| 摘要 |
<p>PURPOSE:To confirm a contact which changes in state at a glance by providing a processor which compares current and last state data with each other and detects the address of the contact having a change in opening/closing state and a ring buffer stored with the address of the detected contact and the state after the state change together with the time that a timer indicates. CONSTITUTION:The processor 10 reads state data indicating the opening/closing state of the contact out of an input/output module 1 and ORs the current state data exclusively with the last state data stored in an I/O memory 11 for comparative arithmetic to detect the address of the contact which has the change in opening/closing state. The ring buffer 14 is stored with the address of the contact having the change in the opening/closing state and the state of the contact after the state change together with the time that the timer indicates. A CPU 6 sends the data stored in the ring buffer 14 to a personal computer 9 through an interface 8 and displays a timer chart. Consequently, an operation history can be confirmed without omitting data and the contact having the state change can be confirmed at a glance.</p> |
