -E.E. Anyone have any ideas, comments, suggestions?

Bob

[lauckstreet]

I was just browsing the page for the meter on Lightobject's web store and there's a comment in the review section that says the meter isn't wired in series but is wired in parallel. This would mean that I still need to connect a wire from the - terminal of the power supply straight to cathode of the laser so that power flows directly from the power supply to the cathode AND flows through the meter. Is that correct? The wiring diagram doesn't show that. It simply shows a series connection and nothing else.

Bob

[lauckstreet]

Ok, I wired the meter in parallel and now the meter reads -1.7 with my drawing set to 70% power. When the laser begins cutting, the meter starts at -1.2 for about 1 second, then goes to -1.7 and stays steady at -1.7 through the entire cut.

Even at 70% power, the cut isn't but a few thousands of an inch deep, probably no more than .2 or .3mm. Also, when I first tried this test originally, I used the red dot laser to adjust focus which put the distance from the bottom of the lens tube about 1" above the wood. I thought perhaps the wood needed to be closer to the lens tube so I put a piece of 1/4" wood under the piece being cut thus raising it up and putting it closer.

This last test didn't go any deeper than the first test. The cut is a little wider but still not very deep at all.

Bob

[NickWL]

NOOOOOOO!!!!!
Meter is wired in SERIES, and (on mine, at least) the GREEN wire goes to the blue of the PSU.

[lauckstreet]

NOOOOOOO!!!!!
Meter is wired in SERIES, and (on mine, at least) the GREEN wire goes to the blue of the PSU.

That's not what one reviewer said about the meter. I connected a second wire directly from the - terminal on the laser power supply to the cathode of the laser and ran the test again. That seemed to get rid of the -E.E reading. Also, when wired in series, that means the meter's resistance is impeding full power. In parallel, the laser receives full power as does the meter.

The negative reading is what confuses me. Your remark that the green wire goes to the blue on the PSU makes no sense to me. There is no "blue" wire on my laser power supply, only a terminal Also, this thread : viewtopic.php?f=14&t=187 has a photo that states that the blue wire goes to negative and the green goes to postive. Based on the diagram provided to me, that shows the - (negative) to be the terminal on the laser power supply, that's exactly how I wired me.

I wish someone could draw and post a more clear diagram of how the wires for the meter are connected to power, to the laser and so forth.

Bob

[lauckstreet]

Ok, I reversed the blue and green wires. Now I have the green wire on the meter connected to the negative terminal on the power supply. I have the blue wire connected to the cathode of the laser. The same test was ran, 70% power. The cut is still very thin, only a few thousands of an inch deep. The meter reads positive now but is only showing 1.7 when at that power, it should show around 22 to 24 ma.

So there's still a problem and I'm still wondering if the laser power supply is bad or if I have some setting incorrect. Any help, comments or suggestions would be appreciated.

Bob

[Tech_Marco]

Bob

Follow the diagram I sent you:

viewtopic.php?f=16&t=1759

You may want to reverse the Green & Blue wires as the they (supplies) sometimes swap the two wires
I mentioned many times not to use color code but look at the legend mark printed on the PCB

When laser is not firing and seeing "-" is normal as i5 is in open circuit

NEVER connect the current meter in PARALLEL to the load. You will blow the meter badly (kill it)

Now your current meter beciming a "voltage" as the internal shut should be cooked and well done



Marco

[lauckstreet]

I just spent several hours aligning mirrors with targets taped over the round openings. This are pretty well aligned now. Reversing the wires did get rid of the negative reading and it's wired in series and is now reading 24.5 on the meter at 60% power. I tried 70% power and it went to 28.0 on the meter which is the max for this laser.

I was able to cut a 1/4" piece of plywood at 60% by slowing the movement down and power remained around 24 ma, so I think I'm in business now. I'll continue to run test cuts and get more familiar with what I can cut and at what power and speed.

Thanks,

Bob