| 摘要 |
<p>PURPOSE: To enable the continuation of an accurate time control and also automatic modification of a clock which a controller has, by detecting a failure quickly when it occurs in the clock of the controller. CONSTITUTION: In a timing system equipped with a control center 1 having a time counting function, a controller 2 conducting a time control of a device to be controlled and a communication circuit connecting them, a master clock 5 and a sub-clock 22 used for the time control of the controller 2 are provided, and when a detecting means 23 detects abnormality of the master clock 5, the time control in the controller 2 is switched from the master clock 5 over to the sub-clock 22 by a switching means 21. After completion of this switching, a modifying means 24 takes time count data from the control center in the master clock 5 through the communication circuit and executes modification.</p> |
