Abstract: A sensor communications system includes different sensor modules which are connected to a master module on a two-wire multidrop transducer bus to provide multiple communication channels. The sensor modules transmit signals to and receive signals from the master module.

Abstract: A method and apparatus for self-testing a transducer system. A signal generator is used to generate a predetermined sequence of signals or pulses, and the sequence has a finite test-time duration. The self-test signal also has the properties that its time varying part: (1) sums to zero over the test time interval; and (2) it has a relatively flat frequency spectrum. Additionally, calculations are made even simpler if the self-test signal is chosen to switch at pseudo random intervals between two fixed values. The output of the self-test system has one term which is directly proportional to the transducer system sensitivity and represents the desired self-test result, and one or more error terms which tend toward zero as the test-time duration increases. The self-testing system of the present invention may be implemented either in analog circuitry, digital logic, or a combination thereof.

Abstract: A system and method for calibrating a transducer having a bridge-type network. The calibration includes a source of constant current and a calibration circuit including the source connected across one of the resistive-type transducer elements of the bridge. Switching means are provided in the calibration circuit so that the current can be selectively supplied to or withheld from the resistive-type transducer element across which the calibration circuit means is connected for producing a calibration signal. The calibration signal is substantially independent of the transducer output regardless of whether or not the signal is temperature compensated and whether it is switched mechanically, electromechanically, or electrically. An internal calibration resistor in the current source is used to make the current inversally proportional to the bridge arm resistance. The calibration resistor tracks the resistive-type transducer elements of the bridge over temprature.