1. A method of tuning a process controller for use in controlling a controlled process, comprising: defining a multiplicity of model parameter values for each of a plurality of model parameters associated with a generic process model, the generic process model being representative of the controlled process; creating a set of individual process models, wherein each of the set of individual process models is formed from the generic process model using one of the multiplicity of model parameter values for each of the plurality of model parameters, and wherein each of the set of individual process models is formed using a different combination of model parameter values for the model parameters; performing a model scan, including; executing each of the individual process models on one or more process inputs to produce a model output for each of the individual process models, comparing the output of each of the individual process models to a process output to determine a model error value for each of the individual process models, for each individual process model, associating the model error value for the individual process model with each of the model parameter values used in that individual process model, and for each model parameter value of each model parameter, computing a model parameter value norm from the model error values associated with that model parameter value; for each model parameter, determining a new model parameter value from the model parameter value norms computed for the multiplicity of parameter values for that model parameter, to create a set of new model parameter values including one new model parameter value for each of the model parameters; and determining one or more process controller tuning values from the set of new model parameter values.