The significance of the number of temperature deviations per cluster is then analyzed. The z value, as it is known, is calculated for this purpose. A high absolute z value indicates that there is a significant correlation between the respective temperature deviation and the characteristics of the cluster concerned (e.g. “thin strip”, “high furnace outlet temperature”, etc.), and that, in all probability, this cannot be put down to coincidence.
With regard to the input parameters (casting speed, furnace outlet temperature, etc.), no significant correlation with the temperature deviation could be found in the present case in question. By contrast, the analysis of the roll IDs showed that the deviation between the setpoint and actual temperature was high with a particularly large number of coils, in cases where the work roll with ID 44 was used or was replaced during the last roll change.
The evaluation of the data using the X-Pact® Performance Enrichment Analysis is continuously performed during plant operation, thus allowing it to detect deviations during production quickly and send reports on the abnormalities. At the same time, a variety of other target variables can be monitored instead of the coiler temperature.