I would like to iterate calculate field in multiple tables using ArcGIS Model Builder. The figure below explains details of the calculations. My existing model calculates value only for the first table.
Any direction would be valuable.
ModelBuilder only allows one iterator per model. I would integrate a model within a model in order to iterate over multiple tables.
If your new fields have a pattern in their naming (e.g., [table_name]_y as in your snapshots), you can use inline variable substitution. More specifically, if you change Field Name parameter to %Name%_y, this will transfer all GRID_CODE values to this field in your individual DBFs.