APO_Note1

8/12/2019 APO_Note1

http://slidepdf.com/reader/full/aponote1 1/45

Thursday, January 5, 2012

Note 481906 - SNP - PP/DS integration

Source:https://websmp230.sap-

ag.de/sap%28bD1lbiZjPTAwMQ==%29/bc/bsp/spn/sapnotes/index2.htm?numm=481906

SummarySymptom

The following questions arise in connection with the integration of SupplyNetwork Planning (SNP) and Production Planning and Detailed Scheduling

(PP/DS):

What are the differences between SNP plans and PP/DS plans?

What are mixed resources?

How do I set up mixed resources?

I work with periodic lots in the PP/DS heuristic. If part of a period isoutside the PP/DS horizon, the PP/DS order nevertheless covers the

requirements in the second half of the period. This means thatrequirements outside the PP/DS horizon are covered by PP/DS.

Why? Does this not affect the separation of SNP and PP/DS?

What is the function of the heuristic switch for taking into accountshortages outside the production horizon?

SNP plans a stock build-up. This stock build-up is destroyed byPP/DS. How can I prevent this?

Is there a heuristic that considers the requirements only up to thehorizon end in the planning?

What is the role of mixed resources?

I use mixed resources. After the system converts an SNP plannedorder to a PP/DS planned order, the capacity requirements in the

SNP capacity view differ from the capacity requirements before theconversion. Why?

What is modeled using the lot-size intervals in the SNP productionprocess model (PPM) and in the PP/DS PPM?

What do I need to take into account regarding lot sizes whenconverting from SNP to PP/DS?

http://scmgmt.blogspot.in/2012/01/note-481906-snp-ppds-integration.html



8/12/2019 APO_Note1


Which planning area is relevant for the SNP->PP/DS orderconversion?

What strategy profile is to be used for the SNP->PP/DS orderconversion?

Packaging SNP orders during the SNP order conversion

Other terms SNP-PP/DS integration, documentation, FAQ, production horizon, PP/DS

horizon, SNP->PP/DSReason and Prerequisites

Comparing SNP with PP/DS: SNP

The Role Of SNP=================

SNP planning makes the decisions on tactical planning and source ofsupply determination. The strengths of SNP planning are: The selection ofthe source of supply taking into account the costs, and the determination

of the approximate production date taking into account both theprocurement costs and the storage costs. The result of the SNP planningis the answer to "What is produced, where and when?". The answer to"when" cannot be more precise than a planning period, and it does not

take the sequence-dependent setup activity into account.

The SNP Optimizer===================

The SNP optimizer performs cost-based optimization. The SNP optimizercreates a production plan in a way so that an objective function is as closeto its minimum value as possible. The objective function is the weighted

total of the following costs:

Production costs, procurement costs, storage costs, andtransportation costs

Penalty costs for non-coverage or delayed coverage of therequirement or the safety stock

Costs for increasing the capacity (with regard to the production, thestorage, the shipment, and so on)

The SNP optimizer is therefore able to make the following decisions inparticular:

8/12/2019 APO_Note1


A product is subject to seasonal fluctuations. Is it cheaper to buildup a warehouse stock in low season (storage costs) or to use anexpensive source (in-house production or external procurement)?

You can either procure a product externally or produce it in-house.

In the current requirement situation, is it cheaper to procure aproduct externally (in this case, the resource is available for the

production of another product) or to produce it in-house?

A product is in stock in one plant, but it is required in another plant.Is it more favorable to transfer the product (as a result, a future

requirement may have to be covered differently in this plant) or toproduce it again in-house?

A resource can produce a quantity A of products. Different costs are

incurred when these products are produced. Another resource canproduce a different quantity B of products. The quantities A and Bhave an intersection. On which resource are the products from the

quantities A and B produced at the lowest cost?

The SNP optimizer determines the following:

The production quantities, the procurement quantities, the stocktransfer quantities for each product and period

The selection of the resources and the plans for the production

The selection of the plants, the warehouses, the suppliers, and thetransportation lanes

The SNP optimizer works on the basis of periods. The sequence of orderswithin a planning period is not defined. This has the following

consequences:

The SNP optimizer can consider only a constant setup time.Sequence-dependent setup times or sequence-dependent setup

costs are not supported.

It can only provide a rough model for the material flow. In principle,a material flow occurs only at the period boundaries.

Setup In The SNP Optimization===============================

SNP planning is period-based planning. SNP planning determines theproduction quantities for each period; it does not determine the sequence

8/12/2019 APO_Note1


of production orders. Therefore, SNP planning cannot take into accountthe exact effort required for the setup.

Usually, setups in SNP optimization are only taken into account by a setupallowance. The attributable capacity of a resource available in SNP is

reduced by the loss factor. This means that a part of the capacity is kept

free for the setup. You can set the loss factor for mixed resources in themaster data of the resource.

Using the modeling option for fixed resource consumptions in SNP, theSNP optimizer supports a simple lot size planning, which may also be

performed across periods for APO Release 3.1. Lot size planning reducessetup costs by summarizing the orders for large lots. With cross-period lotsize planning (APO Release 3.1), the setup statuses of the previous periodare taken into account when a product is produced in the current period

with the same plan. This lot size planning is used in industries wheresetup operations greatly influence the production costs. If setups play a

major role, you should try to ensure that the setups are already takeninto account in SNP. SNP then generates plans that represent a reliable

template for planning in PP/DS.

Material Flow In SNP Optimization=========================================

The period factor or bucket offset controls the modeling of the materialflow in SNP. If the period factor is high, you can often produce two or

more production levels in one bucket. The lead times on severalproduction levels become shorter. However, the result may be too

optimistic. If you wish to err on the side of caution, you must work with aperiod factor of zero, but this is at the expense of the lead time.

The period factor in the product master applies only to the SNP heuristic.The same function can be applied in SNP optimization using the bucketoffset in the SNP optimization profile and in the PPMs and transportation

lanes.

Model Size And Complexity===========================

Due to the runtime and memory requirements of SNP optimization, we

must also think about the model size and the model complexity. Creatingan SNP production plan is an NP-completeness problem. IT theory hastaught us that there is no known algorithm to guarantee finding anoptimal solution for the problem in polynomial runtime. For more

information on NP-completeness problems, we recommend that you readthe following book by Michael R. Garey and David S. Johnson:"Computers and Intractability: A Guide to the Theory of NP-

Completeness".In the case of SNP optimization, a distinction must always be made

between purely continuous models and models known as discrete models.If fixed lot sizes, minimum lots, or piecewise linear cost functions are tobe taken into account, you will require a discrete model. In this case, the

8/12/2019 APO_Note1


system must perform a mixed integral optimization.The continuous models are primarily restricted because of the memoryrequired. However, the required runtime of purely continuous models islinearly dependent on the model size and is generally non-critical as a

result.

On the other hand, the solution of discrete models using a mixed integraloptimization can be considerably more complicated. It is generally not

possible to guarantee the global optimum under realistic CPU timetargets. Instead, permitted and high-quality solutions must be found with

acceptable runtimes. The runtime and memory requirement of SNPoptimization depends on the number of the variables. The number of

variables is therefore restricted. You require a variable for eachproduction quantity or procurement quantity that you want to determineusing SNP optimization. In other words, you require a variable for eachlocation product for each planning period. The practical upper limit is

approximately two (2) million continuous variables or 100,000 discreetvariables.

The following is an example of a continuous model:7,000 products * 5 locations * 52 weeks = 1,820,000.

This type of continuous model already belongs to the large optimizationmodels. This means that we require 4GB RAM for this continuous model.

If the problem is too large or too complex, it may be simplified as follows:

We are planning in large periods rather than small periods (monthsinstead of weeks).

We consider fixed order quantities, minimum lot sizes, and so ononly where necessary.

Non-critical products and resources are not included in the planning.

You can use decomposition procedures to divide the optimization probleminto several subproblems that are optimized separately. You can thereforeoptimize larger models than those listed above. Contact your consultant

for more information.

Restricting the model size is a considerable incentive for hierarchicalproduction planning. In SNP planning, you often have to work onaggregated data in order to reduce the number of variables.

Nevertheless, you should determine detailed production plans at a laterstage. The detailed production plans are then created using PP/DS.

Advantages Of SNP Optimization=============================

Optimizing procurement costs while taking into account alternativesources of supply

Taking capacities into account

8/12/2019 APO_Note1


Distributing the production over several periods (during seasonalfluctuations, for example) while taking storage costs into account

Disadvantages Of The SNP Optimizer

=============================The SNP optimizer has the following restrictions:

It does not have a sequence-dependent setup activity.

Planning takes places in planning periods (buckets). The ordersequence is not defined within a planning period.

The number of variables is restricted. It often happens thatoptimization can only consider some products or it has to work with

large periods (usually months).

Make-to-order production is not supported.

Configurable products are not supported.

The SNP plan does not permit different component validities. Thismust be modeled using several SNP plans. For more information,

see Note 513868.

It can only provide a rough model for the material flow. Thisbasically occurs only at the period boundaries.

The SNP optimizer is therefore particularly suited to medium to long-termplanning. You generally have to use the SNP - PP/DS order conversion to

convert the result of the SNP optimizer to PP/DS orders. One of theactions you can then perform in PP/DS planning is to determine the exact

sequence for production orders.

The SNP Production Horizon============================

SNP does not create any orders within the SNP production horizon. TheSNP production horizon can therefore be used to divide the

responsibilities for planning among Supply Network Planning (the order isoutside the SNP production horizon) and Production Planning and Detailed

Scheduling (the order is within the SNP production horizon).

SNP Plans==========

An SNP plan is the basis for planning in-house production in SNP and is

stored in APO as SNP PPM or SNP PDS. SNP planning is primarily designedto provide a plan outlining the resource and component requirements in

8/12/2019 APO_Note1


advance, and it does not aim to provide an exact model of all technicaloptions. SNP plans are therefore simpler than PP/DS plans. Mode linkage,cover, minimum and maximum intervals of relationships, and so on are

not important in SNP planning and therefore cannot be maintained in theSNP PPM. Alternative modes must be modeled in SNP as alternative PPMs

or alternative SNP PDSs. An SNP plan refers to planning in planningperiods. The length of an activity cannot be less than a day. SNP permits"day" as the smallest planning period. You can therefore plan accuratelyto one day at the most. In contrast, PP/DS permits planning to the exact

second.

