A method for monitoring machining in an electroerosion assembly having a power supply and an electrode arranged across a gap from a workpiece, includes measuring a voltage at a point in a voltage waveform after a time delay td of one half of a pulse width of the voltage waveform. The measurements are repeated for multiple pulses of the voltage waveform to obtain multiple voltages, each of the voltages corresponding to a point in respective pulses. The voltages are averaged to obtain an average voltage, which is compared with at least one threshold voltage, to determine whether the machining is in control. A control signal is generated if the comparison indicates that the process is not in control, the control signal being configured to regulate an operating parameter of the power supply, and the control signal is supplied to the power supply, if generated.