The terms “running the planning worksheet” or “running MRP” refer to the calculation of the master production schedule and material requirements based on actual and forecasted demand. The planning system can calculate either Master Planning Schedule (MPS) or Material Requirements Planning (MRP) on request, or it can calculate both at the same time. Tip to my readers, run them separately to avoid any confusion.
• MPS is defined as the calculation of a master production schedule based on actual demand and the production forecast. The MPS calculation is carried out for end items that have a forecast and/or a sales order line. These items are called “MPS items” and are identified dynamically when the calculation starts.
• MRP is defined as the calculation of material requirements based on actual demand for components and the production forecast on the component level. MRP is calculated only for items that are not MPS items. The overall purpose of MRP is to provide time-phased formal plans, by item, to supply the right item at the right time, in the right place, in the right quantity.
The planning algorithms used for both MPS and MRP are identical. The planning algorithms concern netting, reuse of existing replenishment orders, and action messages. The planning system process looks at what is needed or will be needed (demand) and what is on-hand or expected (supply). When these quantities are netted against each other, the program provides action messages. Action messages are suggestions to create a new order, change an order (quantity or date), or cancel an order already on order. The term “order” includes production orders, purchase orders, and transfer orders.
Proper planning results depend on the set up done on Item Cards, Production BOMs, and Routings. When you are first setting up NAV,test the effects of changes on the item card’s parameters as it relates to the results of the planning worksheet’s recommendation.