A method of predictive monitoring of a variable of a medium located in a container of a facility and of a measurement accuracy of a measurement device measuring the variable and providing measured values of the variable during operation of the facility, wherein the facility is configured to repeatedly perform a batch process, a production process, or laboratory analyses, the method comprising the steps of:
- installing the measurement device at the facility with the measurement device measuring the variable of the medium and providing measured values of the variable;
- operating the facility independently of the measured values of the variable provided by the measurement device, wherein operating the facility includes the facility repeatedly performing specific operation phases of the batch process, the production process, or laboratory analyses, wherein measured values measured during the specific operation phases exhibit a characteristic distinguishing these measured values from measured values measured during other operation phases, and wherein the characteristic corresponds with a reference characteristic when the facility is operating properly and the measurement device corresponds to a specified measurement accuracy during the respective specific operation phase;
- during operation of the facility continuously recording data including the measured values measured by the measurement device and their time of measurement;
- identifying data sets included in the recorded data that have been measured during the specific operation phases based on training data comprised in the recorded data, which has been recorded during a training time interval during which the facility was operating properly and during which the measurement device operated accorded to the specified measurement accuracy;
- monitoring the variable of the medium and the measurement accuracy of the measurement device by:
- based on the data sets, comparing compliancy indicators indicative of a degree of compliancy of at least one property of the characteristic of the measured values comprised in the data sets to a corresponding reference property of the reference characteristic;
- based on a time series of the determined compliancy indicators at least once determining a remaining time remaining until the degree of compliancy indicated by the compliancy indicators to be determined based on measured values to be measured during a future occurrence of the specific operation phase will drop below a predetermined minimum degree of compliancy;
- providing an output informing about the remaining time;
- calibrating the measurement device at or before the point in time at which the degree of compliancy indicated by the compliancy indicators will drop below the minimum degree of compliancy according to the previously determined remaining time;
- during calibration determining a measurement error of the measurement device;
- in case the measurement error is smaller than a predetermined threshold performing at least one of:
- determining an impaired operation of the facility as root cause causing the degree of compliancy to drop below the minimum degree of compliancy, and determining a fault causing the impaired operation and applying a remedy resolving the fault;
- and
- in case the measurement error is larger than a predetermined threshold performing at least one of:
- determining the impaired measurement properties of the measurement device as root cause causing the degree of compliancy to drop below the minimum degree of compliancy, and adjusting, repairing or replacing the measurement device, which is compliant to the measurement accuracy specified for it.