What are the 2 sources?
You mean PWM from board and also the remote test/potentiometer?
Yepā¦
Thatās been bothering me for a while.
I assume that means that the IN on the LPS is wired in series with the remote pot. But that doesnāt explain how it would work with the remote disconnected. So must be bypassed when the remote is not connected.
Iād be curious to see that confirmed.
It was even worseā¦ wrong controllerā¦ 
I donāt know, although I follow your logic here.
The K40 have the IN voltage set with a pot or variable supplyā¦ pots are cheap.
Then they toggle the laser on/off with the L/H pin of the lpsā¦
I would think it odd they changed that.
Still no answer where/what L is connected. It takes both of these to control the lps.
Iāve seen these that have a switch on the lps and you select the remote or the IN terminalā¦ Some users have stated that just removing the remote worksā¦
I doubt itās in series, more than likely just a dc control for the IN terminalā¦
Guess weāll never knowā¦
In another Topic I believe L was bridged to ground. Iād assume thatās the case here.
I donāt see how it would serve to attenuate the IN voltages if it wasnāt in series is how I was thinking about it. I donāt think thereās signal processing going on so assume itās just an analog pot. But just speculating.
If this was the case, it would lase with any voltage on the IN terminal.
This is the issue I have with these. They way many think this is working isnāt support by what we know of itās wiring. I donāt think it is attenuating the IN voltages.
Iām still convinced itās a cheap way to wire up a pot on theseā¦ and thatās it, not some great design change to enhance itās user base, just lower cost for manufacturing.
Ruida and other dsp controllers handle the lps correctlyā¦ most of the K40 types handle the lps like itās a diode.
From what I recall that was indeed the behavior.
Maybe I missed it. How is this in contrast to how itās wired?
Also, how would the remote be used to scale overall power without attenuating the voltage?
I think this could still be the case. Iām not suggesting something fancy.
I believe this is only true for GRBL based lasers. I suspect itās a cheaper way of doing it than adding the circuitry for separate laser on and the ability to pull to ground. None of the commodity GRBL laser boards have that out of the box so require it.
The M2 Nano boards that K40s used to ship with and I believe all the Smoothieware boards work basically like what you expect, at least from what I recall. With the exception of use of pot for IN vs PWM control. Oddly, I believe Cohesion board does PWM through L.
If the pwm is going to the L (or H) input, then the laser is being enabled by pwm, not controlling tube current, which is the IN terminal.
In effect removing actual tube current control from software and delegating it to the manual pot. Setup this way, the tube lases at the set value every time the pwm enables or turns on the laserā¦
In effect itās lasing at 100% power any time it lases.
Power isnāt actual power, but power/time, just like a sslā¦
One of the reasons I attribute to their relatively short tube life.
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Iām not much of an electronics guy, so most of this was a foreign language to me. Nevertheless, it was interesting.
Ultimately, I just wanted thank all of you for āputting it out thereā. Iām sure it will be invaluable to somebody in the future.
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We sometimes go off on technical tangents as we are all learning from the interaction. We try to limit this, but many of us are just naturally curious ā¦ canāt change my spots
Have funā¦ thatās the main idea.
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