Control system primarily responsive to signals from digital computers.

摘要

A computer arrangement (15) provides control signals on lines (17) to an apparatus. The arrangement (15) includes dissimilar first and second digital computers (30, 31) responsive to signals on input lines (14) and provided with distinct programs for alternate generation of nominally idential first and second output signals (C1, C2) respectively, the first computer (30) also generates limiting values (L2) for the second output signal (C2) and the second computer generates limiting values (L1) for the first output signal (C1), each limiting value (L1, L2) bewing generated concurrently with its corresponding output signal (C1, C2). Unacceptable differences between the output signals (C1, C2) and their respective limiting values (L1, L2) cause control of the system to be switched by a device (91) to a further computer (92). Unacceptable differences between the control signals (C1, C2) or between the limit values (L1, L2) may cause control to be transferred to the further computer (92) or to a separate arrangement generally similar to the arrangement (15).