Outlining Availability Check in Detail

To consolidate your understanding of the ATP check, here is a summary of the most important points:

• The ATP check is successful if a sufficient (cumulated) ATP quantity is available on the material availability date.

• The scope of the ATP quantity is defined individually for each company based on the operation or product (scope of check).

• The basic check level is at plant or storage location level.

• The check can be carried out regardless of whether the replenishment lead time is used.

• The ATP check in SAP S/4HANA is accurate to the day.

• Issues always try to consume the most recent receipt first.

• When the check is carried out, cumulated requirements and confirmed quantities can be taken into account.

The type and scope of the ATP check is defined in Customizing for availability control. This defines the ATP quantity calculation and the level of the check, and determines whether the ATP check is carried out with or without the replenishment lead time.

The availability control depends on the material, the material group, and the operation. The checking group is one feature of determining the availability check control. For the ATP check, materials are grouped using the checking group, whereby a specific checking group is assigned to the required materials in the material master. New checking groups can be defined in Customizing if necessary.

The second feature for determining the availability check control is the checking rule. This is used to distinguish operations in terms of the ATP check. The assignment of document type and checking rule is hard-coded in the Sales and Distribution application. In general, checking rule A is assigned to the sales document and checking rule B is assigned to the delivery document.

The basic concept of the check based on the ATP quantity is summarized as follows: the requirement date of incoming requirements (for example, customer requirements or component requirements in manufacturing) is checked against the cumulated ATP quantity. If the ATP quantity for the requirement date is available, the requirement can be confirmed. At the same time, a confirmed requirement reduces the cumulated ATP quantity. The quantity is therefore reserved for the requirement and is not available for other requirements.

The stocks and stock changes that are taken into account when the ATP quantity is calculated and the availability is checked depend on the scope of the check. The document processor can display the check scope of a document when processing the document. This is defined in Customizing.

In the availability check control, you also define the scope of the check. That is, you specify which stock segments, planned requirements, and planned receipt elements are included in the ATP quantity calculation.

The following elements can be included in the availability check:

• Stocks: unrestricted-use stock, safety stock, stock in transfer, stock in quality inspection, and blocked stock.

• Receipts/issues: purchase orders, purchase requisitions, planned orders, production orders, reservations, dependent reservations, dependent requirements, sales requirements, and delivery requirements.

Receipts in the past: If planned receipts are included in the ATP quantity calculation, the following situations may arise. At present, there may be planned receipts that were expected in the past. These receipt elements should already have been added to stock. However, they are still planned receipts with a planned receipt date in the past. In Customizing for the availability check control, you can now decide whether this receipt element is to be included in the ATP quantity calculation. In either case, you can activate an additional warning message for the user.

For operations that generate special stocks (such as make-to-order production, consignment processing, or returnable packaging processing), availability is checked against the special stock using the specified scope of the check, in conjunction with the respective special stock indicator from the requirement class.

Since various, operation-based scopes of checks can be defined, they must be consistent along the process chain. If, for example, the checking rules dictate that the availability check in sales documents is to include both sales and delivery requirements, but that the availability check in deliveries is to include delivery requirements only, there is a danger that quantities already reserved by sales documents may be displayed as available for the availability check of deliveries. As a result, there may be a backlog of sales documents in some cases.

In sales documents, availability is checked in the plant of the order item. The plant is usually determined automatically (location determination) based on the master data. Any master data in which the delivery plant can be defined is accessed in the following sequence:

1. Customer-material info record (detailed view).

2. Customer master record of the goods recipient (Sales Data: Shipping tab page).

3. Material master record (Sales: Sales Org. 1 tab page).

4. If you enter the delivery plant manually during order processing, your entry will overwrite the default value for location determination.

If you enter the delivery plant manually during order processing, your entry will overwrite the default value for location determination.

The storage location is not automatically determined in sales documents. The availability check of sales documents is therefore specific to a storage location, only if the storage location is specified with the document item either manually or by configuring the system.

Availability for deliveries is checked at the level of the delivery plant or storage location of the delivery item if the check at storage location level is active. The storage location can be and generally is determined automatically in deliveries.

Depending on the attributes of the requirement (plant, storage location, batch, storage location/batch), availability is checked at different levels. For example, if a requirement applies only to a plant, it is sufficient to restrict the stocks, receipts, and issues to plant view. However, if the issue refers to a batch or storage location, batch and storage location stocks must be included along with the plant stock. For example, if a batch is specified, the check is carried out on two levels: first against the batch and then against the plant stock. If a batch and a storage location are specified, the check is carried out on four levels: first against the batch storage location, then against the batch, then against the storage location, and finally against the plant stock.

