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Where you must track several different products through one or more tanks, it may be useful to define macros for naming each product type. For example, setting ProductA equal to 1 and ProductB equal to 2 will improve the readability of the model. To track which product a particular tank is processing, ProModel uses a pre-defined integer array called Tank_Product—the user is responsible for maintaining the array values. If, for example, ProductA begins pumping into Tank1, enter the following after you assign an integer value to ProductA in the Macros module to distinguish it from other products:
Tracking products
Tank_Product [Tank1] = ProductA