Monitoring and diagnostic system for a fluid energy machine system, wherein the fluid energy machine system comprises a plurality of different sub-systems (16, 17, 18, 19, 20, 21, 22, 25, 26) and system components (13, 14, 15, 23, 24), wherein - the monitoring and diagnostic system has a central processing unit, - each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24) can be connected via standardised bi-directional interfaces and via one or more data lines to the central processing unit for the purpose of data communication, - each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24) has at least one sensor element for determining status information for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24), - at least one control device is provided for controlling the sensor elements, - a memory device is provided for storing the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24) and also for storing comparison data for the purpose of operating the fluid energy machine system, - a comparator unit is provided for comparing the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24) with defined threshold values for each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24), and - a display device is provided for displaying the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24), and also for displaying an alarm in the event of an undershoot or overshoot of a threshold value in the case of a sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) or a system component (13, 14, 15, 23, 24). - the monitoring and diagnostic system has a central processing unit, - each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24) can be connected via standardised bi-directional interfaces and via one or more data lines to the central processing unit for the purpose of data communication, - each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24) has at least one sensor element for determining status information for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24), - at least one control device is provided for controlling the sensor elements, - a memory device is provided for storing the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24) and also for storing comparison data for the purpose of operating the fluid energy machine system, - a comparator unit is provided for comparing the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24) with defined threshold values for each sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and each system component (13, 14, 15, 23, 24), and - a display device is provided for displaying the status information determined for the respective sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) and the respective system component (13, 14, 15, 23, 24), and also for displaying an alarm in the event of an undershoot or overshoot of a threshold value in the case of a sub-system (16, 17, 18, 19, 20, 21, 22, 25, 26) or a system component (13, 14, 15, 23, 24).