| 摘要 |
<p>PURPOSE:To attain the process control with reduced load of an operator and small number of errors by monitoring the transient and detecting a fault of a valve drive mechanism. CONSTITUTION:A change detecting means 4 always monitors all close and open signals applied to an input scan means 3 and checks whether all close signals have changes or not. When the changes are decided, it is decided whether all close signals are presently kept ON or OFF. If the present state is not fully close, it means that a valve starts opening. Therefore a valve open command signal is turned on without fail. Thus a fault state generation flag is set when it is confirmed that said command signal is kept ON. While the end of the valve closing operation is decided when the present state is fully close. Then a closing operation flag is cleared.</p> |
