A data storage apparatus for a numerically controlled machine tool comprising a control device for controlling a plurality of actuators of said machine tool and a plurality of sensors for outputting sensor signals indicating a machine status of said machine tool to the control device, said data storage apparatus comprising: a first interface unit for data transmission with the numerical control device of said machine tool, a first storage medium for storing configuration data indicating a group of sensors of said machine tool and readout and processing rules for sensor signals of the group of sensors of said machine tool, a readout unit for reading out sensor signal values of the sensor signals of the group of sensors of said machine tool indicated in the configuration data via said first interface unit on the basis of the readout rules indicated in the configuration data, a data processing unit for processing the sensor signal values read out by means of said readout unit into aggregated sensory data on the basis of the processing rules indicated in the configuration data, a second storage medium for storing the aggregated sensory data processed by said data processing unit, and a second interface unit for data transmission with an external data processing device (220; 400; 500), via which said external data processing device (220; 400; 500) can access sensory data stored in said second storage medium, wherein said second interface unit is configured to transmit sensory data stored in said second storage medium to a server via a local or global network; said second interface unit is configured to grant said external data processing device (220; 500) or said server access to configuration data stored in said first storage medium for modifying the configuration data; said second interface unit is connected to a man-machine interface of the control device of said machine tool for transmitting the sensory data stored in said second storage medium and/or the configuration data stored in said first storage medium to said man-machine interface for display on a graphical user interface of said man-machine interface of the control device of said machine tool, wherein, when said external data processing device (220; 500) or said server determines or predicts based on the sensory data and/or the configuration data that maintenance is to be carried out on said machine tool, instructional data are transmitted to said man-machine interface and displayed via said graphical user interface. a first interface unit for data transmission with the numerical control device of said machine tool, a first storage medium for storing configuration data indicating a group of sensors of said machine tool and readout and processing rules for sensor signals of the group of sensors of said machine tool, a readout unit for reading out sensor signal values of the sensor signals of the group of sensors of said machine tool indicated in the configuration data via said first interface unit on the basis of the readout rules indicated in the configuration data, a data processing unit for processing the sensor signal values read out by means of said readout unit into aggregated sensory data on the basis of the processing rules indicated in the configuration data, a second storage medium for storing the aggregated sensory data processed by said data processing unit, and a second interface unit for data transmission with an external data processing device (220; 400; 500), via which said external data processing device (220; 400; 500) can access sensory data stored in said second storage medium, wherein said second interface unit is configured to transmit sensory data stored in said second storage medium to a server via a local or global network; said second interface unit is configured to grant said external data processing device (220; 500) or said server access to configuration data stored in said first storage medium for modifying the configuration data; said second interface unit is connected to a man-machine interface of the control device of said machine tool for transmitting the sensory data stored in said second storage medium and/or the configuration data stored in said first storage medium to said man-machine interface for display on a graphical user interface of said man-machine interface of the control device of said machine tool, wherein, when said external data processing device (220; 500) or said server determines or predicts based on the sensory data and/or the configuration data that maintenance is to be carried out on said machine tool, instructional data are transmitted to said man-machine interface and displayed via said graphical user interface.