MRP Run for a Supersession Chain
Use
To avoid unnecessarily large surplus stock arising for a discontinued product, or requirements not being covered, procurement planning can never be executed for an interchangeable product independently of the other products in the supersession chain. Procurement planning must ensure
That surplus stock and fixed receipts of a discontinued product are consumed by requirements of the product or the successor products, if this is permitted
That requirements for a discontinued product are covered by valid successor products
An MRP planning run with the standard heuristic SAP_MRP_001 takes account of these requirements automatically. If you call the MRP heuristic for one product in a supersession chain in the production planning run or in interactive planning, the system automatically plans all products in the supersession chain in the sequence defined by the supersession chain. The system calls the product heuristic for the procurement planning of a product. If required, the product heuristic forwards requirements and stock or fixed receipts of a discontinued product along the supersession chain to the successor product.
The same applies:
If you call the
Product Heuristic
for an interchangeable product in interactive planning.If the system executes the action
Start product heuristic immediately
for an interchangeable product as a reaction to a planning-relevant event.
The system also plans all the products in the supersession chain here.
Note
The system executes an MRP run in the background when calling up the
product heuristic
in interactive planning or using the action
start product heuristic
immediately. The system uses an MRP heuristic with settings that are defined by SAP.
Common planning of products in a supersession chain in the MRP run is made necessary as the products belong to one planning package , which the system automatically creates for the products in the supersession chain.
Prerequisites
General Prerequisites
You have defined the master data for planning with product interchangeability . In particular, as product heuristic, you have entered a procurement planning heuristic, which is suitable for planning interchangeable products, in the location product master for the products that are in the supersession chain.
MRP Heuristic
You need to have defined in the settings for the MRP heuristic that the system should use the
Product Heuristic
for the procurement planning of a product. This is relevant if you do not use the standard heuristic SAP_MRP_001.MRP Planning Run in the Production Planning Run
You need to have defined the following processing steps for the production planning run:
A processing step that calls the heuristic SAP_PP_020, for example, to determine the low-level codes
This is necessary if you do not execute low-level code determination beforehand in an independent production planning run.
A processing step that calls the heuristic SAP_MRP_001
NoteBefore this processing step, there must not be a processing step that calls a procurement planning heuristic directly for the products in a supersession chain. In a processing step like this, the system would plan the products in the supersession chain that you have specified for the processing step. However, the following problems would occur:
The system plans the interchangeable products in any sequence.
As only one MRP heuristic can take planning packages into consideration, the system only processes the products specified in the product selection, and not all products in the supersession chain.
This can lead to incorrect planning. Since the system resets the planning file entries for planned products after planning with the procurement planning heuristic, a subsequent net change planning run would not correct the incorrect planning. Regenerative planning would be necessary for the correction.
End of the note.
Features
To plan the products in the supersession chain in the correct sequence, the MRP heuristic calls up the heuristic SAP_PP_I001, which is entered in the standard system as a package heuristic in the location product master of the supersession chain products. The heuristic SAP_PP_I001 calls each product heuristic for each product one after the other. The heuristic starts with the first product in the supersession chain and processes the products in the sequence specified by the supersession chain.
Caution
Since the heuristic for supersession chains SAP_PP_I001 only functions when integrated with an MRP heuristic, you cannot call the heuristic SAP_PP_I001 directly in productive planning. For example, in the production planning run you cannot define a processing step containing this heuristic. Only the MRP heuristic as service and dispatcher heuristic prepares a planning package correctly for the subsequent planning.
The product heuristic executes the actual procurement planning for an interchangeable product, meaning that it calculates the net requirements and procurement quantities, and creates procurement proposals. The product heuristic takes the limited time validity of the product into consideration here and, depending on the use-up strategy, forwards requirements and stock or fixed receipts to the next successor product. If a requirement has to be covered by another product; for example, by surplus stock from the predecessor product or through procurement of the successor product, the product heuristic creates product substitution orders .