Endress+hauser Gmbh+co.

Martin Pfandler

Volker Dreyer

Bernd Strutt

Arthur Schrock

The transducer supply is configured for supplying a passive transducer arranged in an explosion-hazard zone with electrical energy from a DC voltage source. The electrical energy is transmitted via a two-wire connection, via which in the opposite direction the measured value sensed by the transducer is transmitted by the transducer setting the direct current obtained from the DC voltage source to a value variable between two limit values. As a means of protection a transformer is inserted in the two-wire connection which affects DC decoupling. The direct current is chopped in accordance with the principle of a DC voltage converter at the primary side of the transformer and re-rectified on the secondary side. To permit connection of an active transducer instead of a passive transducer, the active transducer having its own energy supply and furnishing at its output connections a direct current in a quantity representing the measured value, an adapter circuit controlled by the output current of the active transducer is inserted between the output connections of the rectifier circuit and the connecting terminals provided for connecting the active transducer, this adapter circuit loading the rectifier circuit with a direct current which is proportional to the output current of the active transducer.

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Maulburg, Germany

Martin Pfandler