Validity Of SNP Plans==========================

Usually, the lot-size intervals of an SNP plan differ from the lot-sizeintervals of the corresponding PP/DS plan. Typically, the lot-size interval

of the SNP plan should correspond to the maximum quantity that can beproduced in a planning period, while the lot-size interval of the PP/DS

plan should correspond to the maximum order size. If several orders canbe produced in a planning period, the lot-size interval of the SNP plan isusually larger than the lot-size interval of the PP/DS plan. If productiontakes longer than an SNP planning period, the lot-size interval may be

smaller in the SNP plan than in the corresponding PP/DS plan.

Comparing SNP with PP/DS: PP/DS

The Role Of PP/DS==================

The strengths of PP/DS planning are its consideration of sequence-dependent setup activities and restrictions that apply to the generation ofproduction orders that can be produced: complete bills of material (BOMs)

and routings, inclusion of change statuses and configuration. It alsoguarantees feasibility with planning that is exact to the second, and so

on.

In general, lot sizes cannot be optimized independently of the sequence of

the production orders. Lot size optimization is therefore regarded as beinga PP/DS task. However, since you quickly encounter calculation limits,PP/DS offers only limited help during lot size optimization.

The PP/DS Optimizer====================

Up to an including SCM 5.1, the PP/DS optimizer cannot create any neworders, but it optimizes the date and time of production and resource

assignment of operations with regard to the following criteria:

Total lead time

8/12/2019 APO_Note1


Setup times

Setup costs

Delay costs

Mode costs

These criteria form part of the objective function. The objective function isthe weighted total of the criteria mentioned above. Optimization

determines a production plan in which the required result, for example,the minimum setup times or sequence optimization, is achieved as far as

possible. For this, the system varies the start times and the resourceassignments of the operations. The system then uses the set objective

function to assess the production plans created in this way. Theproduction plan that has the minimum value for the objective function is

the result of the optimization.Read Note 712066 for further and more recent information about the

PP/DS optimizer and restrictions for the PP/DS optimizer.

The PP/DS Horizon==================

PP/DS planning is carried out within the PP/DS horizon. PP/DS planningusually does not create orders outside the PP/DS horizon.

The following exceptions exist:

o You can manually create PP/DS orders outside the PP/DShorizon.

o You can use transaction /SAPAPO/SNP2PPDS to convert SNPorders to PP/DS orders. In this case, all SNP orders within a

PP/DS horizon and an offset are selected.

o The PP/DS optimizer can delay PP/DS planned orders from thePP/DS horizon if insufficient capacities are available within the

PP/DS horizon.

o In the case of finite scheduling, the scheduler in the liveCachecan delay PP/DS planned orders from the PP/DS horizon if

insufficient capacities are available within the PP/DS horizon.

In APO Release 3.0, the PP/DS horizon is identical to the productionhorizon. In APO Release 3.1, the PP/DS horizon and the SNP productionhorizon may differ. If the PP/DS horizon is initial, the SNP production

horizon is used as the PP/DS horizon. In this case, there is no overlapbetween the two horizons. If the PP/DS horizon is shorter than the SNP

8/12/2019 APO_Note1


production horizon, the PP/DS horizon is extended to the SNP productionhorizon. The time axis does not have any area that is not planned by

either PP/DS or SNP. However, the PP/DS horizon can also be longer thanthe SNP production horizon. In this case, there is an area on the time axis

that is planned jointly by SNP and PP/DS.

PP/DS Plans============

A PP/DS plan provides the basis for planning in-house production inPP/DS. PP/DS plans are stored either as PP/DS PDSs or as PP/DS PPMs. InPP/DS, the production process is described using activities that are linked

through relationships. Several logically related activities form anoperation. In discrete manufacturing, an operation is generally composed

of setup activities and processes. In process industries, on the otherhand, operations are often more complex. An operation in the process

industry can therefore consist of activities such as mixing, stirring,heating, cooling and cleaning. The activities of one operation must not be

interrupted by the activities of another operation. The switch forcontinuous reservation of the resource is set in the PPM. This feature is

called "Cover". In the PDS, the Cover feature for the activities in anoperation is always set automatically.

The activities of a PP/DS plan can be carried out on alternative resources.These are defined as a mode in the plan. Each mode can have a differentduration. If an activity is carried out on a certain alternative resource, this

can mean that subsequent activities must also be carried out on

compatible resources. This is known as mode linkage. The simplest caseof mode linkage is where setups and processes have to be executed on

the same resource.You require both components and resources to execute an activity. The

component consumption of each activity is also defined in the PP/DS plan.In APO, you can use PP/DS PPMs, iPPE models, or PDSs generated from

R/3, as PP/DS plans. The PP/DS PPM or a PDS generated from R/3 iseither a combination of an R/3 BOM and an R/3 routing, or a combination

of an R/3 BOM and an R/3 recipe.

Do We Require Modes In PP/DS?============================SNP planning does not know the mode concept from PP/DS. The

integration of PP/DS plans with SNP plans results in additional work ifalternative modes are used in PP/DS. The amount of work involved can be

reduced by not using alternative modes in PP/DS. However, thedisadvantages of not using alternative modes in PP/DS are as follows:

The PP/DS optimizer can independently select the alternative modethat allows the best production date. If no alternative modes are

used in PP/DS, the PP/DS optimizer is unable to carry out aresource selection.

8/12/2019 APO_Note1


With forward scheduling, scheduling of planned orders in theliveCache selects (upon request) the mode that allows the earliest

production date. With backward scheduling, scheduling selects(upon request) the mode that allows the latest production date.

In the graphical planning table, you can use drag and drop toreschedule an operation from one mode to an alternative mode. Allof the alternative modes of an operation are highlighted in color. If

no alternative modes are used in PP/DS, you cannot selectresources using drag and drop in the graphical planning table.

Instead, you must navigate to the order processing for the selectedoperation and change the source of supply for the order there.

Validity Of PP/DS Plans

============================Usually, the lot-size intervals of an SNP plan differ from the lot-size

intervals of the corresponding PP/DS plan. Typically, the lot-size intervalof the SNP plan should correspond to the maximum quantity that can be

produced in a planning period, while the lot-size interval of the PP/DSplan should correspond to the maximum order size. The maximum

quantity that can be produced per order is usually defined by physicalconstraints (for example, the boiler size). A PP/DS planned order that is

outside the valid lot-size interval cannot be produced.

SNP and PP/DS: Shared view of the planning situation

SNP is used to determine an optimal sourcing for the planning. The plancreated by SNP must be detailed at a later stage. The aspects of planning

that were not considered in SNP must be taken into account.For example:

The sequence-dependent setup activities

The resource selection

The exact production time within the planning period and theresulting sequence of operations on the resource

The addition of components and capacity requirements that werenot planned in SNP; this is to keep the model easy to handle.

PP/DS is used for these. If you want to add details to the SNP productionplan or execute it, you must transfer the SNP production plan to a PP/DS

production plan.

8/12/2019 APO_Note1


If SNP planning and PP/DS planning are carried out in a shared planningversion, this results in several interfaces between the two plans:

SNP planning must regard the results of PP/DS planning as fixedreceipt or requirement elements.

SNP planning must take into account the capacity consumption ofPP/DS orders on mixed resources. If required, SNP planning takes

into account the setup statuses on single mixed resources thatresult from PP/DS orders.

The SNP production horizon of a product may be shorter than thePP/DS horizon. In this case, this leads to a product time interval

that can be planned by both SNP and PP/DS.

Even though two products have disjunct SNP and PP/DS horizons,both products are produced on the same resource. If the PP/DS

horizons for these two products differ, a time interval that is jointlyplanned by SNP and PP/DS is created on the resource.

Different production levels potentially have different PP/DShorizons. If the offset of the PP/DS horizons does not correspond tothe negative lead-time offset, a dependent requirement from SNP

planning must be covered by a PP/DS receipt element or vice versa.

A controlled transfer to the PP/DS planned orders must take placefor the planned orders created by SNP planning.

Fixing PP/DS Planned Orders In SNP Planning=============================================

=======PP/DS receipt elements can be displayed for SNP, but these elements arefixed. The stocks and PP/DS receipt elements are read and offset against

the existing requirements as part of an SNP heuristic or the SNPoptimization. During this, it is irrelevant whether the requirements lie

inside or outside the production horizon. As a result, requirements outsidethe production horizon may also be covered by receipt elements withinthe production horizon. In this case, SNP must create new SNP receiptelements only for the remaining uncovered requirements. SNP cannot

change PP/DS receipt elements. SNP handles PP/DS receipt elements inthe same way as it handles stocks. SNP planning is therefore unable to

adjust PP/DS planned orders to a changed requirement situation.

PP/DS planned orders are fixed for SNP planning because they areprocessed using functions that SNP planning is unable to understand; for

example, exact scheduling or the explosion of PP/DS plans. Even ifunnecessary PP/DS orders are outside the PP/DS horizon, SNP planning

8/12/2019 APO_Note1


cannot delete these orders.

Pegging=======

The system creates pegging relationships between the product receipts

and the product requirements regardless of whether the product receiptsor the requirements involve SNP orders or PP/DS orders. This solves the

following problems:

The PP/DS horizon for a component is longer than the PP/DShorizon for the superior assembly. This will result in a situationwhere an SNP planned order is created for the assembly while

PP/DS receipt elements already exist for the components. An SNPplanned order can cover its dependent requirements from PP/DS

receipt elements.

A fixed lot size or a minimum lot size is set for a product. Therequirement within the PP/DS horizon is smaller than the fixed lot

size. This requirement is covered by a PP/DS receipt element.However, this receipt element is not fully required within the PP/DShorizon. The system uses the surplus to cover requirements outside

the PP/DS horizon.

The PP/DS horizon for an end product is longer than the PP/DShorizon for a component. A PP/DS planned order is created for the

end product. The dependent requirement for this planned order iscovered by an SNP receipt element during the next SNP planning for

the component.

Mixed Resources===============

Mixed resources allow SNP and PP/DS to have a shared view of theresource schedule. The capacity commitment from PP/DS orders is also

displayed for SNP on mixed resources. For this, the PP/DS capacity

commitment is converted to a bucket resource reservation.Single-mixed resources correspond to single activity resources in thedetailed scheduling. Multimixed resources correspond to multi-activity

resources in PP/DS planning. In Supply Network Planning, mixedresources behave in the same way as normal bucket resources.

