Shut=down circuit for computer-operated process - compares generated pulse with that processed by computer to ensure correct operation

摘要

This shut-down circuit stops an automatic processing system (3) if the computer (1) which controls the process is faulty. A generator (4) delivers a pulsed reference signal to the computer (1) and one input of the signal comparator (5). If the computer is working correctly, it treats the pulse as an interrupt and produces an identical signal which is fed to the other input of the comparator, via a low pass filter (7) which removes any undesired h.f. components. If the comparator detects problems with the computer, it delivers a signal to the process cut-out circuit (6), and shuts down the process. A feedback link (8) from the cut-out circuit to the computer forces the computer to yield control if the cut-out does not work. A process monitoring signal (9) to the computer may be used to provide extra protection.