Patent ID: 7496458
Filing Date: 2009-02-24
Classification: G01D

Abstract:
1. An electrical transducer using a two-wire process comprising: an analog sensor that detects a quantity to be measured; an analog end stage which is connected downstream of the sensor at the output end of the transducer; a processor circuit; and wherein the processor circuit is not connected serially between the sensor and the analog end stage so that a separate analog measurement signal transmission path is realized, the analog end stage converting an output signal of the sensor into an impressed output current with a magnitude which is a measure of the quantity to be measured and is fixed within a range of about 0 to 20 mA, the electrical transducer being controlled by the processor circuit, wherein during normal operation of the electrical transducer, the processor circuit is shifted temporarily from an awake mode into a sleep mode in which the processor circuit is inactive, the analog measurement signal transmission path including an analog scaling unit, the output signal of the sensor and at least one analog setting value are supplied to the analog scaling unit, and the output signal of the analog scaling unit is supplied to the analog end stage; wherein the output signal of the sensor is routed past the processor circuit via the analog signal transmission path when the processor is in said sleep mode for enabling changes in the quantity being measured to be followed while the processor circuit is inactive; wherein the processor circuit has an activity time in which the processor circuit is active which is shorter than the time that the processor circuit remains in the sleep mode; wherein the analog scaling unit comprises an analog arithmetic circuit; wherein said at least one analog setting value is a DC voltage signal or a direct current signal which is delivered to the analog arithmetic circuit of the analog scaling unit; and wherein at least one active integrator is connected to the processor circuit and to the analog scaling unit as an actuator for producing said DC voltage signal or direct current signal.