Patent ID: 8850880

Claim:
A diagnostic system for a valve, comprising: a drive; a position controller having a housing and being fastened on the valve by the housing, the valve being actuatable by the position controller via the drive; a first temperature sensor on or in the housing of the position controller, the first temperature sensor having a high level of thermal coupling with the valve and a low level of thermal coupling with an environment; a second temperature sensor on or in the housing of the position controller, the second temperature sensor having at least one of a lower level of thermal coupling with the valve and a higher level of thermal coupling with the environment than that of the first temperature sensor; and an evaluation device configured to compare a first temperature value, acquired by the first temperature sensor, with a second temperature value, acquired by the second temperature sensor, and to output a signal indicating a valve leak when the first temperature value is lower than the second temperature value by more than a prescribed maximum deviation.