Depending on the model, you can select one or more of the following closed-loop modes:

• V² control – compensates for mains voltage fluctuations, keeping the square of the output voltage (and thus heater power) constant.
• I² control – maintains constant squared load current, useful when load resistance drifts.
• P control (true power control) – measures both voltage and current and calculates real power, keeping it constant independent of line or load variations.
• Open-loop voltage control – output follows the setpoint linearly as a percentage of full voltage.