| 摘要 |
<p>In a programmable controller having a function for referring to a reference clock signal every cycle time and updating the present value of a count in a user timer upon confirming that the reference clock signal has changed state, execution time of a user program is measured from the start of execution thereof in each cycle time, it is determined whether the measured execution time has exceeded a minimum unit time of the reference clock signal, and the present value of the count in the user timer is updated even if the minimum unit time has been exceeded. As a result, the present value of the user timer count can be updated with certainty even if the user program execution time is so long that the minimum unit time is exceeded.</p> |
