In real life, calibration is done via the onboard potentiometer. In Proteus, you calibrate by adjusting model parameters.

Ultimately, the best approach depends on your goal. If you need to verify the precise interaction between the sensor's analog front end and your code, building a detailed equivalent circuit is the way to go. If you're simply testing high-level firmware, a generic signal source will save you time and effort. Both methods will successfully bridge the gap and allow you to leverage the power of Proteus simulation for your AC voltage sensing projects.