Abstract: To provide for continuous synchronized operation of a plurality of computer apparatus units (A, B, C) of a computer system, the respective units generate starting signals at predetermined stages in the programs. The starting signals are transmitted from any apparatus unit to any other apparatus unit, and in each apparatus unit, the time of reception of the starting signals is determined and the last-to-arrive starting signal is determined. Time marker signals are generated, and the time marker signals are transmitted from any apparatus to each other apparatus unit, to be compared in each other apparatus unit with locally generated time marker signals to thereby generate synchronizing signals.

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.

Abstract: The invention is directed to a circuit arrangement for controlling the current through an electric load such as an electromagnetic load. A current-controlling element controls the current through the load in response to a control unit. The voltage at the load is compared with a voltage which depends on the control unit which drives the current-controlling element. The current through the electric load is then controlled in dependence upon the result of this comparison. An embodiment is described by means of which the entire circuit arrangement is protected against function failures or even destruction.

Abstract: A device for controlling and/or regulating current flowing through an electromagnetic consumer, particularly in a control system of an internal combustion engine, is based on the separation of the control of current intensity through the consumer from the control of the direction of this current. This separation is achieved by the provision of a bridge circuit of four current amplifying units whose one diagonal branch is formed by the electromagnetic consumer and the other diagonal branch is formed by a series connection of power source an additional current controlling unit and a measuring resistor. The additional current controlling unit is controlled by a separate current intensity control signal whereas the bridge circuit is controlled by another, current polarity control signal.

Abstract: A capacitor (12) which, by its charge or discharge, times the interval between successive signals at a computer output point which is being monitored so as to provide a reset signal to the computer when the interval exceeds a predetermined normal value, is held in a charge condition which produces a reset signal to the computer component, for a predetermined time after power is turned on. In one embodiment a transistor in circuit with resistances and another capacitance is used for that function and in another embodiment an additional comparator responsive to the rise of the supply voltage up to a threshold value provides that function. The circuit can be designed to provide reset signals of either logic value (0 or 1).

Abstract: A method is proposed for self-monitoring of microcomputer-controlled network devices (10) in motor vehicles which in accordance with applied transducer signals execute specified functions and upon detecting an error store a corresponding data word in memory. For indicating the error, the data word is converted into a signal train or voltage and detected by means of voltage measurement. This is preferably accomplished by inserting a diagnosis insert-plug (42) between the transducer lines and the network device (10). A voltmeter (47) can be connected to this test adapter and indicates this signal train or voltage. A specific type of error is associated with a specific voltage. As a result, a diagnosis which is as detailed as desired, of a complicated system, can be performed with a simple voltmeter (47) available in commerce.

Abstract: A sensor for the variable underpressure in the intake manifold of an engine produces a digital output signal which is sampled at intervals of one half of the period of pressure variation or an odd multiple of such half period, as timed in synchronism with the crankshaft revolution in a phase relation designed to intercept maximum and minimum values of pressure. The two most recent samples are stored in a shift register and their difference is formed by digital subtraction, compensated for changes of sign in successive difference operations to provide an absolute difference value output. The latter is then provided to a threshold stage which provides an output signal if the difference value does not reach a predetermined threshold. The signal of the threshold stage is integrated before it is used to produce an alarm indication or a corrective control function.

Abstract: To obtain high accuracy of the control current in spite of tolerances of operation of the positioned element, a current mirror circuit (18) is provided having two current paths (17, 23). A low resistance resistor (11) is connected in series with the positioned element and the first current path (17) of the current mirror circuit. A command element (22) is connected in the second current path (23) of the current mirror circuit and connected to a command value--actual value comparator (24, 26). Thus, high accuracy of operation and control current is obtained in spite of wide tolerances of the positioning element. Losses in the system are minimized by using pulse width--modulated control thereof.

Abstract: Repetitive processes in internal combustion engines which are dependent upon the values of particular parameters are controlled either by a main computer or an auxiliary computer. Switching from the main to the auxiliary computer takes place if a sequence error detecting stage detects errors in the desired alternation between the main control signals furnished by the main computer and reference mark signals indicative of predetermined angular positions of a shaft of the engine. Specifically, the system is switched to operate under control of the auxiliary computer if such an alternation error occurs again within a predetermined number of cycles. The switching can also take place as a result of missing reference mark signals and as a result of the absence of monitoring signals indicative of correct operation of the main computer program.

Abstract: A pulse for resetting computing equipment is generated upon a drop in the supply voltage. In a first embodiment of a circuit furnishing such a reset pulse, a comparator is used whose inverting input is connected to the supply line through a capacitor and to ground potential through a parallel diode-resistor combination. The direct input is connected to the tap of a voltage divider and is connected through a feedback resistor to the output. This circuit can detect drops in supply voltage in the order of the forward drop across the diode. Alternatively, a RC oscillator can be used to generate a reset pulse. If the capacitor in the circuit is not recharged in time by a pulse furnished by the computing equipment being controlled, it is assumed that failure to receive the pulse is indicative of a drop in supply voltage.