Function documentation Calculation of Days' Supply 

Use

You use the days' supply to determine for how long stocks and receipts will cover your requirements, to avoid product shortages or stock levels that are too high.

Different days’ supply types give the planner an idea of the priority level he or she should give to any problems that occur.

Background documentation

The system can calculate the days’ supply on the basis of different stock and receipt categories. In addition, you can set in the product master that the system should also take into account early or late receipts when calculating the days’ supply.

For example, if the days' supply is less than a day, then the supply of raw materials to production is endangered.

If the receipt days’ supply is less than the planned delivery time, the planner will also need to take action, however, this situation is less urgent.

The system issues alerts that inform you of critical situations in product availability, or when stock levels are too high.

Prerequisites

Define Days’ Supply Types and Minimum and Maximum Days’ Supply (Customizing)

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  1.  You have maintained days’ supply types and the minimum days’ supply in Customizing for Production Planning and Detailed Scheduling under Order View Maintain Days’ Supply Types.

You can make the following settings:

¡  Receipt and requirement categories

You can define which receipt and requirement categories are taken into account in the days’ supply calculation (for example, the stock category could include locked stock, in addition to available stock).

¡  Days’ supply types

You can define which stock and receipt categories are compared with which forecast and requirement categories.

There are two standard days' supply types that you can copy if you want to create new days' supply types:

§  SAP1 = Days’ supply (contains all stock, requirements and forecasts currently defined in the R/3 system)

§  SAP2 = Receipt days’ supply (contains all stock, receipts, requirements and forecasts currently defined in the R/3 system)

Note

You can copy the standard days' supply types and then delete the categories you do not want to include in the calculation of days' supply.

The system can calculate up to three different days' supply types when you access the Product View or the Alert Monitor. Because there are different types of days’ supply, you can compare the effects of different categories on product availability and check whether you need to take any action.

Example

For example, the following days’ supply types are possible:

-  You take stock and all requirements into account.

-  You take stock, all requirements, and receipts that you are certain to receive, such as production orders or purchase orders, into account.

-  You take stock and all requirements and receipts into account.

¡  Define Minimum Days' Supply and Maximum Days' Supply (for Alerts)

You can define minimum and maximum days’ supplies in days.

For each days' supply type, you can specify the minimum days' supply in days. The system then issues alerts when the days’ supply falls below this level (Below Minimum Days’ Supply).

For each days' supply type, you can also specify the maximum days’ supply in days. The system then issues alerts when the days’ supply exceeds this level (Required days' supply exceeded).

Based on these values, the system issue alerts, warning you of potentially critical situations regarding product availability.

Note

You can use the enhancement APOCV001 to define different minimum days’ supplies for different products, for example.

  2.  You have entered the days' supply types (maximum of three) that are to be calculated by the system in Customizing for the Order View under Set Layout  Maintain General Settings.

There, you can also define that the days' supply is displayed in weeks or months, instead of days, in the planning functions.

Take early and late receipts into account (product master)

In the location-dependent product master, you have defined the Alert Threshold for Earliness and the Alert Threshold for Lateness, which are relevant in the days’ supply calculation for determining the first requirement for which there is not sufficient coverage.

Note

You can use the Business Add-In /SAPAPO/RRP_COVPARAM Time Parameters for Receipts in the Days’ Supply Calculation to influence the way in which the system calculates the days’ supply. There is an example implementation for this BAdI, corresponding to the system behavior up to SAP APO 4.0.  (Until SAP APO 4.0 the days’ supply was calculated taking into account the Maximum Allowed Earliness for a Receipt Element and the Maximum Allowed Lateness for a Receipt Element. As of SCM 4.1, the Alert Threshold for Early Receipts and the Alert Threshold for Late Receipts are used).

Set alert profile (Planning functions or Alert Monitor)

You have either maintained the days’ supply types and values, which you want the system to use for determining alerts, in Customizing, or you have assigned different days’ supply types in the alert profile.

Features

The system calculate the days’ supply on the basis of the days’ supply types that you have maintained in Customizing or assigned in the alert profile.

If you have maintained the Alert Threshold for Early Receipts and the Alert Threshold for Late Receipts in the location-dependent product master, then early or late receipts that are not problematic from the planner's point of view are used to cover requirements. (See Example.)

The days’ supplies determined by the system can be displayed in the product view, the product overview or the Alert Monitor.

