Backward Scheduling for External Procurement 

Use

For materials that are planned according to the MRP and forecast-based planning procedures, the requirement dates in the future are known. The materials must be available by these dates. The release date for the purchasing department is calculated during scheduling, that is, the date by which the materials must be ordered so that they are available for the requirements date. Therefore, the system starts with the requirements date and then schedules backwards to determine the release date of the purchase requisition.

 

 

For more information, please refer to the section Example of Backward Scheduling for External Procurement.

In MRP and forecast-based planning, the system always uses backward scheduling procedures to calculate the basic dates. Only if the start date that is calculated in backward scheduling happens to lie in the past, will the system automatically switch to forward scheduling.

If you do not want the system to switch to forward scheduling automatically, you can specify per plant in Customizing for MRP, in the IMG activity Parameters for determining the basic dates that the system is to continue the backward scheduling calculation even if the resulting start date lies in the past.

 

You control the availability check using general and SD-specific control features.

General Control Features

The following control elements need to be maintained in Customizing and in the material master record:

Strategy group

The allowed planning strategies (main strategy and further possible strategies) are combined in the strategy group. As of Release 3.0, the strategy group is specified in the material master record in the MRP 1 Screen. In Customizing, strategy groups are assigned, dependent on plant, to MRP groups. If the strategy group is missing in the material master record, it is determined on the basis of the MRP group, if it has been maintained.

Up to Release 3.0, the strategy group is determined on the basis of the MRP group

MRP group

The MRP group combines materials from the point of view of material requirements planning. This enables you to control planning for these materials in a particular way using, for example, the strategy group, consumption mode and planning period. You enter the MRP group in the material master in the MRP 1 screen. The strategy group is determined from the MRP group.

Planning Strategy

The planning strategy specifies the requirements type for planning and customer requirements. This represents the decisive control feature for the interaction between Production Planning and Sales and Distribution.

MRP type and item category

If no requirements type is found using the planning strategy, the system tries to determine a corresponding requirements type on the basis of the MRP type and the item category.

Until 3.0C, determination of the requirements type via planning strategy has taken priority. This is not always the best option, however, as the following example will show. A requirements type is determined for a material, which

causes availability to be checked against planning. In consignment stock processing, however, availability should be checked against stock. Until 3.0C the availability check had to be deactivated in these cases. As of Release 3.0C, you can determine how the requirements type is to be determined for each transaction by maintaining the Source field in Determination of requirement types using transaction in Customizing.

Requirements type

The various requirements are identified by their requirements type. The requirements type refers to the requirements class and its control features.

Requirements Class

The requirements class contains all control features for planning such as relevance for planning, requirements planning strategy and requirements consumption strategy. In addition, it is specified at a global level whether an availability check is to take place for the material in the sales and distribution documents on the basis of the ATP quantity (ATP = available to promise) and whether requirements are to be passed on. A finer degree of control can be obtained for sales documents using the schedule line category.

Control Features Specific to Sales and Distribution

The following SD-specific control features need to be maintained in Customizing:

Checking group

The checking group controls whether the system is to create indivdual or collective requirements in sales and shipping processing. In addition, a material block for the availability check with transfer of requirements can be set here. The checking group can also be used to deactivate the availability check. This option was created especially for the assembly order so that when the bill of material is exploded in the assembly order, the individual components, if necessary, can be classified as non-critical parts as far as procurement is concerned.

The checking group specifies in combination with the checking rule the scope of the availability check. It is proposed in the material master record on the basis of the material type and the plant, and copied into the sales and distribution documents.

Checking Rule

You use the checking rule to control the scope of the availability check for each transaction in sales and distribution. You also specify whether the check should be carried out including or excluding replenishment lead time. The individual checking rules define by transaction, which stock and inward and outward movement of goods should be taken into account for the availability check.

Schedule line category

You can control with the schedule line category whether an availability check and transfer of requirements should be carried out in the sales documents. The possible settings for this at schedule line level are dependent on the settings in the requirements class which is determined from the requirements type of the material.

