| 摘要 |
PURPOSE:To detect an error by utilizing that when periodically-received signals disappear owing to a fault, etc., old data are maintained. CONSTITUTION:Serial input channel signals 15 to 18 composed of frame periodic signals, address information and data are converted into parallel signals by input channel signal converters 4 to 7; and the address information is transmitted to address bus 12, and data are to data bus 13, The address information is converted into proper information by address converter 3 and on the bais of this address information, the data are stored in buffer area 8 of the memory. The pieces of pattern information of 1 and 0, which will not be generated at a normal time are set previously to this buffer area, and its contents are updated by receiving an input signal, so that the quality of the input channel can be discriminated by periodically checking the contents of the buffer area. |
