The AOD (Argon Oxygen Decarburization) system is the part of a steel mill, found upstream in the manufacturing process, that modifies the steel composition to give it its main characteristics. The AOD is controlled by a PLC (Programmable Logic Controller) system and a weight measuring instrument is used to choose the quantity of material charged on a hopper. The hopper is then transported to the melted steel so that it can dump its content to change the composition. The weight indication given by the scale has to have a maximum admitted error that is under the threshold of 1% of the weight, so that the characteristics of the final material do not have appreciable variations and, as a consequence, expensive additions do not have to be made afterwards to reach the target composition.