Delivery item category

The delivery item category can be used to control whether an availability check takes place in deliveries.

Prerequisites

An availability check can only be carried out if the following prerequisites have been fulfilled:

The control elements described above for the availability check must be maintained in Customizing for Sales and the relevant assignments made to the sales transactions

The availability check must be switched on at requirements class level and - for the availability check in the sales documents - at schedule line category level

A requirements type must exist by which the requirements class can be found

A plant must be defined. It can either be proposed from the customer or material master record or can be entered manually in the document.

A checking group must be defined in the material master record on the Sales/plant data screen in the Availability check field

Global and Fine Control in Customizing

At the global requirements class level, the availability check can only be switched on in combination with the transfer of requirements. At schedule line level, the settings are proposed from the requirements class.

If the availability check is switched on at requirements class level, it can be switched off at schedule line level. However, you cannot switch on the availability check at schedule line level, if it is switched off at requirements class level. You can make this setting at schedule line level. But the system ignores it and the setting for the requirements class applies.

Also, at schedule line level when the availability check is switched on, the transfer of requirements can be switched off. For example, this makes sense for inquiries or sales information.

The settings specific to schedule lines for performing an availability check are only relevant for sales documents. In the shipping documents, the settings from the requirements class and the delivery item category are used. As with the schedule line category, the availability check can be switched off as required in the delivery item category.

Blocking Logic

There are two blocking concepts:

Material block

In Customizing, the Define material block for other users, step is used to determine, by checking group and transaction (order/delivery), whether a material master record should

be blocked for other users during an availability check. The block is set at material-plant level and remains in place until you save the sales document.

Material block with quantity transfer

For performance-related reasons, the only time when it makes sense to set the material block with quantity transfer is when it is common for several users to work on the same material simultaneously. If this is not the case in your organization, you can work with the conventional blocking logic at material-plant level.

In Customizing, the material block can be set with quantity transfer under Define checking group. If this block is active, the material is blocked only for the duration of the availability check when you create or change a sales and distribution document. Thus, it is possible for several users to process the same material simultaneously in various transactions without blocking each other. During the availability check, the material being used is blocked exclusively in the current plant as in a conventional block.

If another user tries to process the blocked material in the corresponding plant while the availability check is being carried out, the system tries five times to block the material exclusively for this other transaction with a pause of about 1 second between each attempt. If the fifth attempt is unsuccessful, the check is terminated and the transaction remains unconfirmed. To confirm the transaction, the user must call up the availability check again.

After completion of the check, the corresponding confirmed quantities are still blocked, but not exclusively. The material block is removed. The non-exclusive quantity block then supplies information to users working in other transactions, on the reserved quantities of the corresponding material being processed in the selected plant. The block entries are removed when processing is completed. If the transaction processed was saved, then the block entries were only removed after the relevant changes to the data base have been carried out.

You create a sales order for a material. During the availability check, this material is blocked. After the availability check is completed, the block is removed. The quantity reserved for this transaction is recorded in the blocking table. This information can be assessed by all others who are working with this material. If you save the order, the blocked entries are cancelled.

During manual backorder processing, a material with a quantity block is blocked exclusively so that an availability check for this material is no longer possible.

If both of the blocking options are active, the block with quantity transfer takes precedence.

 Types of Availability Check in Sales and Distribution

ProcessingThere are three types of availability check:_ Check on the basis of the ATP quantities_ Check against product allocation_ Check against planning The following SD-specific control features need to be maintained in Customizing:

_ Checking group

The checking group controls whether the system is to create individual or collective

requirements in sales and shipping processing. In addition, a material block for the

availability check with transfer of requirements can be set here. The checking group can

also be used to deactivate the availability check. This option was created especially for

the assembly order so that when the bill of material is exploded in the assembly order,

the individual components, if necessary, can be classified as non-critical parts as far as

procurement is concerned.

