Once the above information is obtained a detailed model specification is written which defines precisely how the model will be expected to behave once completed. The specification is then used as a basis upon which the mathematical models are developed. In parallel with this aspect of the development, the graphical displays for the system being considered are designed. During their design specific reference is made to ensuring that the method of control will be similar to that used in the actual plant and at the same time keeping the operation of the simulator simple. An iterative process is undertaken throughout between the development of models and the displays which results in refining of the specification to ensure that all the required aspects of the model can be controlled by the operator or instructor in the required manner.

Once the basic model is completed, detailed system testing is undertaken primarily by undertaking all the necessary operations and checking the results against either expected or real data (where possible) to provide comparisons. The model is then ‘fine-tuned’ so that the simulation compares realistically with the actual data.