Days’ Supply in the Product View

In the product view, the system calculates and displays a maximum of three days' supplies. This means that one value is displayed for each of the days' supply types, of which there are a maximum of three. You see only the days' supply of the selected pegging area (planning segment). Minimum days' supply alerts are also displayed for this pegging area.

Because the days' supply is calculated individually for each pegging area, there may be several different days' supplies for the same product, in the same location and planning version in make-to-order production. The days’ supplies calculated for all pegging areas of a product are displayed in the Alert Monitor, as are the minimum and maximum days’ supply alerts determined by the system.

Example

For example, if you use the days’ supply types SAP 1 (Days’ Supply) and SAP 2 (Receipt Days’ Supply) you see the (stock) days’ supply and receipt days' supply in the product view.

·  Based on the (stock) days’ supply, you can see for how many more days your stock will cover your requirements.

The days' supply gives the number of days (from today) that are left until a requirement cannot be covered by the stock.

·  Based on the receipt days' supply, you can see the number of days within which a receipt must take place in order to cover the existing requirements.

The receipt days’ supply gives the number of days between today's date and the time at which the requirements can no longer be completely covered by the stock or a receipt.

If you have also defined minimum days’ supplies for the days’ supply and the receipt days' supply, then the system also displays any days' supply alerts that it has determined, along with the calculated days' supplies.

For example, you have defined the following minimum days’ supply values:

§  This graphic is explained in the accompanying text Error alert:    5 days

§  This graphic is explained in the accompanying text Warning alert:  10 days

§  This graphic is explained in the accompanying text Info alert:   15 days

If the system determines a days' supply of three days it displays the symbol This graphic is explained in the accompanying text for the error alert next to the days’ supply.

Days' supply in the periodic view

A days’ supply is also displayed in the periodic view of the product planning table and the product view. This days’ supply is calculated differently to the usual days' supply calculation in PP/DS: For the days' supply calculated in the periodic view no alerts are generated.

For more information on the calculation of this days’ supply, see Calculating the Days’ Supply in the Periodic Product View.

Days’ Supply in the Product Overview

In the product overview (and the Product Overview chart in the product planning table) you see the days’ supply and the minimum days’ supply alerts for all selected products.

See Product Overview

Minimum and Maximum Days’ Supply (Alert Monitor)

In the Alert Monitor you see the minimum and maximum days’ supply alerts for all pegging areas for a product.

·  If the days’ supply falls below the minimum days’ supply level the system issues the alert Below minimum days' supply.

·  If the days’ supply exceeds the maximum days’ supply level, the system issues the alert Required days' supply exceeded.

The calculated days' supply for each pegging area is displayed with the values defined for the minimum and maximum days' supply levels.

In the alert profile, you can override the days’ supply types in Customizing, by maintaining up to three different days’ supply types for PP/DS alerts. The days' supply and minimum days' supply alerts are then determined on the basis of these days' supply types.

Example

The following examples illustrate the circumstances under which early and late receipts are taken into account when the system calculates the days' supply.

Early and late receipts that are taken into account

In the location-dependent product master you have entered an alert threshold for earliness and lateness of 72 hours (3 days). Therefore, when calculating the receipt days’ supply, the system also takes into account receipts that occur up to 72 hours before or after the requirements date.

On June 30th you still do not have any stock, but your first requirement is on July 3rd.  The system calculates a days’ supply of 3 days.

Over the course of the month there are more requirements and receipts causing the receipt days' supply to change.

The receipt on July 1st is taken into account in the days' supply calculation because it occurs 48 hours too early and therefore lies within the tolerated 72 hours.

The receipt on July 11th is also taken into account because it occurs only 48 hours too late and therefore also lies within the tolerated 72 hours.

Because all requirements – taking into account the alert threshold for lateness of 72 hours – can be covered by receipts, the receipt days’ supply is 9.999,99.

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·  This graphic is explained in the accompanying text

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Late receipts that are not taken into account

In the location-dependent product master you have entered an alert threshold for earliness and lateness of 72 hours (3 days). Therefore, when calculating the receipt days’ supply, the system also takes into account receipts that occur up to 72 hours before or after the requirements date.

The receipt on July 1st is taken into account in the days' supply calculation because it occurs 48 hours too early and therefore lies within the tolerated 72 hours.

The receipt on July 11th is not taken into account because it occurs 144 hours later, more than the tolerated 72 hours and therefore cannot be used to cover the requirement on July 5th.

Therefore, the receipt days’ supply equals is 5 days. In other words, to cover the requirement, a receipt must occur within 5 days (+/- 72 hours).

This graphic is explained in the accompanying text

 

 

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