SAP Customizing Implementation Guide: Sales and Distribution → Basic Functions Availability Check and Transfer of Requirements → Availability Check Availability Check with ATP Logic or Against Planning → Carry Out Control For Availability Check

In Customizing for the availability check control, the check at storage location level can be deactivated in the Storage Location Inspection area. If the No Stor. Loc. Inspectn indicator is not set, availability is checked at the level of the storage location. This assumes, however, that the requirement contains storage location information. If this is not the case, the check is carried out at plant level only. The requirement must always contain plant information. If the No Stor. Loc. Inspectn indicator is set, availability is checked at plant level. This is the case, even if the requirement contains storage location information.

The replenishment lead time is the time required to order or produce the requested material and to provide it in the company. In the availability check control, you specify whether the ATP check is to be carried out with or without the replenishment lead time.

Availability is checked only until the end of the replenishment lead time. If the material availability date for the item when calculated from the current date is outside the replenishment lead time, the item can always be confirmed. In this case, the system assumes that any required quantity can be confirmed up to the material availability date and considers the goods to be available. They can therefore be contractually promised to the customer. If the material availability date is within the replenishment lead time, checks are carried out on the basis of the ATP quantity. The requirement is confirmed at the latest at the end of the replenishment lead time. The availability check that uses the replenishment lead time only produces meaningful results if you plan in regular intervals. (For single and daily requirements, you should plan on a daily basis. For weekly requirements, you should plan on a weekly basis). The confirmed quantities are then compared with receipts. This is necessary because the delivery date of an order that was confirmed on the day before the replenishment lead time already lies within the replenishment lead time on the current day, and thus leads to a shortage. This shortage could then prevent the delivery from being created, for example.

If the replenishment lead time is not taken into account during the availability check, the system carries out an unrestricted availability check.

The replenishment lead time is the time required to procure or produce the material in full using all BOM levels. The system calculates the replenishment lead time using specific times that you define in the material master record and in Customizing. Depending on the procurement type, it can be calculated from different time periods. So that the replenishment lead time can be calculated correctly, you must enter the necessary times in the material master record and in Customizing.

For materials produced in-house, the following options are available. If the Total RLT field (MRP 3 View) is maintained, the time maintained in this field is used for the availability check. If the Total RLT field is not maintained, the system reads the in-house production time (MRP 2 view) and, if available, the goods receipt processing time (MRP 2 view) and interprets the total of these two times as the replenishment lead time for the availability check.

For materials procured externally, it is not useful to maintain the Total RLT field. For external procurement, the total of the purchase processing time (Customizing: Materials Management → Purchasing → Purchase Requisition → Processing Time), planned delivery time (MRP 2 view), and goods receipt processing time (MRP 2 view) is always interpreted as the replenishment lead time for the availability check.

Checking availability without taking into account the cumulated, confirmed quantity or requirement quantity (shortage check) may lead to overconfirmation. Based on the material availability date of the sales order in the past, the system checks whether there are receipt elements with an ATP quantity that is still free. If there is a planned receipt based on the material availability date of the sales order in the past, it is used to confirm the order requirement. If the planned receipt is then postponed to any date after the confirmation date, the sales order confirmation is retained even though there is not enough stock to cover the requirement. This is because changing the receipt does not automatically change the order. A new order created in this situation might also be confirmed because of the postponed receipt and thus lead to overconfirmation. To correct this, you can execute a planning run, reschedule, or process a backorder. Since these functions require a lot of time, it is possible that orders whose entry dates indicate that they cannot be delivered are actually delivered.

The shortage check prevents the scenario described above from occurring since when it is active, the system not only confirms past receipt elements on the basis of the available ATP quantity, but also checks whether the total requirements and confirmations exceed the total stock and receipt elements. If confirming a new requirement means that the total number of requirements or confirmations in the system exceeds the stock and receipt elements, no confirmation can be made as part of the ATP check. In our example, the second order cannot be confirmed.

You can activate the shortage check in Customizing for the checking group. The following options are available:

• No cumulation = No shortage check

• Check taking into account the cumulated, confirmed quantities: When calculating the cumulated ATP quantity, the system takes into account the total of all previously confirmed quantities. This means that new sales orders can be confirmed only if the total receipts exceed the confirmed quantities. We recommend that you work with cumulated requirement quantities when you create sales orders (checking group, field Accumul. parameter 2 or 3).

• Check taking into account the cumulated requirement quantities: When calculating the cumulated ATP quantity, the system takes into account the total of all requirement quantities open to date. This means that new sales orders can be confirmed only if the total receipts exceed the total requirement quantities. We recommend that you work with cumulated, confirmed quantities when you change sales orders (checking group, field Accumul. parameters 1 and 3).

• In addition, an information message can be activated to inform the user about the shortage situation (checking group, field Response, parameter 1).