So after few years this project reached its final stage. The goals have not been met. It is not precise at all and it is not so universal as it could. It was killed by its own complexity and also the concept of supply units was flawed. The unit consists from one control board with MCU which handles IO on the front panel (USB communication, stepper motor output, 4 digital outputs, 2x analog output, load cell input, 2x analog inputs and 8x digital inputs) and communicates with two separate isolated power supply units with MCU which could be internally connected in series for 50 V, 2 A output or in parallel for 25 V, 4 A output. Output voltage setting accuracy +-100 mV, current limit setting accuracy +-100 mA.

So it works as really over engineered but low cost power supply and I do not plan to update it anymore. Also it is possible to control and read all its inputs and outputs via USB so it provides some remote control, but I have never used these features. Possibly 35 % of desired features have been implemented. Eventhough it is overall fail it has been a great life lesson and experience.