| 摘要 |
PURPOSE:To accurately detect rotation of a rotary object, by a method wherein, in a water meter, an output of a magnetic resistance element is digitally processed to perform a detection of a pulse. CONSTITUTION:A permanent magnet 2 turns with the rotation of a vane 1, and a magnetic field direction of the magnet 2 is detected by a magnetic field direction of the vane 1 is converted into a pulse, the pulse is converted (6) into an amount of water used to display it in a display unit 7. Then, if, in a circuit 11, a clock CLK1 is applied to a FF21, an up down counter 23 counts a CLK2 corresponding to the output of the element 4. Then, the element 4 generates an output at time constants RaC and RbC corresponding to closing of terminals 4a and 4b, and the counter 23 performs an up down count. Each counting value is latched by a CLK3 right before the CLK1 enters, circuits 26-0-26-7 send a preset signal to the counter 23 based on the latch output, and a data, previously determined based on a hysteresis width, is pressed in the counter 23. |
