An arrangement for controlling a plasma processing system is provided. The arrangement includes an RF sensing mechanism for obtaining an RF voltage signal. The arrangement also includes a high impedance arrangement coupled to the RF sensing mechanism to facilitate acquisition of the signal while reducing perturbation of RF power driving a plasma in the plasma processing system. The arrangement further includes a signal processing arrangement configured for receiving the signal, processing the signal in a digital domain to obtain peak voltage information for a fundamental frequency and a broadband frequency of the signal, deriving wafer bias information from the peak voltage information, and applying signal to a transfer function to obtain a transfer function output. The arrangement moreover includes an ESC power supply subsystem configured to receive the transfer function output as a feedback signal to control the plasma processing system.