The checking group specifies in combination with the checking rule the scope of the

availability check. It is proposed in the material master record on the basis of the material

type and the plant, and copied into the sales and distribution documents.  It is specified in MMR in MRP3 screen, availability check tab.

_ Checking Rule

You use the checking rule to control the scope of the availability check for each

transaction in sales and distribution. You also specify whether the check should be

carried out including or excluding replenishment lead time. The individual checking rules

define by transaction, which kinds of stocks and inward – outward movement(receipts and issues) of goods should

be taken into account for the availability check.

_ Schedule line category

You can control with the schedule line category whether an availability check and

transfer of requirements should be carried out in the sales documents. The possible

settings for this at schedule line level are dependent on the settings in the requirements

class which is determined from the requirements type of the material.

_ Delivery item category

The delivery item category can be used to control whether an availability check takes

place in deliveries.

Requirements type

The various requirements are identified by their requirements type. The requirements

type refers to the requirements class and its control features. it is assigned to requirement class.

_ Requirements Class

The requirements class contains all control features for planning such as relevance for

planning, requirements planning strategy and requirements consumption strategy. In

addition, it is specified at a global level whether an availability check is to take place for

the material in the sales and distribution documents on the basis of the ATP quantity

(ATP = available to promise) and whether requirements are to be passed on. A finer

degree of control can be obtained for sales documents using the schedule line category.

 Replenishment lead time is only included in the check performed on the basis of theATP quantity. Prerequisites

An availability check can only be carried out if the following prerequisites have been fulfilled:

_ The control elements described above for the availability check must be maintained in

Customizing for Sales and the relevant assignments made to the sales transactions

_ The availability check must be switched on at requirements class level and – for the availability check in the sales documents – at schedule line category level

A requirements type must exist by which the requirements class can be found

_ A plant must be defined. It can either be proposed from the customer or material master

record or can be entered manually in the document._ A checking group must be defined in the material master record on the Sales/plant data

screen in the Availability check field  Configuring entries of the Availability CheckIMGàSDàBasic fncsàAvailability check and TORàAvailability checkàAvailability check with ATP logic or against planningàDefine checking groups

You can use SAP std checking groups of 01 for summarized reqts or 02 for daily reqts or u can create ur own.

The columns total sales and total deliveries are selection options whereby u can configure a checking rule to sum up reqts to post to MRP either individually or by day or week.

Column 5, Block qty; set this block if u want several users to be able to process the material simultaneously in different transactions without blocking each other. The No Check indicator is used when u want a material to not be relevant for an ATP check.

Defining a material block for other users. The Block checkbox is an indicator that enables u to block the particular material from being checked for availability if it is already being checked at the same time by another user.Defining the default value for checking groups. However should no entry exist for the checking group in the material master record, one can set a default value per material type and plant.Controlling the availability check. In this section, u tell the system what stock on hand and what inward and outward movements of stock it must take into account when performing the availability check. These settings are based on the checking group that is assigned to the material master record and the checking rule that is predefined and assigned to the sd transaction. The carry out control for the availability check must be maintained for both the sales order and delivery.  

TOR

IMG à SD à Basic fncs à Availability check and TOR à TOR

A line item in the sales order creates a schedule line. The schedule lines in the sales order transfer the requirements through to MRP. You can select the docs on which you want the TOR to happen. For ex, not for quotations.

The TOR aims to ensure the ordered materials are available for the requested delivery date. The TOR can be set for individual or for collective requirements (materials masteràsales/plant view).

  The TOR is dependent on the following data:

The reqts type, reqts class, checking group and schedule line category.

The reqts type and class are determined in the strategy group (material masteràMRP3)

 For TOR to be carried out, a few criteria need to be met:

Plant assigned to line item level, schedule line category should be switched on at TOR, TOR must be switched on at the reqts class level, checking group must be defined and allocated to the material master record (sales/plant view in the availability check field)  The reqts class is the controlling factor for the availability check and the TOR for all sd types. Configuring the TOR:

1)      Use std 041 reqts class or copy and rename it. Use the indicators to select if this reqts class must carry out an availability check and/or a TOR.

