For either file, you must specify a valid location code as defined in the Location Master File.
If the machine master locations are blank, then the work center locations are used. There are cases where you may want to do a combination between the two in defining the locations.
Let’s say the end item has one operation. The operation is at work center 510 and Machine A is in the work center. You have locations setup in both the Work center file and the Machine master File. You report 100 complete at the work center without specifying the machine.
In this case, the inventory will be processed based on the locations defined in the work center file. If the transaction included the machine number, then the locations in the machine file would be used.