JPS54103665A - Pulse signal counter circuit - Google Patents

Abstract

PURPOSE:To avoid the overlap of the counting action and the resetting action of the counter and thus to prevent the count error by using the comparator to detect the pulse signal and then locking the operation of the comparator at the resetting time of the counter. CONSTITUTION:The signal supplied from machine contact 1 is converted to the voltage level through contact-voltage converter circuit 2 to be used as the input of comparator 25. Reference voltage 24 is set at one side of comparator 25. And if the input voltage is higher than voltage 24, logic 1 is delivered 28; while logic O is delivered 28 when the input voltage is lower than voltage 24. Thus, the counting is carried out through counter 4 at the time point of 1-0. When address signal 5 is received from the computer with the input signal turned on, the output of AND gate 7 features logic 1 to lock the operation of comparator 25. Accordingly, no counting is carried out under the reading action of the computer. After the reading action, comparator 25 operates based on the input signal when the address signal 5 exists. In other words, comparator 25 is locked for its operation at the resetting time of the counter and after end of the reading action, thus preventing the overlap of the counting action and the resetting action of the counter.