| 摘要 |
PURPOSE:To make it possible to keep the contents of a RAM immediately before power failure intactly when the power source of an instrument is stopped and to obtain an electronic measuring instrument characterized by excellent maintainability, by inputting data, which are stored in the RAM, into a P-ROM during the power failure period. CONSTITUTION:The regions of variable parameter, computation data and the like, which are stored in a RAM 7 in an operating circuit EN, are assigned in the memory space of a P-ROM 8. For example, when the power source of an instrument is stopped, a voltage VCC, which can drive the circuit EN, is supplied to the circuit EN only by a specified time from a power source holding circuit 2. When the circuit EN receives a detected power failure output signal from a power failure detecting circuit 3, the operation, which has been executed to that time, is stopped, and the contents of the ROM 8 are erased. After the erase, the circuit EN sequentially write variable parameters and the like, which are stored in the RAM 7, into the P-ROM 7. After the writing, the operation is stopped. The data are kept at least during the time from the stop of the power source of the instrument to the stop of the operation. Since the data such as the variable parameters and the data of the computation values are stored in the ROM 8, the data are not lost during the power failure period. |
