I tested the DAC module. You need to use dac0.writeData (Volt, save = True) in the range from 0 to 2700 to get from 0 to 3.3V. For variable indications to be similar to voltage, they should be divided by 0.00125.

 https://photos.google.com/photo/AF1QipMS4Ws6-kcJZl0RY_76b5v7PmTZ7ptHddbI-hJR

I made a simple temperature regulator. I have attached a DAC module. Everything is fine when I send zero value - the module gives zero. If the value is greater than zero (1-100%) the DAC module gives 3.3 V or 100%. Do you have any description of how the DAC module works?