SAP Note 25388 - MD01, MD02, MD03: Rescheduling proposals: Docum.

Symptom:

In the rescheduling check, the system checks - starting with the first requirement - whether all requirements can be covered by firmed receipts (purchase orders, production orders, firm planned orders, firm PReqs, firm delivery schedules). If this is the case, the firmed receipt is assigned a corresponding rescheduling proposal by materials planning, and a new order proposal (planned order, PReq, schedule line) is not created for the requirements.

The rescheduling check is carried out from the planning date up to the end of the replenishment lead time (from the material master) + rescheduling horizon.

If the firmed receipt is dated before the requirements, then the receipt is not needed until later; the rescheduling check is always carried out this way. Exception message 15 and the rescheduling proposal are then displayed.

If a requirement is not covered by a firmed receipt before the requirements date, then the system searches for firmed receipts that are further in the future and meet the following preconditions:

• The firmed receipt is within the rescheduling horizon. The rescheduling horizon is set in Customizing for the MRP group (Transaction OPPR, Table T438M). A default value can be predefined in the Customizing of plant data (Transaction OPPQ, Table T399D).
  

• The firmed receipt (the MRP element) participates in the rescheduling check. You can set which MRP elements participate in the rescheduling check in the Customizing of the plant data (Transaction OPPQ).
  

If an appropriate firmed receipt is found, it is assigned exception message 10. The exception messages can be changed in Customizing (Transaction OMD3 or table T458A). Thus, you can differentiate from the standard setting.

The rescheduling check is carried out before the actual materials planning, that is, before creating new order proposals. The rescheduling check for moving and for the cancelation check is carried out over the entire time axis. The rescheduling check for shifting forward is carried out over the area of the rescheduling horizon. The planning horizon has no influence on the creation of rescheduling proposals. It is therefore possible for rescheduling proposals to be carried out outside of the planning horizon. This is certainly very useful if requirements within the planning horizon are to be covered.

I would like to explain the following points in more detail:

1. Requirements planning creates a new order proposal (planned orders, order requirements, or delivery schedules) although sufficient firmed receipt elements (firm planned orders, purchase requisitions, or schedule lines, production orders, shipping notifications, and purchase orders) exist.

2. In the requirements planning run, a new order proposal was created for a particular date, although on this date, a firmed receipt element with the same quantity already exists. However, this firmed receipt element has been given a reversal proposal in the planning run.

3. A requirement which cannot be covered by the current warehouse stock is in the past. Also in the past is a firmed receipt which covers this material shortage. The receipt, however, is after the material shortage. Materials planning responds in this case as follows: Cancellation proposal for the firmed receipt element and creation of a new order proposal which has a start date in the past.

4. There is a balanced stock/requirements situation, that is, for every requirement there is an appropriate receipt element. The receipt elements at the start of the time axis are firmed receipts, thus for example, production orders, purchase orders, firm planned orders, PReqs, or schedule lines. Now, a new larger requirement is added at the start of the time axis. As a result, new order proposals are created at the end of the time axis. The entire lot size determination becomes chaotic. Suddenly, there are more receipt elements than requirements for a lot-for-lot order quantity.

5. At the start of the time axis, there is a requirement which is not covered by an order proposal of materials planning. Although the material was replanned with MD01 or MD02, you cannot find a receipt element near the requirement which would be suitable to cover this requirement. Negative quantities are also displayed in MD05/MD06 for the available quantity.

6. The MRP controllers search for materials with exceptions using Transaction MD05/MD06 via exception groups (Customizing exception groups) in order to intervene manually if necessary. In this case, they are flooded by materials with rescheduling proposals. In most cases, the requirements date and receipt date are only one or two days apart.

These rescheduling proposals are often viewed as unnecessary. How can you avoid these rescheduling proposals in order to reduce the order/operation pool of the MRP controllers ?

7. A requirement could be covered by a receipt reservation which is further in the future. Instead, a new order proposal is created. Thus, the receipt reservation does not participate in the rescheduling check.

