Device for sensing and discriminating operational faults in an electrical power supply

A device for controlling an electronic switch and for detecting and discriminating between operating faults in a plurality of electrical power supply circuits for a respective load connected in series with a respective electronic switch, said device comprising:

• a plurality of bidirectional input/output control lines, each connected to and provided for carrying control signals for a respective electronic switch and first interrogation signals in one direction and interrogation result signals in the opposite direction;
• a selection line connected to said plurality of electronic switches for carrying second interrogation signals in said one direction;
• a computer connected to said plurality of bidirectional input//output control lines and to said selection line and programmed to place control signal combinations on said bidirectional input/output control lines and said selection line in an interrogation mode and to accept logic status signals as interrogation result signals from said plurality of bidirectional input/output control lines in a read mode;
• a plurality of detection means each connected to the respective power supply circuit of a respective load for detecting at least one operating fault selected from the group consisting of a short-circuit condition of the load, permanent control of the load and an open-condition of the load;
• each of said detection means comprising at least one detector including an input and an output, said input connected to a predetermined point of a respective power supply circuit of the respective load an sensitive to an electrical characteristic at said predetermined point to form a logic signal at said output representative of the value of said electrical characteristic with respect to a predetermined value, a logic circuit including a first input connected to said output of said at least one detector, a second input connected to said selection line and a third input connected to the respective bidirectional input/output contol line, and an output, and a logic signal imposition means including an input and an output, said input of said logic signal imposition means connected to said output of said logic circuit and said output of said logic signal imposition means connected to the respective bidirectional input/output control line, said logic circuit actuated in response to at least one combination of control signals emitted by said computer to detect the presence or absence of a predetermined fault as indicated by the at least one detector and to produce at said output a signal representative of the detected presence or absence, and said logic signal imposition means operable to place a corresponding one of two logic levels respectively representing the presence or absence of said predetermined fault on said output connected to said input/output control line;
• and
• said computer comprising fault identification means connected to said plurality of bidirectional input/output control lines for reading and identifying fault states of the plurality of power supply circuits with respect to interrogated logic circuits.