Mixed resources can serve their purpose only if the capacity requirementsfor the PP/DS planned order are approximately the same as the capacity

requirements for the SNP planned order.For PP/DS planned orders, a capacity requirement on the bucket resourceis calculated from the capacity requirement on the single resource. As a

result, PP/DS capacity requirements are also displayed in SNP. Finite SNPplanning can create new planned orders within the SNP horizon ifsufficient capacity is still available for SNP despite the capacity

8/12/2019 APO_Note1


commitment caused by PP/DS planned orders. Since PP/DS plannedorders are fixed for SNP planning, it is sufficient to simply reduce thecapacity available for SNP by the portion consumed by PP/DS planned

orders.As of APO Release 3.1, single-mixed resources can be used to model

block capacities for block planning in characteristics-dependent planning(CDP). If a mixed resource is used for block planning, it can no longer be

used in SNP.

Integration Master Data: Resources

How Do I Set A Mixed Resource?=======================================

In APO, you cannot convert a single-activity resource to a single-mixedresource. You cannot convert a multi-activity resource to a multimixed

resource either. In this case, you must delete the old resource and createa new resource.

If the resources are transferred from the R/3 system, the resource typemust be changed in the inbound interface of the APO system. (For more

information, see Note 329733).If the user exit for resources is used to create mixed resources from the

R/3 system, the user exits for the objects that use the resources(especially PPM) must be adjusted. (For more information, see Note

321474).

Problem: Different Capacity Requirements In SNP And PP/DS=============================================

==========The bucket requirements of a mixed resource are calculated in the PP/DS

planned order only so that SNP planning obtains an accurate pictureabout the reservation of the resource from the SNP view. SNP planningcannot plan the resource correctly if the capacity requirements differ.

Cause=======

The system explodes the plan again when an SNP planned order isconverted to a PP/DS planned order. During this, the capacityconsumptions are determined again. If the bucket consumption in thePP/DS plan differs from the bucket consumption in the SNP plan, the

capacity consumption of the orders generated from the plans also differ.

Solution======

Ensure that the bucket consumption in the PP/DS plan is identical to thebucket consumption in the SNP plan. You will find the bucket

consumptions in the PP/DS PPM and SNP PPM as follows: There is anavigation tree in the upper left part of the PPM maintenance screen.

8/12/2019 APO_Note1


Open the operation and open the activity. Then open the mode anddouble-click the resource. If you use the PDS, you can use transaction

/SAPAPO/CURTO_SIMU to display the bucket consumption.In addition, the bucket consumptions in the PP/DS plan should correspond

to the capacity requirements in PP/DS.

Example 1==========

The available bucket capacity for our resource can be defined as follows:Capacity=1,000 pieces per week. The resource is a single-activity

resource that works 40 hours per week. An order of 100 pieces requiresfour hours in PP/DS and reserves 100 pieces of the available bucket

capacity. As a result, the bucket consumption is 100 pieces. You definethe variable duration of four hours/100 pieces in the mode of the PPM.You define the variable bucket consumption in the resource chart of the

PPM.

Example 2==========

The comparison of SNP capacity consumptions and PP/DS capacityconsumptions becomes especially intuitive if the available bucket capacity

(and therefore, the bucket consumption) is defined in a time unit. Theavailable bucket capacity can be defined as 40 hours per week. The

resource is a single-activity resource that works 40 hours per week. Anorder of 100 pieces requires four hours in PP/DS and reserves four hours

of the available bucket capacity. In this case, the bucket consumption isfour hours. You define the variable duration of four hours/100 pieces in

the mode of the PPM. You define the variable bucket consumption of fourhours in the resource chart of the PPM. This seems to be an unnecessary

duplicate entry. However, as example 1 shows, this is not the casebecause the dimension of the bucket consumption does not have to be a

time unit.

Connection Between The Duration And Capacity Consumption=============================================

=========As the above example shows, the durations in the mode and the bucketconsumption must be consistently defined in the PP/DS plan. If this is notthe case, incorrect bucket consumptions are calculated for PP/DS plannedorders. In the SNP plan, there is no connection between the duration andthe bucket consumption. The reason for this is the different scheduling in

SNP and PP/DS. The duration in the mode of a PP/DS plan basicallydescribes the pure production time. The queue times between the

activities result from the resource availability or the relationships. On theother hand, the lead time including the queue times is contained in themode of an SNP plan. As a result, there is no direct connection between

the duration and the bucket requirement in SNP.

8/12/2019 APO_Note1


Fixed Capacity Consumptions

=========================Fixed capacity consumptions are usually used to roughly model setupactivities. Setup activities are required between orders that produce

different products. SNP does not perform order-specific planning. Instead,the SNP plan acts as a form of data storage. SNP actually plans quantitiesfor each time interval (bucket). Therefore, fixed capacity consumptionsmust be dealt with carefully. This applies in particular as of APO Release3.1. As of APO Release 3.1, you can split the quantities planned by SNP

during the conversion from SNP to PP/DS (according to the fixed ormaximum lot size in the product master or the lot-size intervals in PPM).

The fixed bucket requirement in PP/DS multiplies as a result of thesesplits. As a result, the differences between the SNP capacity consumption

and PP/DS capacity consumption increase.

Available Capacity In SNP And PP/DS======================================

If you have mixed resources, you can calculate the available bucketcapacity from the continuous available capacity. However, you must bearin mind that part of the capacity in continuous PP/DS planning is requiredfor the setup activity. As a result, the bucket capacity is generally a little

smaller than the continuous capacity. The loss factor in the resourcemaintenance is available for this.

The loss factor must first be defined at random. The bucket capacity

determined in this way therefore does not correspond exactly to thecontinuous capacity of the mixed resource. As a result, it is not

guaranteed that a finite SNP plan created using the SNP optimizer, forexample, can also be converted to a finite PP/DS plan.

You can check the accuracy of the bucket capacities only by analyzing theresults of PP/DS planning and comparing them with SNP planning. If thePP/DS planned orders generate overloads on the continuous capacities(and these did not exist in SNP planning), the setup sequence is either

poor or the bucket capacity is too high. If there is sufficient unusedcapacity in the PP/DS (which is not visible in SNP), we can assume that

the bucket capacity is too low.Even if this type of capacity control is considered to be important if theoverall process is to work over a long period of time, we advise against

having excessive accuracy requirements. With sequence-dependent setupactivities, the capacity requirements on the continuous resource

constantly change every time the sequence of production orders changes.The bucket capacities should not be changed every time for SNP. Capacity

overloads and underloads of 10% are certainly tolerable.

Master data integration: PPM

You can either create SNP PPMs manually, or you can create them from

8/12/2019 APO_Note1


PP/DS PPMs using a generation report. The integration of SNP planningand PP/DS planning requires the following:

SNP master data and PP/DS master data describe the same process(of course while considering the different detailing requirements).

It is possible to establish a relationship between the SNP masterdata and the PP/DS master data. This type of relationship can beused during the conversion of SNP planning to PP/DS planning so

that PP/DS planning uses the same sources of supply and resourcesthat SNP planning used.

SNP PPM and the corresponding PP/DS PPM can only claim to describe thesame process if the following conditions are met:

The lot-size intervals of SNP PPMs and PP/DS PPMs are defineddifferently. The lot-size interval in the SNP PPM describes the

quantity that can be produced in a planning period. The lot-sizeinterval in the PP/DS PPM describes the lot-size interval permittedfor a single production lot. These two lot-size intervals must be

converted correctly.

The temporal validity intervals of the SNP PPM and PP/DS PPM areidentical.

The component requirement quantities are identical.

The operations to which the component requirements in the SNPPPM are assigned correspond to the operations in the PP/DS PPMwith the same component requirements. Example: A PP/DS PPM

operation lasts several SNP planning periods. Several operations arecreated for the SNP PPM. The component requirement in the SNP

PPM must be assigned to the first of these operations.

There is an SNP PPM for each of the most important modes used inPP/DS.

The use of mixed resources is a prerequisite for the integrated SNPPP/DS planning. The bucket consumption in SNP must correspond to

the PP/DS capacity consumption.

The mode duration in the SNP PPM must be calculated correctly.

The best way of meeting these requirements is to use the SNP PPM

generation from PP/DS PPMs. Otherwise, you must ensure that both PPMsdescribe the same processes from an organizational point of view.

8/12/2019 APO_Note1


Generated SNP PPMs===================

SNP PPMs can be generated from PP/DS PPMs. During this, the bucket

consumption of the SNP PPM is determined from the mode durations ofthe PP/DS PPM. We can therefore assume that the available bucket

capacity of the resource has the "time" dimension.In Release 3.0, the variable SNP bucket consumption consists of the

variable bucket consumption and the fixed bucket consumption of thePP/DS PPM. When determining the variable SNP bucket consumption, thevariable consumptions of the output product and the maximum lot size of

the PP/DS PPM are also taken into account. The fixed SNP bucketconsumption is not supported in Release 3.0. The fixed duration in theSNP PPM is determined from the duration of an SNP planned order for a

bucket size. However, a user can use a user exit to maintain the bucketconsumptions and the duration in SNP PPM. In this case, the user is

responsible for the consistent maintenance of the bucket consumptionwithin the PP/DS PPM.

Generating The SNP PPM=====================================

Refer to Notes 516260 and 323884.

Determining The Capacity Requirement

=================================In addition to defining the duration, you must also define the bucketconsumption for a mode when maintaining a PP/DS PPM with a mixedresource. This bucket consumption is transferred to the SNP PPM as acapacity consumption. The bucket consumption does not have to be

defined in the "time" dimension. However, the conversion is especiallysimple if the bucket consumption has the "time" dimension. The PP/DS

mode duration must be the same as the bucket consumption.

You are not permitted to maintain a variable duration and a variable

capacity consumption in the PP/DS if you have multimixed resources.Both capacity requirement dimensions would depend on the quantity. Thiswould lead to a quadratic dependence on the quantity for the bucket

consumption. This cannot be modeled in the SNP PPM.

Mapping Alternative Modes=================================

The generation report for SNP PPMs enables you to generate a specificnumber of SNP PPMs from different mode combinations contained in a

PP/DS plan (SNP PPM generation with a lot size margin). The number ofSNP PPMs depends on the number of activities and alternative modes of

the PP/DS PPM.

