TIMER INSTRUCTION PROCESSING SYSTEM AND APPLICATION INSTRUCTION PROCESSING SYSTEM FOR PROGRAMMABLE CONTROLLER

摘要

PURPOSE:To execute a timer operation with high accuracy and at high speed by providing a timer elapsed value area for the timer operation, a timer auxiliary elapsed value area for a high accuracy operation and an elapsed time area for deciding an operational condition and setting a unit of an elapsed value to the relation of 2 X a unit elapsed time. CONSTITUTION:At the time of a timer instruction processing, when a subtracting operation is decided by a CPU unit, a unit elapsed value is set to the relation of 2 X a unit elapsed time, the fraction of the previous elapsed time is read out of a timer auxiliary elapsed value area and added to an elapsed time read out of an elapsed time area before a timer operation, AND of the added value and a value which has subtracted '1' from a unit elapsed value is taken and stored in the timer auxiliary elapsed value area, a value adding a fraction to the elapsed time is brought to (n)-bit shift and its value is subtracted from the timer elapsed value. In such a way, a timer instruction can be processed with high accuracy and at high speed.