| 摘要 |
PURPOSE:To establish the selector making unnecessary the I/O exclusive use for the test, by providing the means selecting the input and output unit I/O to the spare control unit in block unit and giving the interlocking function selecting arbitrary I/O individually. CONSTITUTION:When the control unit 3 for present use is in failure, the block selection circuit 9 is operated with the selection signal from the block control section 11 and the I/O DA1 to DAn connected to the control unit of A are selected to the input and output corresponding section 4 of the spare control unit 3 at a bundle. When an arbitrary I/O 1 is used for test with selection, the individual selection circuit 10 is operated with the selection signal from the individual selection control section 12, and the I/O DA1 connected to the control unit I/O corresponding section 4 of A is changed over to the I/O corresponding section of the spare control unit 3. A plurality of I/O's are never connected to the spare control unit simultaneously with the control signal from the interlock control circuit 13 made at the same time. Accordingly, even ON line, arbitrary I/O can be selected for test and I/O for exclusive use test is not needed. |
