this means that for each neuron on the map it is possible to ascertain the associated process values of all of the basic process variables a neuron on the som accordingly corresponds to a concrete state of the plant the difference between two arbitrary neurons on the map may accordingly be ascertained by comparing the weight vectors w of these two neurons with each other since two neurons m and n represent two different plant states m and n the result obtained from a difference analysis is the differences for all of the process variables which bring about the difference between the process states m and n the following equation illustrates the calculation by way of example the difference var i for process variable pv i is given as the absolute magnitude abs of the difference between the corresponding components w i in the states m and n multiplied by the scaling factor scal_factor starting with this difference it is possible to ascertain the percentage difference diff i based on the measurement range of the process variables i for each process variable pv i of the two plant states m and n it is therefore possible to calculate the influences of the individual process variables pv i on the two process states m and n and to represent.