| 摘要 |
PROBLEM TO BE SOLVED: To exactly match time of plural programmable controllers connected with a network. SOLUTION: The programmable controller at an upper layer calculates time from transmission of a time counting command according to timing of a CPU interruption signal 15 synchronized with voltage waves of a commercial power source 1 (d1), reception of the command by the programmable controller at a lower layer (d2) to return of a response command according to the timing of the initial CPU interruption signal 15 (d3). And a time setting value is defined by adding the time of the programmable controller at the upper layer to the calculated time and transmitted according to the timing of the CPU interruption signal (d5). The time is switched to the time setting value received according to the timing of the initial CPU interruption signal 15 (d7) after receiving the time setting value (d6) by the programmable controller at the lower layer. |
