DRP and MRP
To manage the supply, demand, and resources of a supply chain, DRP must be integrated with MRP. The two systems are complementary. MRP balances supply and demand within a site, while DRP balances supply and demand between sites.
See User Guide: QAD Manufacturing.
MRP considers intersite requests as demand at the supply site. Therefore, when to run DRP in relation to MRP depends on where distribution items appear in the product structures for that site.
• For sites that distribute finished products, you usually run DRP before MRP to generate demand for those products at other sites.
• For sites that supply component items to other sites, run MRP first.
If you have DRP items at multiple levels of product structures for a site, you can also run MRP and DRP in combination. MRP and DRP take advantage of the intersite low-level codes. MRP/DRP Combined, a field in both MRP Control (23.24) and in DRP Control (12.13.24), allows MRP to pass gross requirements to DRP items. DRP creates the intersite request, creating demand at the supply site. The item at the supply site is then planned by MRP.
Running MRP and DRP in combination is especially useful if you use centralized purchasing—common materials are purchased by multiple sites from common suppliers. Lowest-level items (the items highest in your bills) are processed first, regardless of site, and all purchase orders are planned after all site and intersite demand has been calculated.
If you choose to run MRP and DRP separately, MRP creates gross requirements for DRP items, but then does not use DRP to plan the intersite request. MRP simply completes the site or sites where it is run.
A later DRP run explodes the gross requirements for distribution items and creates the intersite requests. These should now be exploded at the supply site using MRP. The only advantage of running the two programs separately is that the processing times are separated into two periods—a possible requirement if there are hardware limitations.