MRP Planning Modes
MRP can be run in three operational modes:
• Regenerative MRP plans for all items at selected sites.
• Net change MRP plans only for items that have changed since MRP was last run. It produces the same results as regenerative MRP, but generally requires less time to execute.
• Selective MRP plans only for the items you select.
Net Change Materials Plan
Net Change Materials Plan (23.1) considers only items with MRP Required set to Yes in their item planning data. The system sets this field to Yes automatically when changes occur for an item in any of the following areas:
• Item or item-site planning data
• Product structures
• Sales or purchase orders
• Work orders or repetitive schedules
• Inventory
• Forecasts
• Master production schedule
• Intersite demand
In addition to planning items that have changed, net change MRP recalculates lower-level requirements for items planned. Typically, Net Change MRP is run daily.
Both net change and regenerative MRP plan items based on low-level codes. They determine requirements at the top level first, then continue down through the item structure, one level at a time.
Regenerative MRP
Regenerate Materials Plan (23.2) recalculates demand and plans supply for all items in the site. The outputs of net change and regenerative MRP are the same. However, net change MRP generally runs faster than regenerative, since it only plans for items that changed since MRP was last run.
You should always schedule periodic regenerative MRP runs, even if you primarily use net change MRP, since net change MRP does not consider demand or forecast for items entering the MRP horizon over time.
Note: The first time you run MRP, it should be regenerative.
Selective Materials Plan
Selective Materials Plan (23.3) plans only for items and sites you select. It can be run in net change mode by setting the Required Items Only field to Yes, or in regenerative mode by setting Required Items Only to No.
You can use Selective Materials Plan to plan master schedule items separately from other items, or to plan small groups of items by using buyer/planner, product line, group, type, supplier, or any combination of these, as selection criteria.
Set MRP Items to Yes to generate planned orders for items at the specified sites and gross requirements for DRP items. Set DRP items to Yes to generate intersite requests for DRP items.
Selective MRP recalculates demand and plans supply only for selected items, passing down gross requirements to the next non-selected level, but not replanning orders. It does not implode product structures to replan higher-level items before planning selected items, nor does it explode resulting orders to calculate component demand.
See User Guide: QAD Supply Chain Planning.