Abstract: To prevent spurious operation of a controlled operating element (12), typically a safety element which can be irreversibly triggered, such as a trigger or firing cartridge of a passenger restraint airbag, while providing for reliable operation in case of a crash of a vehicle in which the airbag is installed, a control signal is derived from a computer (10) processing input signals. The transmission of the control signals from the computer (10) to the operating element (12) is through a time delay stage (30) which has a time delay of sufficient length to permit the computer to correct, if necessary, signals from its output (16) and to carry out tests on the output signals from the computer apparatus. An evaluation circuit (18) continuously compares the output signals with check values. The check values may be derived from, for example a second computer similar to the computer, or from stored representative values.

Abstract: To permit rapid checking of possible malfunctions or erroneous computations in data processing cycles, in which a plurality of computer units carry out processing of data, especially to supervise and control safety apparatus, each one of the units generate intermediate information data at predetermined time intervals, which intermediate information data are transmitted to each one of the other units. The so-received intermediate information data are buffer-stored and compared in all the units with locally generated check data. If the comparison indicates coincidence, computation is continued through subsequent processing cycles; if an error is detected, at least that computer unit which processes the data erroneously is reset to repeat at least the preceding computation cycle, and the unit which detected the error is placed into a "set-and-hold" mode.