8/12/2019 APO_Note1


In turn, SNP PPM generation without lot size margins means that exactlyone SNP PPM is generated from a PP/DS PPM for a single lot size and a

mode combination.

Determining The Mode Durations===========================

SNP planning only roughly considers the durations of operations oractivities. Only bucket resources are reserved in SNP. This does notdepend on the duration of an activity. If, however, the SNP plan hasseveral operations, the resources should be reserved for the correctplanning periods. If the first operation of an order lasts longer than a

planning period, the second operation must be scheduled in a planningperiod at a later stage. This shift is calculated using the mode durations in

the SNP plan. The SNP PPM mode durations differ from the PP/DS PPM

mode durations in the following aspects:

The purpose of the mode duration is different. In the PP/DS PPM,the mode duration is used to determine the exact duration of anactivity. In the SNP PPM, the mode duration is used to determine

the planning period in which the resource is reserved.

A lower degree of accuracy is required when you use the modeduration in SNP. The mode duration in SNP therefore cannot be

maintained as a quantity-dependent mode duration either.

The mode durations in the SNP PPM consider both the modedurations in the PP/DS PPM as well as the minimum intervals in the

relationships in the PP/DS PPM.

When generating without a lot size margin, the fixed duration iscalculated as follows:

For each day that is started and that requires an activity, the fixedduration is increased by one day.

When generating with a lot size margin, the system bundles themaximum number of activities that fit in a bucket (these may be alloperations if you have a monthly bucket). The fixed duration of the modeis then set to one day. The bucket consumptions result from the durations

of the corresponding mode.The logic is as follows: During the SNP PPM generation without a lot sizemargin, a new operation is generated if the primary resource changesfrom one bucket to another. A new activity is generated if a secondary

resource or a material changes.During the generation with a lot size margin, the system merges as manyPPDS activities for an SNP activity as the bucket specification allows. Thismeans: If weekly buckets are used during the generation, a much largernumber of activities fit into a bucket (and are therefore merged for the

8/12/2019 APO_Note1


SNP activity) than if daily buckets were used for the SNP PPM generation.

Determining The Component Quantities=================================

The following applies to SNP PPM generation without a lot size margin:

The variable consumptions from the PP/DS PPM are multiplied by the lotsize from the initial screen for the SNP PPM generation and they are

added to the fixed consumption quantity. The result is transferred to theSNP PPM as a variable quantity. The SNP PPM generation without a lot

size margin cannot represent a fixed material consumption.

Linking SNP PPMs With PP/DS PPMs========================================

The SNP plan can be linked to a PP/DS plan. This means that the systemdoes not find any random PP/DS sources of supply when SNP orders are

converted to PP/DS orders, but it creates the PP/DS orders using thePP/DS PPM that is linked to the SNP PPM.

Manually created SNP plans (PPMs) may also be linked to existing PP/DSplans (PPMs). In this case, however, the user must ensure that the

manual maintenance is a logical representation and creates a correctrelationship between the two plans (PPMs).

Quantity Split During Conversion==============================

The conversion from SNP to PP/DS also entails a change in the planningsemantics from the quantities per planning period that are planned in SNP

to orders. You cannot expect lot sizes to be transferred 1:1 during thischange. With APO Release 3.1, you can therefore split the lot size duringthe conversion. If several fixed lots or lots with a maximum quantity areproduced in an SNP planning period, the split can be performed by noting

the maximum quantities from the product master or the maximumquantities of the lot size intervals in the PP/DS PPM. The conversion

creates several smaller orders with suitable lot sizes.

Selecting A Different PP/DS PPM=============================If you want the lot sizes to be retained (for example, if we use weekly

planning periods in SNP, we also have weekly lot sizes in PP/DS), we cansearch for a suitable PP/DS PPM during the conversion. This is the case if

you do not set the "Use SNP sources of supply" switch on the initialscreen of the conversion report.

PDS Master Data Integration

The SNP PDS is not generated from a PP/DS PDS; instead, it is generateddirectly from R/3 or from an iPPE. This has the following advantages:

8/12/2019 APO_Note1


The master data generated from R/3 can be used directly in SNPwithout having to go through PP/DS first.

The transfer of data changes is simpler.

In the production version, you can use different routings for PP/DSand SNP.

Although these advantages exist, there are also some disadvantages:

The mode durations must be determined in the BAdI.

In the standard system, you cannot create alternative SNP PDSs fordifferent mode combinations.

Determining The Capacity Requirement=================================

During the transfer from R/3 to SCM, the capacity requirements of theSNP PDSs are determined by the default implementation of the BAdI

/SAPAPO/CURTO_SNP as follows: If the bucket resource has the "time"dimension, the capacity requirement is copied from the duration of the

R/3 operation. If you have different dimensions for the available capacityfor the bucket resource, the BAdI must be implemented differently, or you

must maintain the capacity requirements manually in R/3. This option isavailable as of SCM Release 5.0. It is provided by transactionPDS_MAINT.

Determining Mode Durations==========================

SNP planning only roughly considers the durations of operations oractivities. Only bucket resources are reserved in SNP. This does notdepend on the duration of an activity. If, however, the SNP plan hasseveral operations, the resources should be reserved for the correctplanning periods. If the first operation of an order lasts longer than a

planning period, the second operation must be scheduled in a planningperiod at a later stage. This shift is calculated using the mode durations in

the SNP plan. The required mode durations in SNP PDS must thereforediffer from the mode durations in PP/DS PDS as follows:

The purpose of the mode duration is different. In PP/DS PDS, themode duration is used to determine the exact duration of an

activity. In SNP PDS, the mode duration is used to determine theplanning period in which the resource is reserved.

A lower degree of accuracy is required when you use the modeduration in SNP.

8/12/2019 APO_Note1


The mode durations in SNP PDS take into account both the modedurations in PP/DS PDS and the minimum intervals in the

relationships in PP/DS PDS.

As of SCM Release 5.0, you can maintain the SNP mode durations in R/3manually using transaction PDS_MAINT. In lower releases, the mode

durations of SNP PDSs can be changed only using a BAdI. To do this, useone of the following BAdIs:

/SAPAPO/CURTO_SNP method CIF_IMPORT in APO (change the fieldDUR2 in the table CT_MODES). Make sure that you copy thedetermination for the capacity requirements from the default

implementation if you create your own implementation of this BAdI.

CUSLNTRTO_ADDIN method CHANGE_CIF_STRUCTURES in R/3(change the field DUR2 in the table CT_MODES)

Transferring SNP planning to the PP/DS production plan

The result of the SNP optimizer provides a plan that is finite at planningperiod level. However, overloads may still occur within the planningperiods and for sequence-dependent setup activities. These must be

corrected in PP/DS planning.

To plan the result in PP/DS planning in detail, the SNP optimization resultmust be transferred to a PP/DS production plan. Often, only the mostimportant components are planned in SNP. Therefore, PP/DS must alsogenerate complete planned orders (planned orders with all componentsand all required activities and resource reservations). These orders can

then be used to determine the detailed dates/times and the ordersequence taking into account the sequence-dependent setup activity.

The following options exist for transferring the SNP production plan to aPP/DS production plan:

Using a horizon to separate SNP and PP/DS: You can use theconversion to transfer the SNP production plan to a PP/DS

production plan.

SNP planning and PP/DS planning are performed in differentplanning versions. You can use Demand Planning to transfer the

SNP production plan to a PP/DS production plan.

Using a horizon to separate SNP and PP/DS: You can use aprocurement planning heuristic to transfer the SNP production plan

to a PP/DS production plan.

8/12/2019 APO_Note1


The problem of advance production

The requirement of a product is often subject to strong seasonalfluctuations. If there are insufficient capacities within a period, the SNP

optimizer or capacity leveling can shift the production to a previousperiod. In this period, the total number of product requirements is smallerthan the total number of receipt elements planned by SNP. If this periodmoves to the PP/DS horizon and a PP/DS heuristic is executed, the PP/DS

heuristic may adjust the receipt elements in the PP/DS horizon to theproduct requirements, that is, they are reduced. This destroys the stock

build-up planned by SNP. At the height of the season, it is no longerpossible to create sufficient receipt elements.

Therefore, one criterion for evaluating the procedures for the integration

of SNP to PP/DS is the way in which the procedure supports advanceproduction.

SNP->PP/DS conversion

First, the conversion is discussed. If you use this procedure, SNP is usedto create all of the planned orders. The SNP planned orders are converted

to PP/DS planned orders in a conversion process. This results in thefollowing planning process:

SNP planning is used to determine the sources of supply.

You want the sources of supply selected by SNP to be transferred toPP/DS planning.

SNP plans in planning periods (usually in weekly or monthlybuckets). PP/DS plans in accordance with the lot sizes required for

Execution. When SNP receipt elements are converted to PP/DSreceipt elements, you want the system to distribute the receipt

elements to the lot sizes required in the production.

Planning/optimization of the sequences and the resourcereservations then takes place in PP/DS.

Procedure===========

You use transaction /SAPAPO/RRP_SNP2PPDS or the report /SAPAPO/RRP_SNP2PPDS to convert the SNP receipt elements in the

PP/DS horizon to PP/DS receipt elements.The quantities of PP/DS receipt elements are no longer changed after the

conversion. No procurement planning heuristics are executed in thePP/DS. Of course, you can continue to use all procedures of detailed

8/12/2019 APO_Note1


scheduling and all procedures used for the transfer to Execution for thePP/DS receipt elements. You can therefore use the PP/DS optimizer to

schedule and reschedule the PP/DS receipt elements. You can execute DSheuristics. The PP/DS planned order can be rescheduled in the graphicalplanning table. This planned order can be checked using an ATP check

and the conversion to a production order can be triggered in APO.

Settings==============

This procedure requires the following settings:

The PP/DS horizon is greater than or equal to the SNP productionhorizon.

The planning procedure in the product master is set to manual

planning.

The conversion from SNP to PP/DS is carried out on a regular basis.An SNP receipt element may be split into several PP/DS receipt

elements during this conversion (the system therefore creates lotsthat can be produced).

You use an infinite scheduling strategy for the conversion.

You must set an SNP planning area and a package size to convert

the SNP receipt elements to PP/DS receipt elements.

