You use the production planning run to execute planning online or in the background for selected objects. In this case, online planning is only suitable for small data quantities (for example, for test purposes), while you implement background planning for mass planning. Depending on the planning problem being solved, you can use heuristics, PP/DS optimization, or Detailed Scheduling (DS) functions in the production planning run. In the production planning run, you can execute various planning tasks in several consecutive processing steps using different heuristics or functions. For example, you could first execute procurement planning for products with uncovered product requirements using a product heuristic, and then execute sequence optimization on the relevant bottleneck resources.
The objective of a production planning run is generally to create a feasible production program. The actual planning is normally broken down into several steps, like in the following sample process:
Normal material requirements planning is carried out using either MRP Live in ERP on SAP S/4HANA or on ePP/DS carried out with the SAP_MRP_001 heuristic.
Both are executed infinitely.
- To link the created structure of requirements and receipt elements with each other on multiple levels, a heuristic for creating fixed pegging is used.
- The capacity planning step can be carried out with the optimizer, which, in addition, you can carry out simultaneous sequencing regarding setup times.
- The rest of the components, not relevant for advanced planning, on lower low level are planned in the SAP S/4HANA MRP Live.
In the production planning run, you can define several sequential processing steps in which the system executes various heuristics and functions for the objects specified. You can define which objects are to be processed with which heuristics or functions. The objects must be compatible with the selected heuristic. For example, production planning heuristics can only plan products.
You can execute several heuristics or functions sequentially. Functions such as optimization or scheduling can be carried out within a production planning run. Multiple production planning runs can be performed sequentially for various products, for example. For each processing step, you define the following:
- The heuristic or function to be executed in this step.
- The strategy profile to be used for the heuristic or function. If you opt for the optimization function, you have to enter an optimization profile.
- The objects (for example, 4 = products) for which the heuristics/functions are to be executed.
- If necessary, further selections that can be used to restrict planning to specific objects.
If you set the Planning file entry indicator on the initial screen for the production planning run, you can limit planning to products to which planning-relevant changes have been made (change planning run). If the production planning run is started with the Planning file entry indicator, the only products planned are those for which an MRP-relevant change was made. MRP-relevant changes lead to an entry (indicator) in the planning file. MRP-relevant changes could be newly created sales orders, dependent requirements, or stock changes, but might also be changed to the procurement type in the product master or changes to the operation times in the PDS, and so on.
Combining Multistep Planning Run in PP/DS with MRP Live
There are several opinions to execute a production planning run in SAP S/4HANA with or without PP/DS. To combine both planning philosophies is the challenge of MRP Live. MRP Live can combine both algorithms, MRP in SAP S/4HANA and advanced planning in PP/DS.
For all materials, which are activated for PP/DS using the advanced planning flag in the location product, a planning in PP/DS is executed. For all other products, the planning remains in SAP S/4HANA. MRP Live is able to combine both planning algorithm in one planning run.
This means MRP Live executes the PP/DS planning and the production planning in SAP S/4HANA in parallel with one constraint. During the MRP Live, planning takes the standard heuristic from the Global Parameters and Defaults of the customizing or the heuristic from the location product into account.
In case you are using a planning run with a setup of various steps, this can lead to the following situation: first you are planning your demands using different detailed heuristics. After the PP/DS planning run, an MRP Live should be executed to also plan the non-PP/DS planned materials based on the results of the PP/DS planned materials.
During this planning run in SAP S/4HANA, MRP Live also recalculates the PP/DS products and reschedules these receipts dates and times. This means the following: the results from the detailed planning run are gone. To avoid this, you must exclude these products in the definition of the planning scope, for example, by using the material number as a selection or a different MRP Planner assigned to the PP/DS materials.