I do know what a mrp profile is, how to create it, change it etc. but what I dont know is where and how do we use it. I have not seen any key or tab indicating mrp profile. Then what is it? What are tcodes mmd1, mmd2 all about?

MMD1 is the transaction code for creating MRP profile. 

In MRP profile you can create your own record or file, when you use the transaction.  Give the name and description to your own profile and you can select the fixed values and/or default values from the option given of the MRP fields.  For eg. if you select or tick the check box against procurement type in the fixed values column then click on screen 1 to fix the value. You get the option of different procurement types, if you select from these option and save , your profile is created .

Now, go to material master in the MRP2 screen and go to main menu -->edit-->MRP profile.   In this, you can assign your profile which has been created by you.  So now you will see that the procurement type has become fixed value for your material and which cannot be changed in the material master . 

You can only do the changes if you change your profile again (MMD2) or do not assign any profile.  Similarly, you can store the default values if you require in MRP profile.                                                  *-- Amitabh Rathod

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