App-35
IM WT310E-01EN
Appendix
App
The voltage signal that is applied to the voltage A/D converter and current A/D converter is converted
todigitalvaluesatanintervalofapproximately10μs.Thesedigitalvaluesareisolatedbytheisolator
and passed to the FPGA. In the FPGA, the measured values are derived based on the digital values.
ThemeasuredvaluesarethentransmittedtotheCPU.Variouscomputedvaluesaredeterminedfrom
the measured values by the CPU. The measured values and computed values are displayed and
transmitted (as D/A and communication output) as measurement functions of normal measurement.
The harmonic measurement functions (option) are derived in the following manner. The voltage signal
sent to the A/D converter is converted to digital values at a sampling frequency that is determined by
the PLL source signal. The CPU derives the measured value of each harmonic measurement item by
performing an FFT on the converted digital values.
Appendix 7 Block Diagram