| 摘要 |
PURPOSE:To perform an accurate counting by providig a counting check part, which checks the counted value at intervals of a prescribed period to correct the counted value if it is not within a prescribed count range, to eliminate the noise when the noise is mixed with an input pulse. CONSTITUTION:A control program of a microcomputer 7 uses the count output to control turn-on/off of an object 9 to be controlled. A counting check part 19 compares input numbers Tmax and Tmin of pulses, which are counted during a maximum and a minimum of the execution time of a main program part 17, with a number T of pulses which are inputted during the execution of a main program, and the value T is used for counting as it is in case ofTmin<T<Tmax, but an average value T=(Tmin+Tmax)/2 is set in the other cases and is used for counting. Thus, the count error for superposition of the noise onto the pulse input is reduced to attain a timer without error. |
