PROGRAMMABLE CONTROLLER

PURPOSE:To start a programmable controller accurately with use of many timers of short time bases by counting the time base reaching frequencies to produce the elapsed time information data and integrating this time information with the present time value data of the timer to always renew this time value data. CONSTITUTION:The cycle of the fixed cycle signal produced from a fixed cycle signal generator 22 is coincident with the time base of a timer. The contents of a register provided in a CPU21 are saved a sequence program processing mode corresponding to the signal input and stored temporarily to another memory. The count value of the input frequencies of the fixed cycle signals is added by 1, and 1 is added to the storage contents of a count memory 24. The storage contents of the memory 24 thus renewed are used as the elapsed time information in a single scan. The storage contents of a register within a CPU1 are reset to a state set before discontinuation of processing to complete a series of processes. For the post-processing of the elapsed time information, the interruption is inhibited for the input of the fixed cycle signal. Then the elapsed time information data in a single cycle signal. Then the elapsed time information data in a single scan is transferred to an elapsed time information memory 25, and said inhibition of interruption is released for the next measurement of the elapsed time.