Meanwell 3-in-1 dimming w/Arduino?

Hello- I am making an LED dimmer for a Meanwell HLG-240H-42B led power supply, using the 3-in-1 dimming capability of this driver. It is basically a 1-10V / 0.1mA connection on the driver, which seems to be a standard dimming approach. The dimming part is easy using a B100K potentiometer. HOWEVER: I want to display this dimming amount on an LCD screen as 0-100%. I was able to do a test using a breadboard and the potentiometer connected to my Arduino’s 5V output. Reading/writing the pot values was fine. But as soon as I connected the potentiometer to the Meanwell’s 1-10V dimming wires, I could no longer read or write the correct values. The potentiometer values I was reading were erratic and all over the place, and writing the value to the lcd screen just produced an illegible scramble of characters on the screen.

Does anyone know what the problem is, and how to fix it? I was assuming that since the potentiometer was connected to more than 5V, this was out of range for the Arduino to read (?). Is there a solution out there for me?


I was assuming that since the potentiometer was connected to more than 5V, this was out of range for the Arduino to read (?).

you must not connect voltages greater than the chip’s power rail on most devices.

Your question leaves a lot of things unanswered.

You need to post a schematic ( not Fritzing physical layout diagram ) and your code as a minimum. As well as a link to this 3 in one dimmer unit.

Those drivers have a buildin 10volt supply, which is connected to the control pin with a pull up resistor.
All you need is to switch the driver’s +/- control inputs with the transistor of an opto coupler.
No extra supply, no extra parts.

Then PMW the opto LED with the Arduino (which has the dim control pot and display).

After a little re-wiring, it seems to be working. I have the 100K pot wired to both the Arduino 5V & ground inputs, as well as to the Meanwell’s 1-10V Dim+/Dim- wires. The analogue pot is still returning quite “shaky” values however - would a digital potentiometer return smoother values?

If you want to tap the control voltage of hat 100k pot, then you should use a voltage divider with very high value resistors.
I would suggest 2.2Megohm from DIM+ to analogue input, and 220k from analogue input to ground.
With DIM- connected to Arduino ground. And analogue reference set to 1.1volt in setup().
See if/how much that influences the existing dim pot, and see what analogue values you're getting.
Edit: Also add a 100n cap from analogue input to ground.

I still prefer the solution in post#1 (the pot connected to the Arduiino).