Uncovering a Defective Rider Roll Load Cell
Shifts in load cell calibrations or defective load cells cannot be detected in closed loop systems, since the control is continuously aligning the load cell feedback signal on the reference.
Among the 450 KPIs calculated on every production cycle (approx. every 10 min.), we compare the rider roll load from load cell signals against calculated load derived from cylinder pressure.
In this specific case, a shift in the calculated load compared to the load cell level was detected.
The SPN continuous and automated data analysis system alerted the mill and triggered our experts’ attention.
Further diagnostic revealed that the shift in effective load was significant and most likely a result of a defective load cell signal.
A report was sent to the mill with specific recommendation to verify the wiring of the load cell and power supply at the controller.
Mill found a loose connection on the load cell amplifier card which affected the level of the load cell signals. The connection was tightened which restored the normal level of the load cell feedbacks.
Detection of this issue allowed the mill to limit the production of defective rolls (loose structure) and avoid shipping them to the customer.
Without the SPN continuous analysis service, this issue could have gone undetected resulting in significant losses due to product rejection by the customer and deterioration of client satisfaction.