2)      Define the reqts types. A reqts type is allocated to a single reqts class and not vice versa. It is based on the item category and the MRP type of the material.

3)      Assign the rqts type to the relevant item category in the sales order and the MRP type found on the material master record.

You can select an alternative search strategy where u assign the reqts type to item category and MRP type. Can select source as 0, 1 or 2. (1 = Item type and MRP type strategy).

4)      The TOR and Availability check can be selected/de-selected at the schedule line category level.

5)      Block qty confirmation in delivery blocks. This is used to block the reservation of the TOR from MRP.

6)      Maintain requirements for TOR. Requirements can be used to determine that the TOR to MRP is not carried out unless a number of conditions are met. Availability Overview = CO09 à order qty, sd doc no, item no, requirements class.

Stock requirements list = MD04 à sd no or dly no, line item, schedule line placing the demand

Stock overview = MMBE à total stock per company, then plant followed by storage location, and finally a breakdown per batch.

Order Date

 Date on which the sales order is entered. System proposes the current date by default.

Material Availability Date

 The date on which the material must be available. On the material availability date, the vendor

must start the activities relevant for delivery, such as picking and packing the goods. The

material availability date must be sufficiently early enough so that the goods are prepared by the

loading date.

Transportation Planning Date

 We must arrange transportation by this date, so that the delivery can be sent to the customer.

The date from which the organization of goods transport must begin. The transportation planning

date must be selected early enough so that the transport is available on the loading date to load

the goods.

Loading Date

Picking and packing must be completed by this date so that the goods are ready for loading.

Goods Issue Date

 Goods must physically leave the shipping point by this date. The date on which the goods must

leave the company to arrive at the customer location in time.

 

Delivery Date

Customer should receive delivery of the goods by this date. The date on which goods are to

arrive at the customer's premises. Example: The delivery date can be the delivery date

requested by the customer (desired delivery date) or the date confirmed in the vendor's order

acknowledgment or shipping confirmation (confirmed or acknowledged delivery date).

Times:-

Pick/Pack Time

 Difference between the material availability date and loading date.

Transportation Lead Time

 Number of days required for organizing a shipment for an item to be delivered.

Loading Time

 Difference between loading date and goods issue date.

Transit Time

 Number of days required for delivering an item from your company to the customer via a certain

route.

How do we View Availability Situation?

Run Transaction: CO09

Enter Plant & Checking Rule, against which the Availability is to be checked. For Sales Order

Checking Rule = A, Delivery = B, Back Order = BO

 

In this screen, we can see:

Availability Checking Group (Avail Check): 02

Check Rule : A

End Lead Time Refers to the end of Replenishment Lead Time. If that is not included in the

Configuration, then this field is not visible.

Totals Display:** Receipts = Sum of all +ve Quantities in Rec./Reqd qty Column

(Leave out the last row, MRP Element 001, since it is a total)

These are all the Planned Incoming Movements

Issues = Sum of all -ve Quantities in Rec./Reqd qty Column

These are all the Planned Outgoing Movements

Confirmed issues = Sum of all (+ve) Quantities in Confirmed Column

These are the confirmations against ATP.

When is Availability Check Triggered?

While creating a Sales Order, Production Order, Delivery, etc. Below is a screen from Sales Order.

At the bottom is a button for Check Material Availability. Also while creating the order, if the

Availability situation cannot meet the requested delivery date, the system goes to Availability

screen automatically. (Discussed later)

Run Transaction: VA01

How we arrive at a Confirmed Delivery Date?

Below is the logic the system uses to check availability:Using the Scheduling data from Delivery & Transportation Scheduling, the system does the

backward calculation from the Requested Delivery Date. This is used to arrive at Material

Availability Date.

