| 摘要 |
PURPOSE:To reduce the needed number of backup memory units to one by using a backup memory unit, installed in a subordinate station and master station with a memory unit, through a public circuit. CONSTITUTION:Several subordinate stations 1 are provided which has a CPU controlled by both programs stored in a nonvolatile memory ROM and data in a volatile memory RAM and the function of calling master station 3 via public circuit 2 right after the power is put to work when the memory RAM becomes volatile due to the cutting-off of the power supply. Then, subordinate station 1 controls an uncontrolled unit via an input-output I/O connected to the CPU. Once the cutting- off of the power supply is detected, the function is switched automatically to a fault program function and the contents of memory unit DRUM such as a magnetic drum provided to master station 3 are stored automatically or manually in the RAM via public circuit 2; and after data are all stored, information on a data transfer end is transmitted, thereby stopping the fault program to run. |