You must execute an MRP planning run at regular intervals (theconversion and the MRP planning run do not have to be performed

in a specific sequence or at the same frequency).

Setting The Horizons=========================

As of APO Release 3.1, you can select a PP/DS horizon that is larger thanthe production horizon. This can be put to good use here. Set a very smallproduction horizon. This also enables SNP planning to create new plannedorders in the short-term area. These new planned orders may soon haveto be converted to PP/DS planned orders so that they are correctly sorted

into the setup sequence. The PP/DS horizon is relevant for this. ThePP/DS horizon can be larger than the SNP production horizon.

Strategy Profile For SNP->PP/DS Order Conversion=============================================

===========================The purpose of the conversion is to transfer SNP planning results to

PP/DS planning as accurately as possible. The system tries to adjust thePP/DS orders as closely as possible to the SNP planning requirements.

8/12/2019 APO_Note1


The PP/DS orders are only scheduled during the conversion, but they arenot planned. Heuristics, MRP ,or optimization can be used to plan the

results after the conversion.During the order conversion from SNP to PP/DS, the scheduling uses the

start time or the end time from the period pattern of SNP planning

(bucket).With the "Backward" strategy setting, the system transfers the end time

of a bucket and tries to schedule from the "Backwards" time towardstoday. During this, the working times of the resource are taken into

account. If you have a finite resource and a finite strategy, the capacityutilization of the resources is also taken into account. If the working timeof the resource is specified, for example, as 08:00 to 17:00, the system

will try to schedule backwards from 17:00 instead of schedulingbackwards from 23:59:59 (bucket finish). The search for a suitable slot

on a resource ends at the beginning of the planning horizon. This is

determined by the current time and the offset in the strategy profile. Thebeginning of the bucket is therefore ignored during backward scheduling.

If the system is unable to find a sufficient gap on a finite resourcebetween the beginning of the planning horizon and the end of the bucket,

it cannot convert the SNP order using backward scheduling.With the "Forward" strategy setting, the system transfers the start time ofthe first activity of an SNP order and it tries to create a PP/DS order fromthat time into the future. In this case, similar to backward scheduling, the

capacity utilization with finite resources and the working times of theresource are taken into account. If the working times of the resource are

defined as 08:00 to 17:00, the system will try to schedule a PP/DS orderonly after 08:00 towards the future (instead of 0:00:00 which is the startof bucket). The search for a suitable slot on a resource takes place up to

any time in the future. The bucket end from SNP planning is ignored here.If you have the planning direction "Backward with Reverse", the systemcreates the PP/DS order with forward scheduling if no suitable slot could

be found using backward scheduling.The planning direction "Forward with Reverse" is not useful for convertingSNP planned orders. There is no point in time where forward scheduling

would switch to backward scheduling.

Using a finite scheduling strategy (find slot, insert mode, squeeze in)during the conversion of SNP planned orders to PP/DS planned orders hasthe following disadvantages:

A finite strategy has a negative impact on system performance.

During the conversion of SNP planned orders to PP/DS plannedorders, sequence optimization is not carried out. The schedulingresult may be very poor if you use sequence-dependent setup

activities and finite planning.

8/12/2019 APO_Note1


The PP/DS planned orders may be scheduled in a bucket that is notthe bucket SNP earmarked. In this case, SNP planning loses itssignificance. In addition, it becomes more difficult to check the

correct modeling of capacities in SNP. For further information aboutthis, read the section "Available Capacity in SNP and PP/DS".

We therefore recommend that you use an infinite planning strategy toconvert SNP planned orders to PP/DS planned orders. The system willthen create all of the orders of a bucket at the same date. After theconversion, you can improve the planning result using, for example:

A resource heuristic

The PP/DS optimizer

If SNP planning was carried out finitely with bucket resources and if notall planned orders can be planned in the bucket planned by SNP, theavailable capacity of the bucket resource may be too large. Checkwhether the available capacity for the bucket resource is too large.

When you make the general settings in the strategy profile, you must

take the following aspects into account:

The validity periods for the orders must be taken into account.

The desired availability date does not influence order scheduling.

We recommend infinite scheduling as the scheduling mode.

The planning direction forward scheduling with reverse is not usedin the conversion from SNP to PP/DS.

When you make the settings for dependent objects in the strategy profile,you must take the following aspects into account:

You must ignore fixed and dynamic pegging.

You must take the maximum intervals into account.

Take into account that you must use compact scheduling.

During compact scheduling, the system tries not to create gaps when itschedules the orders. This impairs system performance.

8/12/2019 APO_Note1


Relationships must always be taken into account.

These settings apply to APO Release 3.0 and 3.1.

Splitting SNP Receipt Elements=============================================

=========The conversion from SNP to PP/DS also entails a change in the planning

semantics from the quantities per planning period that are planned in SNPto orders. The order sizes in PP/DS are determined by technical feasibility,among other things. In many cases, the order quantity required in PP/DS

will not correspond to the production quantity of a planning period.The option of splitting lot sizes during conversion was implemented in

APO Release 3.1. The following options are available:

The quantity of the SNP planned order is transferred 1:1.

The PP/DS planned orders are created using the fixed lot sizes fromthe product master.

The SNP planned order is split up into several PP/DS plannedorders, whose quantity is the maximum quantity of the PP/DS plan.

The PP/DS lot sizes are determined in a BAdI. For more information,

see Note 571118.

The smaller PP/DS orders that are generated in this way are a betterbasis for the requirement-synchronous production in a period.

Setting The SNP Planning Area=============================================

======Order categories are used to select the SNP orders for the PP/DS release.The order categories for the SNP orders are defined in a planning area. Ifa planning area is used during the conversion and this planning area does

not contain any of the specified SNP order categories, the system doesnot select any SNP orders for the conversion.

During the order conversion, you can use the planning area to read theorder categories globally from Customizing. Alternatively, you can use theplanning area to select the order categories for a specific application from

the initial screen of the transaction. The application-specific selectionallows you to define several planning areas, which may contain differentorder categories. As a result, you can use different planning areas in a

flexible way without making global changes in Customizing.

Setting The Package Size (APO Release 3.1)

8/12/2019 APO_Note1


=====================================The packaging of the SNP orders controls system performance during the

creation of PP/DS orders in the liveCache.During this, due to the lot-size calculation, several PP/DS orders can be

created simultaneously. In this case, we recommend that you reduce the

package size because the number of PP/DS orders is greater than thepackage size of the SNP orders when an order is created; this may impair

system performance during the conversion.In large packages, conversion has a disadvantage if at least one ordercannot be created during the PP/DS order creation. As a result, no SNPorders contained in the package are converted. However, the number ofunconverted SNP orders and information about the quantity, availability

date/time, and the location products affected are recorded in the planninglog. It distinguishes between incorrect SNP orders and SNP orders that

can be subsequently converted in the second run.

We recommend that you keep the package size as small as possible toensure that the system converts as many orders as possible. However,

this has a negative impact on system performance.Alternatively, you can start the conversion twice: Once with a bundle ofSNP orders in large packages (200, for example). The second time, you

can start the same selection with smaller packages (package size = 1 SNPorder, for example). In this way, at least those SNP orders for which no

errors occurred during the PP/DS order creation are converted.In addition, you have the option of restricting the selection to only thoseproducts that can be converted subsequently. In this way, packages can

retain their original package size.

Why Do We Have To Perform An MRP Planning Run?=============================================

=======You cannot use a procurement planning heuristic to plan a product that isprocured using the converted SNP receipt elements. Typically, old receiptelements that no longer correspond to the current planning situation are

deleted and replaced with new receipt elements for this type ofprocurement planning heuristic. In this case, the selection of sources of

supply (source selection) for the old receipt element is lost. From a costpoint of view, however, the selection of sources of supply is one of themost important advantages of using the SNP optimizer. If you want to

retain this selection of sources of supply, you cannot executeprocurement planning heuristics in PP/DS.

The planning procedure also determines whether the existing plannedorders are exploded again when you change the plan (PPM or PDS). It isvery useful to explode PP/DS planned orders again when the plans arechanged. This is set in standard Customizing of the "Manual planning"

planning procedure). Only one planning file entry is created for the newexplosion when changes are made to plans. The actual new explosionoccurs in the MRP planning run. An MRP planning run is therefore also

8/12/2019 APO_Note1


required in this scenario.

Disadvantages Of Conversion=======================

The disadvantages of converting from SNP to PP/DS are as follows:

The PP/DS receipt elements are not adjusted to the changedrequirements.

There is no make-to-order production.

There is no PP/DS lot-size calculation.

The PP/DS Receipt Elements Are Not Adjusted To Changes In

Requirement=============================================

=================In this integration scenario, all new receipt elements are exclusivelycreated by SNP. In this way, you can ensure that the SNP source ofsupply determination is always used. On the other hand, only SNP

planning performs the downwards adjustment of receipt quantities whenrequirements are reduced. However, since PP/DS receipt elements are

fixed for SNP planning, this is not always possible in the suitable bucket.If a requirement is reduced within the PP/DS horizon (and if all of the SNP

receipt elements within the PP/DS horizon have already been converted toPP/DS receipt elements), SNP planning is unable to adjust the receiptelements that cover the requirement. Instead, the system has to reduceSNP receipt elements in a later period so that the total number of receiptelements and requirements is correct again. The PP/DS receipt elements

then cover requirements outside the PP/DS horizon.

There Is No Make-To-Order Production===========================

Make-to-order production is not possible. SNP generates all receipt

elements and only converts them to PP/DS receipt elements at a laterstage. SNP planning does not support the make-to-order production.

Lot-Size Calculation In PP/DS==========================

If the PP/DS receipt elements are created using conversion, the systemcannot perform the PP/DS lot-size calculation. The lot sizes of PP/DSreceipt elements are not related to the requirements in the PP/DShorizon. Lot-for-lot order quantity and periodic lot sizes are not

supported.

Advantages===========

8/12/2019 APO_Note1


Lot-size intervals from the PPM are used.

Advance production is possible.

