Converting ATP Tree Structures
Use
An ATP check in a
sales order can, with the corresponding check configuration, determine which
and how many of the finished products that are required by the customer, are
not available in the check location, but could be procured from Production Planning
and Detailed Scheduling
(PP/DS) through stock transfers from other locations (location determination
with
rules-based ATP),
or final assembly of available components (
multilevel ATP).
Here, components can also be replaced by alternative components (product
substitution with rules-based ATP).
During the
multilevel ATP check, the system explodes the BOM structure of the finished
product. The result of this ATP check are
ATP tree
structures that are created by the system when the sales order is saved in
SAP APO. There is an ATP tree structure for each request schedule line in the
sales order. An ATP tree structure contains, among other things, the
requirements data (dates, quantities and sources of supply) for the required
finished products and components. PP/DS only creates the procurement proposals
for these requirements (stock transport requisitions or planned orders) when
converting the ATP tree structures. Depending on the time position of
an ATP tree structure, the conversion is either automatic immediately after
the sales order is saved, or is controlled by the user at a later time.
Integration
You have integrated the following systems:
· An OLTP system for processing sales orders
·
An SAP APO system
for the
global
availability check (Global ATP) and for PP/DS
Prerequisites
· Conversion is only possible in the active planning version 000.
· In SAP APO, you have maintained all master data required for PP/DS (for example, locations, products, resources, plans (PPM or PDS) and transportation lanes)
If you implement the multilevel ATP check, you should only create procurement proposals for the finished products and their components in PP/DS by converting the ATP tree structures. You should not carry out any automatic planning in PP/DS and should only make manual changes to the procurement proposals if required. Define a corresponding planning procedure in the location product master for the relevant products; for example, the standard planning procedure 5 provided by SAP.
For more
information, see
Multilevel ATP
Check.
· If you need to carry out another ATP check after the conversion of the tree structures because of changes to sales orders, you should use the function Recreate Procurement Proposals. In the case of make-to-stock production the use of fixed pegging is a prerequisite for this. So that the system is able to create fixed pegging relationships between the receipt elements and the pegged requirements, during conversion of the ATP tree structures, you must select the option Create Fixed Pegging Relationships in the field Fix. Pegging CTP/ATP in the PP planning procedure, in Customizing for Production Planning and Detailed Scheduling.
Features
Conversion time
The conversion time depends on the following horizons and dates:
· Scheduling horizon for the conversion of ATP tree structures
· Requirements dates in the ATP tree structure
PP/DS immediately converts the ATP tree structure when the sales order is saved
· If the earliest requirements date for components is within the scheduling horizon or
· If the latest requirements date for finished products is within the PP/DS horizon
If none of these conditions are fulfilled when saving the sales order, the system saves the ATP tree structure in SAP APO. In this case you can only convert the ATP tree structure online or in the background when one of the conditions given above is fulfilled. Here, there is an offset for the horizons with which you can achieve an earlier conversion.
You maintain the scheduling horizon for the conversion of ATP tree structures in Customizing for Production Planning and Detailed Scheduling under Maintain Global Parameters and Defaults. You maintain a location product specific PP/DS horizon in the location product master. If no location product specific PP/DS horizon exists, the system uses the PP/DS horizon from the planning version. You maintain these in Model and Planning Version Management.
Conversion scope
During conversion, PP/DS tries to create procurement proposals for all the requirements of an ATP tree structure. Specific creation of procurement proposals for individual requirements is not possible.
Process flow for conversion, error handling and logging
If all the requirements in the ATP tree structure are converted successfully, and all the procurement proposals are scheduled successfully, PP/DS deletes the ATP tree structure. If the conversion fails, for example, due to unsuitable detailed scheduling strategies (see below), the ATP tree structure is retained; that is, PP/DS does not create any procurement proposals and does not delete the ATP tree structure. PP/DS lists the errors in the planning log. You can restart the conversion after you have removed the causes of the errors; for example, set different detailed scheduling strategies.
Order data
PP/DS creates a procurement proposal with a receipt quantity equal to the desired requirements quantity for each requirement in the ATP tree structure. (This corresponds to the lot-sizing procedure Lot-for-lot order quantities; PP/DS does not take the lot-sizing procedure defined in the location product master into account.) For products produced in-house, the system also considers the assembly scrap in the procurement quantity.
