RESISTANCE MEASURING CIRCUIT FOR SENSOR WITH GALVANIC ISOLATION Russian patent published in 2009 - IPC H02H7/08 G01K7/16 

FIELD: electricity.

SUBSTANCE: invention is based on the electronic circuit where sensor conductors located inside the measured item are coupled with the amplifier of feedback coupling. The above amplifier reduces DC voltage supplied to the potential divider when sensor resistance is increased. The measured signal is intensified and compared with the output voltage of saw-tooth voltage generator by means of comparator. After that, the sustained pulse-modulated signal is generated and transmitted in digital form to the electronic circuit SELV (safe low-volt voltage), for example, via optoisolator. After amplification, the logarithmical form of signal representation enables precise measuring of the difference between short circuit in the sensor circuit and low values of resistances.

EFFECT: improved reliability and measuring accuracy.

6 cl, 5 dwg