8. A rescheduling proposal 15 (move) is created for a firmed receipt element at the start of the time axis. On the other hand, a rescheduling proposal 10 (forward shift) is created for a later firmed receipt element.

How can you reach such a situation where the effect of both rescheduling proposals might be balanced?

9. You get a material with an assembly order and create an assembly order directly from a sales order. However, material requirements planning does not create a planned order for the sales order. The problem can occur if the material is scheduled deterministically. This may also be useful for materials which are obtained with assembly orders, for example to consider different requirements (no sales orders).

10. A distribution key is used for receipts (for example, planned orders). A planned order of 100 pieces is distributed as a result, for example Monday to Friday (in each case, 20 pieces). If you now firm the planned order, a subsequent planning run creates additional receipts.

Additional key words

MD01, MD02, MD03, MD04, MD05, MD06

Cause and prerequisites

1. The firmed receipt elements are later than the requirements and the rescheduling horizon is set too soon. If the firmed elements are outside of the rescheduling horizon, you can not use these as resources.

2. The rescheduling check is carried out before the lot-size calculation and has no information on the lot-sizing procedure selected. In Customizing for the period lot-sizing procedure, you can use the scheduling indicator to determine when the availability date of an order proposal is to be - at the requirements date, the start of the period, or the end of the period. If the availability date is at the end of the period, then all new requirements within the period are covered by one order proposal that is not available until the end of the period. If this receipt element is firmed (for example, by conversion to a production order or a purchase order), and if the requirements do not also lie at the end of the period and if the requirements lie outside the rescheduling horizon, then the system recognizes a shortage within the period and creates a new order proposal. The firmed receipt element is used to cover following requirements. If no further requirements exist, then the system flags the firmed receipt element with a reversal proposal 20. The availability date of the new order proposal is again set to the end of the period so that now two receipt elements exist for this date - one that has newly been created and one firmed with a reversal proposal.

3. The firmed receipt element was not included in the rescheduling check. This receipt element could not, therefore, cover the requirements before it. You can set which firmed receipt elements are taken into account in the rescheduling check in Customizing of the requirements planning plant parameters (table T399D).

4. The new requirements are near in the future. In-house production times are no longer sufficient to cover them. The firmed receipts (production orders which it is hoped are already in production) therefore have to be accessed. The rescheduling check therefore creates rescheduling proposals for the firmed receipts - provided that it was set in the Customizing of a plant data that these firmed receipt elements participate in the rescheduling check.

If these rescheduling proposals are followed, then the new requirements can be covered by the firmed receipts with the rescheduling proposal. As a result, the requirements originally covered by the receipt elements with the rescheduling proposal must be covered elsewhere. Materials planning creates new order proposals for this. If the new requirements are larger than the first firmed receipt, then rescheduling proposals are created on the same date for several firmed receipts. Now several firmed receipts cover a requirement. Materials planning now creates a new order proposal for each of the remaining requirements for each requirements date for the lot-for-lot order quantity. There are then more receipt elements than requirements elements.

Important: There is no fixed relationship between requirement elements and receipt elements. For firmed receipts, only the date determines which requirements are covered by which receipt element. The lot-sizing procedure is insignificant here.

5. Further in the future, there is a firmed receipt (in Transaction MD04/MD05/MD06, you might have to scroll many pages forwards). This is first used for covering requirements. Only if the quantity from the firmed receipt is no longer sufficient, does materials planning create new order proposals. Thus, the first requirement is covered by the first firmed receipt. In this case, it is not relevant whether the availability date of the firmed receipt lies before or after the requirements date. It is also unimportant whether further requirements lie between the first requirement and the firmed receipt. In Transaction MD05/MD06, the firmed receipt is assigned a corresponding rescheduling proposal.

6. In the Customizing of MRP groups, you can set tolerance values for the rescheduling check. Default values can be set using plant parameters. An exception message is created only if the firmed receipt lies more days after the requirement than the number of "comparison value for rescheduling shift" or more days before the requirements date than the number of "comparison value rescheduling move forward".

