Can PAV series turn on the output when the POWER switch is turned on?

Yes, but you need to set the start mode to the auto start mode.
The factory default is the safe start mode.
How to set the auto start mode:
a) Hold down the OUTPUT key.
The voltmeter alternates showing “SAFE” and “AUtO” at 3-second intervals.
b) Release the OUTPUT key when “AUtO” appears.
The auto start mode can save the output on/off setting until PAV are powered on again. Therefore, if PAV is powered off while the output is on, the output will be automatically turned on at the next power-on.
For the details, read the user’s manual – chapter of Basic Operation – Output Operation – Safe start and auto start.