| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily and safely switch an input circuit and an output circuit during plant operation. SOLUTION: To maintain one of output circuits 5a-5n of an output unit 31, a preliminary output circuit 50 is set, a necessary signal is inputted by a maintenance setter 12, and the preliminary output circuit 50 is actuated by access from an arithmetic unit 1; and the circuit to be maintained performs a specific process until the preliminary output circuit 50 is completely started up and after the preliminary output circuit 50 is completely started up, an output control part 41 and a switching circuit 42 performs switching from the circuit to be maintained to the preliminary output circuit 50. Further, an extraction decision part 25 recognizes that the preliminary output circuit 50 has been started up and the output control part 41 has no access to the output circuit to be maintained and a display part 14 is used to show whether or not the output circuit to be maintained is extracted to an operator.</p> |
