Hello raschemmel,
thanks for your input. I just calculated that I will have 163 steps for the fan control (0,7 to 1,5V), and 83 steps for the current control (4.0 to 4.4V).
Do you think that this resolution is not enough? Things are rather noisy in such a power supply anyhow. 60mV ripple is not unheard of. This is the output, so not strictly relating to the CS voltage, but as this is measured against the output negative, I would gess that the resolution of 0,0049V and the ripple of 0,06V mean that the readings will already be affected by noise, and increased resolution will not improve things.
(Mental note: Connect Pin 1 to ground with a capacitor, and put resistor in cable from CS Pin).
Regards,
Julez