Lot-Size Intervals From The PPM Are Used=============================================

==A common problem, particularly in process industries, is that alternativeresources require different lot sizes in production. For example, a specific

product can be produced in a reactor that can hold 1,000 liters or in areactor that can hold 500 liters. Both alternative resources have

alternative plans (PPMs) with different lot-size intervals. These alternativeresources cannot be planned in the PP/DS procurement planning heuristic

delivered by SAP or in the SNP heuristic. The reason for this is:

The heuristics execute the planning subfunctions in a specific sequence.During this, the system always determines the lot sizes first. Afterwards,the system carries out a selection of sources of supply. During this, the

previously determined lot sizes have a restrictive effect on the selection ofsources of supply. If, in the above example, the lot-size calculation

determines a lot size of 1,000 liters, the production can only take place onthe first reactor. If, on the other hand, the lot-size calculation determines

a lot size of 500 liters, production can only take place on the secondreactor.

The SNP optimizer can correctly plan alternative sources of supply with

different lot-size intervals. In the above example, if the requirement is1,000 liters, the SNP optimizer either creates an order for 1,000 liters

with the first plan or two orders with the second plan, depending on thecosts and the utilization of the resources. The result of the SNP optimizer

can be transferred by converting SNP orders to PP/DS orders.

Advance Production And Deliberate Delays=============================================

===One result of SNP planning may be a requirement, which you want to

cover several planning periods earlier using an advance production. Inparticular, this is often the case if the requirements undergo seasonalfluctuations. By considering storage costs and the costs for alternativesources of supply, the SNP optimizer can determine an optimal stock

policy for the most important products.SNP planning may decide to use a scarce resource to manufacture a

product with a high added value first, and to manufacture another productcompeting for the same resource later.

If a separate procurement planning heuristic is executed in PP/DSplanning, these SNP planning decisions may be destroyed.

The PP/DS procurement planning heuristics work on the assumption thatrequirements are covered as soon as possible. These heuristics do not

8/12/2019 APO_Note1


recognize that a receipt element is intended to cover a requirementoutside a time interval determined by the lot-sizing procedure. If the

receipt element is within the PP/DS horizon but the requirement is outsidethe PP/DS horizon and outside the time interval determined by the lot-sizing procedure, the PP/DS procurement planning heuristic deletes the

old receipt element and does not replace it with a new receipt element. Ifthe peak of the season is reached, even PP/DS planning must recognize

that the requirements cannot be covered immediately.If the conversion from SNP to PP/DS is used, the dates/times determinedby SNP planning are retained. The problems regarding the procurement

planning heuristic do not occur.SNP and PP/DS in different planning versions

Planning Process==============

Central SNP planning is used to determine production plants andtarget stock levels and to carry out a rough feasibility check. SNPplanning is performed in a planning version not equal to "000".

Central SNP planning is copied to planning version "000". Here, itacts as the production program for PP/DS planning in the form ofplanned independent requirements. The production, that is, PP/DS

planning must cover these planned independent requirements.

Due to these planned independent requirements, PP/DS planning iscarried out decentralized.

For incoming sales orders, the ATP check can be used to take thesales order from the production plant that contains unconsumed

forecast or free receipt elements.

The sales orders are offset against the planned independentrequirements. The chronological distribution of the production

program changes. A new PP/DS planning run can adjust the receiptelements to these changes.

Planning/optimization of the sequences and the resourcereservations then takes place in PP/DS.

Procedure==========

You copy stocks, fixed PP/DS planned orders and fixed purchaserequisitions, production orders, and purchase orders (that is, all objects

that can no longer be changed in PP/DS planning) from the active

planning version to the SNP planning version. You use transaction /SAPAPO/VERCOP to copy the version.

8/12/2019 APO_Note1


You execute SNP planning in the usual way in a planning version notequal to "000".

Once you are happy with the SNP planning result, you transfer theproduction plan to Demand Planning using transaction /SAPAPO/LCOUT.Using transaction /SAPAPO/MC90, the planned independent requirement

that is required is generated from the Demand Planning key figure that isdetermined in this way.

You can use either transaction /SAPAPO/LCOUT or transaction /SAPAPO/MC90 to change the planning version. You must copy "000" to

the target planning version for one of the two copy operations.In planning version "000", you execute PP/DS planning with the usual

tools, such as background scheduling using transaction /SAPAPO/CDPSB0.

Planning Version Settings=============================

In the planning version (transaction /SAPAPO/MVM), you can makesettings that prevent safety stocks from being taken into account inPP/DS planning. The safety stocks were already considered during

planning in SNP. Otherwise, the safety stocks are taken into accounttwice, once in SNP and once in PP/DS. The result of this planning is

transferred to PP/DS. In planning version "000", you must therefore setthe PP/DS indicator for taking the safety stock into account to its default

value.In the SNP planning version, you can deactivate the creation of planning

file entries for PP/DS. This indicator has no effect unless a PP/DS planning

run is started in this planning version or an MRP heuristic is carried out inthe planning version. However, system performance is improved if no

unnecessary planning file entries are created. We therefore recommendthat you do not set the indicator for "PP/DS: Change planning active" in

the SNP planning version.Conversely, you can deactivate the creation of planning file entries for

SNP in the active planning version "000". In the planning version "000",do not set the indicator for "SNP: Change planning active".In planning version "000", PP/DS change planning is active.In the SNP planning version, SNP change planning is active.

Requirement Strategy Settings In The Product Master=============================================

=====A PP/DS procurement planning heuristic initially covers the planned

independent requirements that were generated from SNP planning. Theseplanned independent requirements can be consumed against sales orders

at a later stage. Requirement strategy 20 and the consumption periodmust be set in the product master for this purpose.

Very often, the production plants will have to not only cover the salesorders, but also stock transfers to other plants or dependent requirements

arising from further processing of the product. In this case, we require

8/12/2019 APO_Note1


what is called "subassembly planning".Set the subassembly planning as follows:

You require a category group containing the categories of all requirementsagainst which planned independent requirements are to be offset. You

create the category group using transaction /SAPAPO/SNPCG. Depending

on what you require, the category group contains categories for salesorders, dependent requirements, and stock transfer requirements.

Afterwards, create a new requirement strategy in Customizing(transaction SPRO, menu path: SAP APO -> Master Data -> ProductMaster -> Specify Requirements Strategies). If planned independent

requirements have the category "FA" and the assignment mode "1", theyare offset against all categories from the new category group.

Set the indicator for subassembly planning in the product master and setthe new requirement strategy.

Version Copy Settings===============================

The version copy is executed using transaction /SAPAPO/VERCOP. Copythe master data and the transaction data and select the checkbox for theorder data. You must at least specify the categories for stocks, production

orders, purchase orders, firmed planned orders, and fixed purchaserequisitions.

All receipt elements that are fixed for PP/DS planning must be copied tothe planning version of SNP planning for the following reason:

If the receipt elements are not copied, SNP planning does not know about

these receipt elements. In this case, SNP planning creates new SNPreceipt elements to cover the requirements for the product. Very often,these new SNP receipt elements have another source of supply and will

utilize other resources. SNP planning and PP/DS planning start to deviatefrom each other.

The SNP optimizer can plan stock transfers and the production in a waythat ensures optimum use of existing fixed receipt elements. Of course,this is particularly useful when the requirements and the fixed receipt

elements are in different locations. The fixed receipt elements must alsobe known to SNP planning in this case.

Stock Transfers============

In the scenarios described above, the sales orders are returned directlyfrom the production plants. This is the simple scenario. The ATP check

selects the production plant.If the sales orders are delivered from distribution centers and if there arepossibly several alternative production plants for supplying a distributioncenter, stock transfer purchase requisitions must be created for supplying

the distribution center. You have the following options for this:

8/12/2019 APO_Note1


As of APO Release 3.1, the rules-based ATP check allows you tocarry out multilevel checks and to create stock transfers, if

required. In this case, the ATP check first checks the availability inthe distribution center. If there is no availability in the distribution

center, the ATP check identifies other possible location

substitutions. In the master data of the rules-based ATP, locationsubstitutions are maintained between the distribution center and

the production plant. After this, the ATP check checks theavailability in the production plant. If there is availability in the

production plant, the ATP check creates a stock transfer betweenthe production plant and the distribution center. For this purpose,

set the "Stock Transfer" activity for the location productsubstitutions in integrated rule maintenance (transaction

/SAPAPO/RBA04).

You can use deployment to distribute the surpluses from the receiptelements in the production plants to the distribution centers.

As of APO Release 4.0, you can copy SNP receipt elements from aninactive planning version to the active planning version. Transaction

/SAPAPO/VERMER or report /SAPAPO/VERSION_MERGE areprovided for this. Using this transaction, you can copy SNP stock

transfers from the planning version for SNP planning to theoperative planning version "000". In planning version "000", youcan either transfer these SNP stock transfers directly to the OLTP

system (for example, an R/3 system) or convert them to PP/DSstock transport requisitions. The advantage of converting them toPP/DS stock transport requisitions is that you can then restrict the

purchase requisitions being transferred to R/3 to purchaserequisitions within a certain timeframe.

Advantages Of Planning In Separate Planning Versions=============================================

===

Executing SNP planning and PP/DS planning in different planning versionshas the following advantages:

There is a high degree of stability in SNP planning.

Checked SNP plans are released to PP/DS

SNP planning and PP/DS planning are performed at their ownfrequency.

Distribution to several APO systems is possible (in theory).

Stock build-up is enabled in SNP.

8/12/2019 APO_Note1


Adjusting the production to the requirements is possible.

Make-to-order production is possible.

There are no restrictions for periodic lots in PP/DS.

Stability Of Planning======================

SNP planning is frequently used for medium-term to long-term timeframes. With these time frames, it does not always make sense to include

all current changes to the actual data immediately in SNP planning:

The SNP planner often wants to create and compare several

alternative plans. However, these plans can only be compared if nochanges were made to the basic requirement data between the

creation dates of the plans.

A group of SNP planners works simultaneously on creating subplansfor individual product groups, geographical regions, and so on.These subplans are later merged into an overall plan. The samedetermining factors that were taken into account in creating the

partial plans must also apply in evaluating the quality of the overallplan.

If you execute SNP planning in your own planning version, you can selectthe time of the version copy and thus specify exactly which data is

included in SNP planning and how often the data is updated.

Checked SNP Plans Are Released To PP/DS=====================================

If you execute SNP planning and PP/DS planning in the same planningversion, all changes in SNP planning are immediately taken into accountin PP/DS planning. If, for example, an SNP planned order generates adependent requirement for a component within the PP/DS horizon, a

PP/DS planning run will try to cover this dependent requirement.However, in many cases this measure may be premature because the

SNP planned order will be changed several times.If SNP planning and PP/DS planning are executed in different planningversions, you have the option to release only checked, reconciled, or

approved SNP plans to PP/DS planning.

