Calculating Basic Dates (SAP Library - Material Requirements Planning (PP-MRP))

Calculating Basic Dates

Implementation Options

The basic dates determine the outermost time limits for production. During material requirements planning and forecast-based planning, the system calculates the order start and finish dates in addition to the order opening date of the planned order.

Prerequisites

You have determined the goods receipt processing time (in workdays) in the material master (view MRP 2).

You have defined a lot size dependent or independent in-house production time in workdays (see In-House Production Time: Independent of Lot Size, In-House Production Time: Dependent on Lot Size).

You have defined the opening period for each plant in Customizing for MRP in the IMG activity Define floats (scheduling margin key).

The opening period is the time required by the MRP controller to convert the planned orders into purchase requisitions. It is only taken into account with backward scheduling.

Process Flow

The system always determines the basic dates for planned orders using backward scheduling.

The system automatically switches to forward scheduling if the determined start date lies in the past.

If you do not want the system to switch to forward scheduling automatically, you can specify per plant in Customizing for MRP, in the IMG activity Parameters for determining the basic dates that the system is to continue the backward scheduling calculation even if the resulting start date lies in the past.