Patent ID: 8598865

Claim:
A measuring device with measuring- and operating electronics, said measuring- and operating electronics serve for determining and/or monitoring at least one measurement signal of a physical and/or chemical, measured variable of a measured substance, said measuring- and operating electronics has at least one control unit and an electrical current controller, and said measuring- and operating electronics is connected to a current loop, wherein a measurement signal current in the current loop represents a measured value of the measured variable, said control unit is connected with the electrical current controller and provides the electrical current controller with a reference input, said reference input corresponds to a desired value of the measurement signal current, said electrical current controller is fed a primary feedback signal, the primary feedback signal corresponds to an actual value of the measurement signal current set in the current loop, the primary feedback signal and the reference input are applied to an input of the electrical current controller, and said electrical current controller outputs a control signal formed from a control error signal between the primary feedback signal and the reference input, said measuring and operating electronics comprises: at least one evaluation unit, said evaluation unit compares at least one value of the control signal output by said electrical current controller with at least one reference value, and the comparison indicates whether the value of the control signal exceeds or subceeds said reference value.