7. If the availability date of the firmed receipt is within the comparison values, then an exception message is not created and the material is not displayed in Transaction MD06 when accessing via MRP controller and exception group (provided that no other exceptions were calculated).

8. A dependent reservation representing a receipt (manufacture of co-products) normally cannot be rescheduled independently. This can only be done by rescheduling the superceding production order. Therefore, the dependent receipt reservation does not participate in the rescheduling check.

Since Release 3. 0A, stock transfer reservations always participate in the rescheduling check.

Manually created receipt reservations participate in the rescheduling check since Release 3.0A. The prerequisite for this is that either the production orders or purchase orders also participate in the rescheduling check (Customizing of plant parameters for requirements planning).

9. A safety stock is set in the material master for a material and there are outstanding requirements for the material in the past. A firmed receipt element in the past could now cover the requirements in the past, but it is assigned a rescheduling proposal to cover the FIRST requirement on the list, namely the unavailable safety stock. This requirement has the respective current date as the date. The firmed receipt element in the past is now given rescheduling proposal 10 (move) because the material shortage due to the missing safety stock is not as far in the past.

A firmed receipt which is expected later (for example, on the current date) now covers the NEXT requirement on the list, that is, the open requirements in the past. This receipt element is given rescheduling proposal 10 (move forward).

The problem is due to the fact that the missing safety stock represents a requirement for the current date, but this requirement is sorted at the beginning of the time axis.

The problem only occurs if there are requirements in the past. The respective firmed receipt elements always need special processing.

10. Requirements planning does not know the link between receipt and and outward movement elements. This also applies to the assembly order of a sales order. The sales order and assembly order are sorted according to date and inserted in a separate planning section. If the requirement date of the sales order is prior to the basic date of the assembly order, a rescheduling proposal is created if the assembly order participates in the rescheduling check. If this is not the case, that is, the assembly order does not participate in the rescheduling check, a new planned order is created to cover the sales order.

11. The rescheduling horizon is set too short or the firmed receipt element is set in such a way in Customizing that it does not participate in the rescheduling check. The rescheduling logic does not recognize that it is a distributed planned order in which the receipt date is decisive in ensuring that the relevant requirements are covered by the distribution period.

Solution

1. Enter a longer rescheduling horizon for the MRP group of the material. A default value can be entered in the plant parameters for requirements planning.

2. Use a longer rescheduling horizon. For period lot-sizing procedures, with the availability date at the end of the period, this horizon should be at least so long so that all requirements lie within it.

3. In the Customizing of plant data, it is best to activate the rescheduling check for all firmed receipt elements.

4. This behavior is intended. There is no solution.
Pay attention to the rescheduling proposals. These can provide valuable information on when a manual intervention is necessary.

5. Try to firm the receipt element as late as possible or to generate firmed receipts. This ensures that materials planning adjusts the receipt elements to the current requirements each over a long period of time. It also prevents materials planning from trying to cover requirements with firmed receipts that are too far in the past or future.

You firm an order proposal by making manual changes. For planned orders, a simple "posting" is enough without having to change any data.

For firm order proposals, "/*" is displayed at the end of the planned order number or purchase requisition number in MD05/MD06 as well as in MD04.

If special company-internal reasons make it necessary to firm a receipt element early, or to create a firm receipt element, then try to do this in a separate planning section (individual customer requirements).

In the Customizing of the planning group table, you can set the rescheduling horizon. Default values can be set in the Customizing of plant data. Firm receipts outside the rescheduling horizon do not participate in the rescheduling check. This also prevents rescheduling proposals over a long period. If, however, the firmed receipt moves into the rescheduling horizon, then materials planning immediately covers the first requirement that is not covered by earlier firmed receipts.

6. Set suitable comparison values in the Customizing of the planning group table or plant data.

7. No solution. If stock transfer reservations or manually created reservations also participate in the rescheduling check in a 2.2 release, then the modification XXXXXX given below can be installed.

8. No solution.

9. If you process assembly orders and you plan the material requirements, make sure that the rescheduling horizon is long enough.

10. Use a rescheduling horizon and set in Customizing that the firmed receipts participate in scheduling.