of the measurement behavior of the pressure measurement cell 2 is avoided the capacitance of the pressure measurement cell 2 is determined using the principle of time to digital conversion by an integrated time to digital converter 3 and is converted by the evaluation unit 4 into a corresponding pressure value the pressure sensor 1 as shown in fig4 also has a data interface 5 via which the detected operating state can be output the data interface binary switching output being switched when the operating state is recognized and moreover an analog output is provided via which different operating states can be made recognizable on a differentiated basis another embodiment of a sensor in accordance with the invention not shown here conversely has a data interface 5 with a serial interface protocol in another preferred embodiment of the sensor 1 which is however not shown here the sensor 1 additionally comprises a display unit for displaying the operating state or alternatively for displaying the deviation from an operating state in another embodiment of the sensor in accordance with the invention which is not shown data can also be delivered to the sensor 1 from externally via the data interface 5 for example analog and or digital data fig5 shows an embodiment of a diagnosis device 7 in accordance with the invention for detecting the operating state of a pump in a pump system for transport of.