SNP Planning And PP/DS Planning Are Performed At Their Own Frequency=============================================

=============As mentioned above, SNP planning is a period-based planning function

8/12/2019 APO_Note1


and the intervals used to execute SNP planning are often based on theseplanning periods. PP/DS planning, in contrast, operates so that it isaccurate to the second and should therefore be executed far more

frequently.As long as SNP planning and PP/DS planning are carried out in different

planning versions, each planning can operate at its own frequency.

Distribution Across System Boundaries=============================

The BAPI "PlanningBookAPS" is one of the building blocks which allowsSNP planning and PP/DS planning to be carried out on different APO

systems. For this, the time series from Demand Planning are exchangedbetween the systems.

All other alternatives discussed here execute SNP planning and PP/DSplanning in the same planning version. Distributing the functions across

different computers is not possible in this case as a matter of principle.

Stock Build-Up Is Enabled In SNP=============================

If SNP planning wants to execute a stock build-up to cover a seasonalrequirement that occurs at a later stage, this stock build-up is transferred

to PP/DS planning. This occurs on the condition that the SNP receiptelements are transferred to Demand Planning using transaction

/SAPAPO/LCOUT. Only SNP receipt elements show the stock build-up.Another condition is the creation of planned independent requirements

with final assembly using transaction /SAPAPO/MC90. These are the onlyrequirements that allow advance production.

Adjusting The Production To The Requirements Is Possible===========================================

Planned independent requirements are generated from the result of SNPplanning. These planned independent requirements are consumed with

sales orders, and dependent requirements and stock transferrequirements for the same product, if applicable. The planned

independent requirement is reduced and the sales order, the stock

transfer requirement, or the dependent requirement is taken into accountfor the requested delivery date or the requirement date/time. Thischanges how the requirements are chronologically distributed. A new

PP/DS planning run takes account of this change in distribution.All sales orders are taken into account in PP/DS planning even if the totalof sales orders exceeds the quantity planned using planned independentrequirements. In this case, an adjustment in relation to the confirmed

requirements also takes place in PP/DS planning.However, automatic adjustment (reduction) of the planned productiondoes not occur where the quantity planned using planned independentrequirements exceeds the total of sales orders and any stock transfer

requirements and dependent requirements. Stock build-up would not be

8/12/2019 APO_Note1


possible either if the planned production was adapted to the confirmedrequirements in this case.

If you do not want to use the stock build-up, you have two other optionsfor handling a situation in which the quantity of planned independent

requirements exceeds the total of sales orders:

As of APO Release 3.1, you can use the conversion rule to checkwhether a planned order or purchase requisition is actually requiredfor a sales order. If the planned order or purchase requisition only

covers a planned independent requirement, conversion to aproduction order or purchase order is not possible. The check takes

place on several levels.

Requirement strategy 30 is set in the product master. The systemthen generates planned independent requirements for planning

without final assembly. To cover these planned independentrequirements, a PP/DS procurement planning heuristic creates

planned orders or purchase requisitions which cannot be convertedinto production orders or purchase orders. The "Planning withoutFinal Assembly" function cannot be inherited to lower assemblies.You can therefore prevent final assembly only at finished product

level. Therefore, we recommend the conversion rule.

Make-To-Order Production Is Possible

=============================The planned independent requirements created using SNP planning can

also be consumed with sales orders for make-to-order production. For thispurpose, you must use a requirement strategy with assignment mode "2"in the product master. Usually, requirement strategy 30 (planning withoutfinal assembly) is used. If you want to combine make-to-order production

with the option of stock build-up, you need a planned independentrequirement for the planning with final assembly. For this purpose, create

a separate requirement strategy with planning segment initial andassignment mode #2'.

Disadvantages:==========

Planning SNP and PP/DS in separate planning versions has the followingdrawbacks:

The SNP source selection can not always be transferred.

Why Is It Not Always Possible To Transfer The Source Selection?

==================================================================

8/12/2019 APO_Note1


By defining alternative plans, you can model and plan alternativeresources within a production plant in SNP. SNP planning generates

planned orders with different sources of supply or plans. All these plannedorders are aggregated to a single key figure in the Demand Planning. Inthis case, PP/DS planning no longer possesses any information about the

resource selection in SNP. As a result, only the source selection at ahigher level, that is, at production plant level, can be transferred to PP/DS

planning.

PP/DS MRP with standard lot size heuristic

Converting SNP receipt elements to PP/DS receipt elements has somedisadvantages:

The PP/DS receipt elements are not adjusted in relation to changed

requirements within the PP/DS horizon.

Make-to-order production is not possible.

Restrictions apply to the lot-sizing procedures.

Often, users try to avoid the disadvantages of converting SNP receiptelements to PP/DS receipt elements by carrying out both a SNP planning

run and a PP/DS planning run (with a standard lot size heuristic, for

example) in the same planning version. The standard lot size heuristic inPP/DS can handle make-to-order production it can adjust PP/DS receiptelements to changed requirements. In this case, why not simply combine

the two planning procedures? The new objectives are:

SNP plans in buckets (generally in weekly or monthly buckets).PP/DS plans in accordance with the lot sizes required for Execution.Planning with the PP/DS MRP distributes the quantities planned by

SNP into lots that can be produced.

The PP/DS receipt elements are adjusted in accordance with thechanged requirements.

SNP always plans for make-to-stock production. However, you wantsome of the sales orders to be covered by make-to-orderproduction. SNP planning works on the basis of planned

independent requirements. The forecast consumption is set so thatthese planned independent requirements are reduced by make-to-order sales orders. Instead, MRP planning in PP/DS is supposed to

create planned orders for make-to-order production.

Algorithm

8/12/2019 APO_Note1


============The procurement planning heuristics in PP/DS, such as the standard lot

size heuristic, carries out the following steps consecutively for eachproduct:

The receipts and the requirements are read.

Net requirements calculation is executed for all fixed receipts andrequirements. SNP receipts outside the PP/DS horizon are fixed to

prevent them from being changed by PP/DS.

Lot-size calculation is carried out for all outstanding requirements.

The reusability is checked for old unfixed receipts.

Old receipts that have not been reused are deleted (SNP receiptsoutside the PP/DS horizon were fixed and are therefore not

changed).

New PP/DS receipts are created if the date/time falls within thePP/DS horizon.

Settings==============

The procedure requires the following settings:

Standard lot size heuristic in the product master (or default valuefrom the planning procedure)

"Planning in Planning Run" planning procedure in the productmaster on the PP/DS screen

Infinite scheduling strategy for the MRP planning run (setting in theprocurement planning heuristic as of APO Release 4.0 or using

transaction /SAPAPO/RRPCUST1).

Net requirements calculation using the first in first out (FIFO)strategy (you can set this in the procurement planning heuristic)

Net requirements calculation on requested quantities (you can setthis in the procurement planning heuristic)

For periodic lots in PP/DS, the planning periods in SNP must begreater than or equal to the periods for the creation of lots in

PP/DS. The period limits for the SNP planning periods are also the

period limits for PP/DS lot-size creation.

8/12/2019 APO_Note1


Safety stocks are taken into account in the PP/DS planning (you canset this in the planning version using transaction /SAPAPO/MVM).

PP/DS horizon is initial.

Delays are permitted in SNP planning (you can set this in theproduct master on the screen SNP1).

An SNP planning run must be executed immediately before eachMRP planning.

Net Requirements Calculation Using FIFO Strategy=========================================

If the default settings are used for the net requirements calculation in

PP/DS, the net requirements calculation first uses fixed receipt elementsto cover later requirements. This also occurs if the requirement is outside

the PP/DS horizon and we would expect it to be covered by the SNPplanning function. If the fixed receipt is used for later requirements, an

earlier requirement may remain uncovered. The PP/DS heuristic creates anew receipt element for this requirement. If the requirement was alreadycovered by an SNP receipt element outside the PP/DS horizon, this SNP

receipt element becomes a surplus (until the next SNP planning).To solve this problem, you must ensure that the delayed fixed receipt

covers the preceding requirement. You have the following options:

The net requirements calculation is carried out using the FIFOstrategy. The relevant settings are made in the standard lot size

heuristic. In APO Release 3.0 and 3.1, you must set the "ConsiderFixed Receipts First" indicator for the FIFO strategy. In APO Release

4.0, set the procedure for the net requirements calculation to"FIFO". Refer also to Note 448960.

If you use the net requirements calculation, a delayed fixed receiptis also assigned to a requirement if the difference is smaller than

the alert threshold for delays. The alert threshold for delays is set inthe product master on the requirements screen.

Why Must Delays Be Allowed In SNP Planning?=============================================

===============If a FIFO strategy is set for the net requirements calculation and if delays

in SNP are not permitted, the effect is as follows:PP/DS planning creates receipt elements for the requirements within the

PP/DS horizon. However, some of these elements are delayed. The

delayed receipt elements are not used by the SNP net requirementscalculation to cover the earlier requirements. The delayed receipt

8/12/2019 APO_Note1


elements are therefore available for requirements outside the PP/DShorizon. These requirements are neither covered by PP/DS planning nor

by SNP planning.You set the maximum delay for the SNP optimizer in the product master

on screen SNP1.

The net requirements calculation in PP/DS and SNP should return thesame result if PP/DS and SNP are to cover the same requirements.

Why Perform The Net Requirements Calculation On Requested Quantities?============================================

In SNP planning, planning is usually executed for requested quantities. Inthe PP/DS standard lot size heuristic, you can choose between planning

with requested or planning with confirmed quantities in the sales order inAPO 3.0 and 3.1. The following problems may occur if you configure thatPP/DS planning is carried out on the basis of the confirmed quantities:

A sales order is entered but it is not confirmed. SNP planningcreates receipt elements based on the requested quantity in the

sales order. If the sales order moves to the PP/DS horizon, PP/DSplanning no longer recognizes the requirement from the sales order.In this case, PP/DS planning deletes the SNP receipt element, but it

does not create its own PP/DS receipt. As a result, the next SNPplanning must create a receipt again to restore the quantity balance

from the SNP planning point of view. The planning functionconstantly switches between two statuses.

