Material Requirements Planning (MRP)

To accurately reflect inventory status, the system accounts for a lot's effective date when calculating time-phased supply inventory and the ability of that supply to satisfy demand during time periods. This table describes this process for MRP:

MRP Element	Use of Effective Dates
On-Hand Inventory	When calculating the available quantities from on-hand inventory, the system uses the effective date of the lot to determine whether the quantity that is associated with the lot is available. If the lot effective date is greater than the period in which supply is being calculated, then the system does not consider the quantity that is associated with the lot to be available for planning purposes in that period. However, if the effective date is less than or equal to the planning period, the system considers the quantity of item that is available to satisfy demand in that period. The quantity in the lot continues to be able to satisfy demand in subsequent periods until the quantity in the lot reaches zero or the lot expires.
Purchase Orders	If the lot's effective date is greater than the period in which supply is being calculated, then the system does not consider the quantity that is associated with the lot to be available for planning purposes in that period. However, if the effective date is less than or equal to the planning period, then the quantity of item in the lot is considered available to satisfy demand in that period. The quantity in the lot continues to be able to satisfy demand in subsequent periods until the quantity in the lot reaches zero or the lot expires. At this time, the system no longer considers the lot available for any purpose. The system searches for an effective date on all purchase order lines. If a purchased item is not lot controlled, the item's purchasing effective days equal zero or blank. In this case, the system adds zero to the promised delivery date, and the planned effective date is equal to the promised delivery date.
Work Orders	The system uses the value in the Planned Effective Date field (DPL) to calculate planned supply availability from work orders. This calculation is based on the work order request date and the manufacturing effective days for the item on the work order as defined in the F4102 table. The system adds the item's manufacturing effective days to the work order's planned completion date to obtain the planned effective date. If the planned effective date is greater than the period in which supply is being calculated, then the quantity of inventory that is associated with the lot is not considered available to satisfy demand in that period. However, if the planned effective date is less than or equal to the planning period, then the system considers the quantity of inventory that is associated with the lot to be available to satisfy demand in that period. The quantity in the lot will continue to satisfy demand in subsequent periods until the quantity in the lot reaches zero or the lot expires. At this time, the system no longer considers the lot available for any purpose.
Time Series	The system considers the effective date when performing the netting operation for planning and when applying supply inventory to the appropriate date. For example, if a lot of 100 of Part A is created on August 1, but does not become effective until August 15, the system does not display the lot as part of the inventory until August 15.
Supply/Demand Inquiry	The system considers the inventory as available based on the planned effective date of the items on the order. When calculating supply from a purchase order, the system calculates availability based on the value in the expected effective date on the purchase order detail line. When calculating supply inventory from a work order, the system calculates availability based on the planned effective date of the work order.