For the 0-15V output on the expansion port (not the main power output):
For Ace, the 0-15V is a voltage regulator with adjustable voltage that can supply up to 600mA. The regulator can be turned on and off in the UI by clicking the arrow next to your Ace and then choose wanted voltage. 0V means that the regulator is turned off.
Can the output power be monitored/recorded in the GUI? Instead of using the main output terminals??
No, 0-15V as an output can not be monitored directly.
What you can do, is connect 0-15V, via an external sense resistor, to the consumer and back to GND.
Then connect the sense resistor high side to ADC+ and low side to ADC- and enable ADC voltage, current and power channel. Voltage is measured at ADC+ pin and referred to expansion port ground.
The expansion port is floating so it is important to get the GND right, to get the correct voltage and power reading.