hi, @berton
I'm also working on the same thing using ESP as the controller, trying to control FL5150. Firstly I made the dimming circuit using the adjustable resistors and I succeed with both dimming types(LE and TE). Now I'm trying to add microcontroller part to it.
How can you place 4 optocouplers across series R network to produce DAC values? Is it to get isolation between AC ground and Digital ground?