| 摘要 |
PROBLEM TO BE SOLVED: To calculate a flow rate integrated value with high accuracy even if power supply frequency is changed.SOLUTION: A synchronizing signal extracting circuit 18 extracts power synchronization signal T synchronized with a period of external AC power AC from the external AC power AC. A control circuit 14 counts a sampling period Ts based on the power synchronization signal T. A flow rate integrated value Fe is calculated by sequentially-integrating a value obtained by multiplying the counted result Ts by a flow rate measurement value (instantaneous flow rate) Fs. |
