| 摘要 |
<p>PURPOSE:To switch the clock when the alarm appears at the entire system, by using that the monitor and alarm function in each system operates without fail if there is any failure in the clock relating to monitored area. CONSTITUTION:When the clock fed to the systems 6-n from the clock distribution boards 3, 4, is of two types, if there is any failure in the clocks, any alarm is produced from each system. That is, if one clock should fail, alarm as is produced and alarm ac is developed if other clock is in failure. Since the alarms produced at clock failure is common to the systems 6-n, the logical product is taken at the AND circuits 8a, 8b as to all the systems for the alarms as, ac, and the result is made to logical sum at the OR circuit 9. The signal SA indicating the failure of clock is obtained and switching is made based on this.</p> |
