If applicable. Record values measured before switch S1 is opened. Recorded when the test is carried out using a PV array. Pyranometer should be fast response silicon-type not thermopile-type. The response time of voltage and current transducer shall be suitable for the sampling rate used. The waveform, AC voltage and current shall be measured on all phases. The waveform data shall be recorded from the beginning of the islanding test until the EUT ceases output. The measurement of time shall have an accuracy and resolution of better than 1 ms. When the waveform is recorded, the synchronizing signal of the S1 opening and stopping signal may be simultaneously recorded. If available from the EUT. Signal shall be filtered as necessary to provide fundamental (50 Hz or 60 Hz) frequency value. Fundamental values will ignore incidental harmonics, caused by utility voltage distortion, absorbed by the load and EUT filtering capacitors