You use the Production Planning and Detailed Scheduling (PP/DS) feature:
- To create procurement proposals for in-house production or external procurement to cover product requirement
- To optimize and plan the resource schedule and the order dates/times in detail
You can take the resource and component availability into account here. Above all, PP/DS is used to plan critical products, such as products with long replenishment lead times or products that are produced on bottleneck resources. You can use PP/DS to create executable production plans and:
- Reduce lead times
- Increase on-time delivery performance
- Increase the throughput of products and reduce the stock costs, through better coordination of resources, production and procurement
In previous releases, PP/DS was as part of SAP SCM APO. Now it is fully integrated in SAP S/4HANA. To know more about the difference between standalone PP/DS as a part of PP/DS and PP/DS as a part of SAP S/4HANA, refer to the simplification list provided in SAP Note 2372590.
PP/DS is used for (finite) planning with exact times in the production plant for both in-house production and external procurement. PP/DS covers requirements by generating planned orders to plan in-house production as well as purchase requisitions or schedule lines to plan external procurement.
The advanced planning functions that are available in PP/DS may not be required for all materials. Typically, critical products that are usually manufactured using bottleneck resources are planned in PP/DS while less critical materials that are usually consumption-based purchasing materials are planned with MRP Live.
You must carefully define the choice of materials to be planned in PP/DS. For example, you should plan all products in PP/DS that are produced on the same resources. Otherwise, practical capacity planning may not be achieved.
Planning in PP/DS has a wide range of benefits. Lead times can be reduced by optimizing order sequences. Precise planning enables you to reduce stocks, and simultaneously achieve improved delivery reliability.
Advantages of Planning with PP/DS
- PP/DS plans with exact times up to seconds, even for dependent requirements.
- A wide range of standard heuristics can be used for the flexible design of planning processes, including a bottom-up heuristic for bidirectional planning.
- A multi-level view of material availability and capacity availability (pegging) is possible.
- Enhanced options for capacity planning are available.
- Optimization procedures to minimize setup times, setup costs, scheduling delays, alternative resource selection, and so on, are conducted within Detailed Scheduling (DS).
- Dynamic exception messages (Alerts) are created.
Dependent requirements and orders are created with exact times.
Bidirectional planning: If a planned order has been started in SAP ECC for a component in the past, planning switches to forward scheduling. However, the overlying planned order for the end product is not rescheduled. For example, you can use a bottom-up heuristic to ensure that the planned order for the finished product does not begin until the component has been completed.
You can define resources as finite resources in the resource master. Order operations are only created at these resources if there is sufficient capacity to fulfill the order quantity by the indicated due date. If the available capacity is insufficient, the system searches for a new date by taking the capacity situation into account.
Machine scheduling optimization: Over time, orders having an order sequence that is not optimal may have been generated. Therefore, you can change the sequence and resource assignment of existing orders in the optimization run.
You transfer the planning-relevant data such as master and transaction data (for example, sales orders and stocks) from SAP S/4HANA to PP/DS. You plan the critical products in PP/DS and transfer the planning results to SAP S/4HANA. In SAP S/4HANA, you execute order processing for manufacturing orders and, if necessary, plan the uncritical products. You manage the stocks here too.
The PP/DS master data objects are different from classical PP master data objects in SAP S/4HANA like plant, material, workcenter and routing.
Most of the relevant classical SAP S/4HANA PP master data objects are transferred to the corresponding planning master data objects in PP/DS by setting a simple flag.
PP utilizes background planning runs and interactive work tools, such as the product view with PP heuristics that perform a net requirements calculation and replicate the lot-size procedure. This planning is infinite and does not take into account any overloads on resources that may occur.
DS can then take place using background planning runs or, interactively, using the DS planning board. DS heuristics and the PP/DS optimizer are also provided here as automated help. If DS leads to feasible plans where PP has been fixed in advance, it might be necessary to replan, repeat PP using different constraints, or repeat DS, for instance.
Forecast consumption is a central function in PP/DS and ERP systems. It is an integral part of the PP/DS planning process.
In a very general sense, consumption is the comparison of two order types. One or more order types that represent actual requirements can then use up or consume another order type. More specifically, in PP/DS planned independent requirements are consumed by other order types, such as sales orders, dependent demand, or transfer requirements.
The purpose of consumption is to ensure that requirements are not duplicated in the system and that the most detailed requirements are used. Forecasts and sales orders are for instance both requirements. Since a forecast is less specific than a sales order, it is reduced when other more specific requirements, such as sales orders, exist for the same product. In this way, if both forecasts and sales orders are used to generate receipt elements, for example planned orders, the correct quantity is always generated.
The following are the characteristics of infinite planning: Resources are not checked when a planned order is created. The planned order is created even when there is a capacity overload.
DS heuristics (capacity planning) subsequently produce a feasible production plan. Final optimization of the plan is possible.
If a resource planned with finite planning is already exhausted on the desired date, the system searches for a new date on which the planned order can be created. You use the strategy profile to define how the system has to schedule orders (find slot, conduct infinite planning, and so on).
You define a resource planned with finite planning using the finite resource indicator in the workcenter master. Order operations are created for these resources only when there is sufficient capacity available for the order quantity on the order date.
A strategy profile is maintained in Customizing. In heuristics, planning methods or PP/DS global settings, you define the profile that is to be used to plan planned orders.
