| 摘要 |
PROBLEM TO BE SOLVED: To improve usability for refreshing a device memory in a programmable logic controller (PLC).SOLUTION: A PLC repeatedly executes a user program for every scan. A first update unit 75 refreshes data held by an expansion unit and data held by a basic unit in a refresh period of a scan time. A second update unit 76 refreshes data held by the expansion unit and data held by the basic unit in a fixed period of the scan time.SELECTED DRAWING: Figure 7 |
