A method for preparing block diagrams having one or more blocks for code generation in a computing environment comprising a model editor, a data definition tool and a code generator. The block diagram is opened in the model editor, wherein a first block is a hierarchical block comprising a plurality of subordinate blocks, at least one input port and at least one output port connected by signals. Minimum values and maximum values are received for the input and output ports, determining scaling parameters for the input and output ports based on the received minimum and maximum values. Scaling parameters are determined for each subordinate block in the first block, wherein the scaling parameters of at least one subordinate block are determined based on the scaling parameters of at least one output port. Also, a method for generating program code, a non-transitory computer readable medium and a computer system are provided.