Configuration and priority of a procurement proposal are taken from the sales order. As source of supply, PP/DS uses the source of supply from the ATP tree structure. In rules-based ATP, a location substitution at finished product or component level in PP/DS leads to a stock transport requisition, a product substitution at component level to a planned order, in which the components are substituted accordingly by alternative components. A multilevel ATP check can result in planned orders for finished products or components, which put together the available components or subcomponents.
PP/DS copies the ATP data from the requirements in the ATP tree structure (for example, confirmed quantities, confirmed dates, missing parts indicators and ATP status) to the procurement proposals. The ATP data is in the product view. For later online conversion, the system also displays the order data in the results screen.
The receipt quantities of the procurement proposals are specified by the ATP check. If you want to split procurement proposals in PP/DS or want to combine them to make a large procurement proposal, delete the procurement proposals created from the ATP tree structure manually and manually create procurement proposals with smaller or larger quantities. You may not do this if products are configured or if a product substitution has been carried out during the ATP check. It is not possible to manually create orders for configured products. If you create an order for a product in which the ATP check has substituted components, PP/DS does not consider any ATP rules, rather it uses the designated components in the plan (PPM plan, iPPE process structure or runtime object).
Plan explosion for products produced in-house
With immediate conversion after a multilevel availability check, PP/DS does not re-explode the plan (PPM plan or production data structure) for a product produced in-house, but uses the plan explosion data from the multilevel availability check. With a later conversion, PP/DS reads the requirements data and the source of supply from the ATP tree structure and re-explodes the plan with the requirements data. If a product substitution has been carried out during the ATP check, after the plan explosion, the system substitutes the designated components in the plan with the alternative components determined by the ATP check.
After a planned order is created, PP/DS no longer permits a re-explosion of a plan for this planned order, because a re-explosion could undo existing product substitutions again.
Scheduling the procurement proposals
For scheduling
procurement proposals, the system uses the strategy profile that you have
entered in Customizing for Production Planning and Detailed Scheduling
(PP/DS) under Maintain Global
Parameters and Defaults.
If the order scheduling fails, for example, because a resource is overloaded,
the system does not convert the ATP tree structure and does not create
any orders. You should use
detailed scheduling
strategies with few restrictive settings, for example, with infinite
planning, so that the conversion of the ATP tree structure succeeds. The
scheduling problems, for example, resource overloads resulting from infinite
scheduling, can be solved with the detailed scheduling planning board at a
later date, for example. If you do not execute conversion regularly, the ATP
tree structure may fall into the past. Thus, the strategy profile should
contain at least one detailed scheduling strategy with forward scheduling; the
system can then schedule orders for the requirements in the past, from
today’s date.
Order validity
When scheduling a newly created order, the order validity may be violated; that is, the system schedules the order for a date outside its validity period when a specific component is no longer valid, for example. In this case the system creates an alert. You must solve this planning problem manually by changing the relevant order accordingly. Note that changes that would lead to a re-explosion of a planned order are not possible (see above). For more information see Processing Procurement Proposals Created by a Conversion.
Propagation range
The system does not consider the propagation range during scheduling, that is, there are no product or resource-related restrictions for scheduling.
Create Fixed Pegging Relationships on Conversion of the ATP Tree Structure
During conversion, the system creates the necessary receipt elements on every BOM level. When doing so, it can automatically create fixed pegging relationships between the requirements and the receipt elements. The creation of fixed pegging relationships takes place on all levels of the BOM structure so that the entire order network is linked via fixed pegging relationships. In make-to-stock production, the use of fixed pegging relationships is necessary to ensure that fixed assignments between the requirement and receipt elements are retained. In turn, this is a prerequisite for the function Recreation of Receipt Elements that you carry out during a new ATP check of sales orders for which the ATP tree structure has already been converted. In make-to-order production, fixed pegging assignments are not necessary, because the fixed assignment arises from the account assignment to the sales order.
Repeated ATP check in the sales order
After a change is made to a sales order with a repeated ATP check, the procurement proposals already created from the ATP tree structure could become obsolete. If you implement the function Recreating Procurement Proposals, PP/DS can automatically delete these procurement proposals and replace them with new ones. For more information, see Recreating Procurement Proposals.
Activities
Function |
Menu Path |
Call online conversion Call background conversion |
Area menu for Production Planning under Environment |
Call planning log |
· Area menu for Production Planning under Evaluations → Planning Run Evaluations · Initial screen or results screen of the online conversion under Goto |
Display ATP tree structure |
Area menu for Global ATP under Environment → Technical Monitors |