On the Material Availability Date, system checks the Available Qty, as seen in CO09 in column

Cum. ATP Qty. If the Available Qty is > than Required Qty, Requested Delivery Date is

confirmed. Otherwise,

System moves into the future till it finds the required Available Qty. The new date is then the

new Material Availability Date.

On getting the confirmed Material Availability Date, system does the Forward Scheduling to

arrive at a Confirmed Delivery date.

Backwards Scheduling

Control of Availability Check

 

Forward Scheduling

 

Result of Availability Check: Some Sample Scenarios

Above is the Availability Screen as seen in Sales Order. It has following Buttons:

One-time delivery

In the results of Availability, we have 3 options to choose from. This is Case 1, when we can

confirm the Customer's Requested delivery Date. The details of this are visible in the first sub

screen below.

Complete dlv.

This is Case 2, when we can confirm the Customer's Requested complete delivery at a future

Date. The details of this are visible in the second sub screen below.

Delivery proposal

This is Case 3, when we can confirm the Customer's Requested delivery in partial quantities at

future dates. The details of this are visible in the third sub screen below.

Continue

If we select one of the above options, the same gets saved in the ATP results. Otherwise, we can

select this button. In that case, system leaves the ATP screen without saving the ATP results.

Case: Confirmation on Requested Delivery Date

Case: Confirmation after Requested Delivery Date (Complete Delivery)

Case: Confirmation after Requested Delivery Date (Partial Delivery)

See the screens below corresponding to this situation.

The first screen shows the Availability (CO09) Overview. We have an incoming PO on 19 Jan.

!image034.jpg!In the second screen

We have created a SO (VA01) on 09 Feb, with requested Delivery date for 09 Feb.

Now we change the Availability situation, by changing the PO Date to 12 Feb. See the screens below corresponding to this situation.

The first screen shows the Availability (CO09) Overview. We have an incoming PO on 12 Feb. See

the new Cum ATP qty. date wise accordingly.

!image038.jpg!In the second screen

We have created a SO on 09 Feb, with requested Delivery date for 09 Feb.

See that the Delivery got staggered according to the new Availability situation.

Case: Confirmation after Requested Delivery Date (Replenishment Lead Time)

In the screens below, we have simulated the RLT.

In the first scenario RLT is not activated, see below: 'Check without RLT'. The system considers

only the confirmed inward movements. So out of 500 only 21 is confirmed.

See IMG Guide > SD > BF > AC & TOR > AC > AC with ATP > Control of Availability Check

See VA01

 

In the second scenario RLT is activated, but corresponding data in material master is not

maintained. Material is procured In-House (E), but In-house Production time (1st screenshot) &

RLT (2nd screenshot) are not maintained. The system assumes both these times as Zero. So,

complete 500 are confirmed immediately. See MM01

 

 In the third scenario RLT is activated, corresponding data in material master is maintained.

Material is procured In-House (E), In-house Production time (10 days) & RLT (not maintained).

The system confirms 21 on basis of incoming material. Rest 479 is confirmed after 14 days. This

is because 10 working days for in-house production + 4 holidays (Sat-Sun).

 

 

In the fourth scenario RLT is activated, corresponding data in material master is maintained.

Material is procured In-House (E), In-house Production time (10 days) & RLT (20 days). The

system confirms 21 on basis of incoming material. Rest 479 is confirmed after 14 days. This is

because 20 working days for in-house production + 8 holidays (Sat-Sun).

What Configuration & Data do we need?

Controlling Elements:-

Requirements Type

Requirements Class

Schedule Line Category

Delivery Item Category

Checking Group

Checking Rule

Scope of Check

Strategy Group

Partial Delivery Agreement

Replenishment Lead Time

Material Master Data:-

MRP 1 > MRP Group

MRP 2 > Planned Delivery Time

MRP 2 > GR Processing Time

MRP 3 > Checking Group for Availability Check

MRP 3 > Strategy Group

MRP 3 > Total Replenishment Lead Time 

Scheduling Data:-

Transit Time

Loading Time

Pick/Pack Time

Transportation Planning Lead Time

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