If there is insufficient stock or receipt quantities to cover a requirement, the PP run generates a planned order. The PDS is exploded and dependent requirements are created for the assemblies. Planning at the next Bill of Material (BOM) level takes place in the same way. If there is insufficient stock or receipt quantities, planned orders are also created here. These, in turn, may have dependent requirements, and so on.
When the lot size of the planned order has been determined and the PDS has been exploded, the dates of the planned orders are calculated in PP runs. The operation times in the PDS and any goods receipt processing times maintained in the product master are taken into account.
The dependent requirements dates are moved to the dates of operations belonging to the PDS. This allows for operation-specific and on-time material staging.
The system assumes material staging based on the assignment of components to operations in the PDS. The dependent requirements date of the BOM components is set on the production start date of the operations to which they are assigned.
The schedule is displayed graphically in the detailed scheduling planning board.
The planning board is used for interactive planning. For example, the planning board is used for interactive processing of operations to resources and for dealing with alerts. You can call the planning board directly from the PP/DS menu or from order processing. You can choose your own preferred layout for the planning board. For example, you can determine that different charts, such as the resources and order charts, are displayed and specify the field selection and arrangement for the columns in the table section of the chart.
You can map the objects that are displayed in the diagram section of the chart, such as operations and orders (graphical objects), histograms (curves for warehouse stock and resource loads), network views of operations and orders, and the time and pegging relationships between operations and orders.
Integration of PP/DS to Project Manufacturing
It is possible to have project networks scheduled in SAP S/4HANA PP/DS. You can use the following functions to support the process:
- Earliest and latest start and end dates of operations within an order:
These dates/times are displayed in the detailed scheduling planning board in the detail data of operations of an order, and in order processing.
These dates are only determined and displayed if you select the indicator Display Earliest/Latest Operation Dates, which you can find in Customizing under Advanced Planning.
The following figure illustrates how the system calculates the activity dates of the order, taking into account the preceding and succeeding orders that are linked to the order via pegging relationships. The system treats preceding and succeeding orders as fixed.
- Visualization of Relationships in the Detailed Scheduling Planning Board
- Details about the Resource Utilization List:
In the detail view for resource utilization in the resource utilization list, you can also see details about capacity requirements. You can see which proportion of the capacity requirements is made up by planned orders, production orders, and so on. This information is also grouped according to order priority, status of the activity, and order type.
- Hierarchical selection of orders in the detailed scheduling planning board:
In the network, you can select by hierarchy. You can select preceding and succeeding orders individually, or select all preceding and/or succeeding orders that are linked to the order via pegging relationship. You can use the following functions:
- Select all preceding orders
- Select all directly preceding orders
- Select all objects of the order
- Select all directly succeeding orders
- Select all succeeding orders
- Heuristics for project manufacturing and make-to-order manufacturing
- Displaying Network Alerts for Project Orders at Operation Level:
For project orders only, you can see network alerts at operation level in the order view, and not, as before, at order level.
PP/DS Heuristics for Project Orders/Networks
Several PP/DS heuristics support the scheduling of project order/ networks:
- Calculation of the Critical Path (SAP_PMAN_001):
With the heuristic SAP_PMAN_001, you identify operations without a float or with just a small float. The heuristic determines all operations in a multi-level network of orders that have floats (that is, the interval between the latest and the earliest start date) that are equal to zero or that fall below a certain threshold value (defined by you). These operations are regarded as critical. These operations do not have to follow one another. Partially confirmed operations are fixed and therefore are taken into account during scheduling, but are not rescheduled. If you want the system to schedule these operations, you must interrupt these operations – in other words, you must remove the fixing of these operations.
The system calculates the critical path infinitely and in three steps:
- Backward scheduling:
Starting from the end date of the network, the system carries out backward scheduling and determines the "latest start dates" of operations.
- Forward scheduling:
The system then carries out forward scheduling (based on the latest start date from the backward scheduling run) and determines the 'earliest start dates' of operations. The difference between the 'earliest' and the 'latest' position of the operation in the network is called the float. The float is a gross value that does not contain non-working times, for example.
- Critical path:
The system calculates the critical path. If the float of an operation is smaller than the threshold value that you have defined in the heuristic, the operation belongs to the critical path.
- Infinite Backward Scheduling (SAP_PMAN_003):
With the heuristic SAP_PMAN_003, you can backward schedule a network of orders starting from the end date/time. You use this heuristic to achieve a compact network after having reduced planning or process-based minimum intervals or offsets along the critical path. The heuristic adjusts the production plan to the new planning-related minimum intervals and planning-related offsets.
Planning with Project Manufacturing Heuristics:
During planning with planning-related/process-related minimum intervals and offsets, the system behaves as follows:
You can use the project manufacturing heuristics (SAP_PMAN_*) to carry out scheduling taking into account either the planning-related offsets/minimum intervals, or the process-related offsets/minimum intervals.
If you use other heuristics, the system takes into account either the planning-related offset or the process-related offset, depending on which offset was most recently scheduled.
If you select the indicator Use Planning-Related Minimum Intervals in the strategy profile, the system observes the planning-related minimum intervals during infinite and bucket-finite planning. Instead of using process-related minimum intervals, the system plans with the larger planning-related minimum intervals.
If you use the project manufacturing heuristics (SAP_PMAN_*), you should select an order or operation at the highest MRP level, so that the system completely schedules the relevant network of orders.
You should note that the project manufacturing heuristics (SAP_PMAN*) always schedule planned orders within the order validity, in other words, during scheduling no new source of supply is assigned, nor is a new explosion carried out.