In this scenario, SNP planning and PP/DS planning are performedon the same requirements. The total requirements comprise salesorders, dependent requirements, stock transfer requirements, and

planned independent requirements. The planned independentrequirements are usually consumed against the sales orders. Thesystem can carry out this consumption either with the requested

quantity or with the confirmed quantity. The setting for the forecastconsumption must correspond to the planning setting. The forecast

consumption allows only one setting.

Why Does The PP/DS Horizon Have To Be Initial?============================================The net requirements calculation carried out in SNP is different to the

calculation performed in PP/DS. In SNP, all requirements for a planningperiod (bucket) are covered by the receipt elements in the same planningperiod. To cover new requirements within a planning period, SNP planning

often creates a receipt element in the middle of or at the end of theplanning period. This always occurs in SNP for daily periods and

depending on the period factor for other planning periods. In contrast,receipt elements in PP/DS must be available before the requirement for it

8/12/2019 APO_Note1


to be covered.This causes the following problem: SNP planning created an SNP receiptwithin or at the end of the planning period to cover a requirement at the

start of the planning period. From the PP/DS point of view, therequirement appears to occur before the receipt element. Therefore, the

requirement cannot be covered by the existing SNP receipt element.If both the SNP receipt element and the requirement are within the PP/DS

horizon, PP/DS planning simply deletes the SNP receipt element andcreates a new PP/DS receipt element. The receipt elements total thencorresponds again to the requirements total. There is no sign of the

problem.However, if the requirement is within the PP/DS horizon and the SNP

receipt element is outside the PP/DS horizon, PP/DS planning must notdelete the SNP receipt element. Unnecessary SNP receipt elements are

present until the next SNP planning.

This is particularly irritating if these SNP receipt elements generatedependent requirements. The system can no longer tell whether

dependent requirements have originated from SNP or PP/DS. In this case,it is likely that too many component requirements will be procured.To avoid this problem, let the PP/DS horizon always move on by oneplanning period. The PP/DS horizon moves on by one planning period

each time if the following conditions are met:

You use APO Release 4.0.

In addition, the PP/DS horizon is initial. If you have an initial PP/DShorizon, the SNP production horizon applies as the default value for

the PP/DS horizon.

What Is To Be Considered When Using Periodic Lots In The PP/DS?=============================================

========For periodic lots, you expect the system to cover all requirements within a

period using a single receipt element. If part of the period falls outside

the PP/DS horizon, the system also expects all requirements (inside oroutside the PP/DS horizon) to be covered by a single PP/DS receiptelement. If the system had to increase the PP/DS planned order duringthe period by the quantities of the additional requirements trickling into

the PP/DS horizon, all planning actions already carried out with this PP/DSreceipt element would be invalidated. In this case, the user would have torepeat a scheduling run, rescheduling, campaign assignment, ATP check,

and so on.If the requirements were in different SNP planning periods, the part of thePP/DS lot size period outside the PP/DS horizon would still be covered by

user-defined SNP receipt elements. Accordingly, the shortage for thePP/DS would be smaller. PP/DS planning could cover only part of the

8/12/2019 APO_Note1


requirements in the period.Therefore, the following conditions are required: Firstly, the PP/DS

horizon must move on by SNP planning periods, and secondly, the periodsfor PP/DS lot-size calculation must not be greater than the planning

periods.

The period boundaries of the SNP planning periods must be the same asthe limits of the periods used in the PP/DS lot-size calculation. If monthlyperiods are used in SNP, the lot-size calculation can create daily lots, 10-

day lots, or monthly lots in PP/DS, but it cannot create weekly lotsbecause Mondays usually do not fall on the first day of a month. If weekly

periods are used in SNP,daily or weekly lots can be used in PP/DS.

Why Must SNP Planning Be Executed Before The MRP Planning Run?=============================================

=======================The PP/DS horizon is relevant only for make-to-stock production. Formake-to-order production, the entire time axis is within the PP/DS

horizon. A make-to-order sales order outside the PP/DS horizon reducesthe planning quantity and acts as a separate requirement element for the

MRP planning run. MRP planning covers this requirement using a newplanned order. If no SNP planning run is executed previously, the SNPplanned order still contains its original quantity for the make-to-stockproduction. The quantity of the SNP planned order is too large. Thecombined totals of SNP planning and PP/DS planning constitute an

overproduction. Too many components are procured and too manyresources are reserved.

Disadvantages==========

The SNP selection of sources of supply is lost.

There are restrictions for periodic lots.

Advance production (early build) is not possible, or it is onlypossible with restrictions.

The planning process is complicated.

There is a lack of transparency.

The SNP Selection Of Sources Of Supply Is Lost======================================

During this procedure, the SNP orders are deleted by the MRP heuristic inthe PP/DS horizon. Instead, the MRP heuristic creates PP/DS receipt

8/12/2019 APO_Note1


elements to cover the requirements within the PP/DS horizon. The PP/DSreceipt elements are in no way related to the original SNP orders. Thesource selection of the SNP order cannot be transferred to the PP/DS

order. The PP/DS heuristic carries out its own source selection which, ofcourse, returns a result that differs from the SNP planning result.

This is only a problem if alternative sources of supply actually exist for theproduct. It is not a limitation if single sourcing is used. However, it is aserious limitation if alternative sources of supply are available. After all,

SNP planning is carried out specifically to optimize the selection of sourcesof supply. If the results from this planning cannot be copied to PP/DS

planning, the entire SNP planning run serves no purpose.You could try to avoid this drawback by converting SNP planned orders to

PP/DS planned orders between the SNP planning run and the PP/DSplanning. However, this will not stop PP/DS planning from performing anew source selection. PP/DS planning always carries out a new source

selection if a quantity or date/time for the converted planned order doesnot match the requirement. The planning process is complicated further

by the additional conversion.

Advance Production (Early Build)====================================

Of course, SNP planning can meet a future requirement with an earlierprocurement. This option is particularly useful for seasonal fluctuations in

requirements and limited capacities. Depending on the storage andprocurement costs, the SNP optimizer can find a solution which allows the

requirements from a future period to be covered using a production in anearlier period. The procurement planning heuristics provided by SAP inPP/DS, on the other hand, can support only requirement-synchronous

procurement. If the requirement is outside the PP/DS horizon but SNP hasscheduled a receipt within the PP/DS horizon, the standard lot size

heuristic would delete the SNP receipt from the PP/DS horizon withoutreplacing it.

To solve the problem, some PP/DS heuristics have an indicator for takinginto account shortages outside the production horizon. If this indicator is

selected, the PP/DS heuristic adds up all shortages outside the PP/DShorizon and within the period specified in the heuristic. Due to the limitedresources available, SNP cannot cover these shortages itself and expects

these product requirements to be covered by receipt elements in thePP/DS horizon.

If you want to retain a stock build-up planned by SNP, you must ensurethe following aspects:

Select the indicator for taking account of shortages outside theproduction horizon in the PP/DS heuristic. The horizon should

include a seasonal cycle.

8/12/2019 APO_Note1


The SNP and PP/DS planning runs must be carried out in the correctsequence. SNP planning must always be executed first.

If the indicator for taking account of shortages outside the production

horizon is set, all shortages in the specified period are added up andmoved to the end of the PP/DS horizon. There, they are treated as ONE

requirement. If there is an exact lot size, the entire stock build-up iscarried out by a single receipt element. This receipt element may be verylarge and therefore difficult to deal with or difficult to plan. Check whethera maximum lot size can be used to cover the requirement using several

receipt elements.

The Planning Process Is Complicated============================

As described above, an SNP planning run must be executed before everyPP/DS planning run. This is not how an ideal planning run is expected to

work.SNP planning is a long-term and period-based planning system. The

planning periods in SNP are often weeks or months. From an SNP point ofview, there is no reason to execute SNP planning more often than onceper planning period. This is unless the previous period was so poorly

planned that the actual data differs significantly from the planned dataand this actual data is to be taken into account in SNP planning.

System administration is also complicated by the interdependencies

between the planning runs. Ideally, the sequence of planning runs shouldbe variable.

In a system with 7*24 hour availability, it is even necessary for eachplanning run to store a consistent overall plan when it is completed

because the planning results may be read at any time. This requirementcannot be met by integrating SNP and PP/DS with the approach

described.

Lack Of Transparency=====================

During the conversion from SNP to PP/DS, conflicting objectives mayarise. The objectives of SNP and PP/DS will contradict each other if SNPtries to avoid seasonal capacity overloads using an advance production

and at the same time, PP/DS only releases production if the sales order isalready available or PP/DS executes a make-to-order production or PP/DS

always adapts the planning to sales orders.If SNP planning and PP/DS planning are executed in separate planningversions, the planning results of both plans are always available and

comprehensible (as far as the optimizer allows). If there are conflictingobjectives, the SNP planner and the PP/DS planner can use their

respective planning results for the required adjustments.If SNP planning and PP/DS planning are carried out in a single planning

8/12/2019 APO_Note1


version, there is a risk that the SNP planning result is destroyed by PP/DSplanning (at least within the PP/DS horizon). As a result, the results ofSNP planning are no longer comprehensible and they can no longer be

used for a reconciliation between the planning levels that may berequired.

Functions that behave differently in SNP and PP/DS

Safety Days' Supplies======================

SNP and PP/DS treat safety days' supplies differently. In SNP, thefollowing logic applies: In period n, cover the requirements of periods n ton+safety days' supplies. In PP/DS, the following logic applies: Cover therequirements from period n in period n-safety days' supply. If the safetydays' supply is static, these two logics differ only for the period from the

current point of time until the end of the safety days' supply. SNP createsonly one receipt element for this period, while PP/DS may create severalreceipt elements (provided that there are several requirements in thisperiod and lot size grouping does not take place). The differences are

greater for time-dependent safety days' supplies. SNP uses the followinglogic: In period n, cover the requirements of periods n to n+safety

stock(s)". SNP uses the safety days' supply at the time of the receiptelement. PP/DS uses the following logic: Cover the requirements fromperiod n in the period n-safety days' supply (or safety days' supplies).

PP/DS uses the safety days' supply at the time of the requirement

element.Solution

*Header Data

Affected Releases

Date post:	03-Jun-2018
Category:	Documents
Upload:	suryanarayana-tata
View:	221 times
Download:	0 times

APO_Note1

Documents