| 摘要 |
PURPOSE:To improve the responsiveness of control input and output, by comparing output data between an input/output memory and an old data memory to detect an output change and informing the changing frequency when it exceeds a prescribed level to display an alarm through an individual display device. CONSTITUTION:A CPU1 executes a system program stored in a system program memory 2 and carries out the sequence control designated by a user program through a working memory 3, a user program memory 4 which stores a sequence control program set optionally by a user and an input/output memory 7 serving as a buffer memory of an input circuit 5 and an output circuit 6. Futhermore an old data memory 8 and an alarm display device 9 are added. Then the input data is stored in the memory 8, and the changing frequencies are counted for the input data whose changes are confirmed. When this changing frequency reaches a prescribed level, the device 9 is driven. |
