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APO-PPS-SCF: Detailed Scheduling Strategies and Scheduling Functions ( RELNAPO_30A_SP1_PPS-SCF1 )

APO-PPS-SCF: Detailed Scheduling Strategies and Scheduling Functions ( RELNAPO_30A_SP1_PPS-SCF1 )

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APO-PPS-SCF: Detailed Scheduling Strategies and Scheduling Functions

Use

As of Release 3.0A (First Customer Shipment and Support Package 1), the following new and changed functions are available for the Detailed Scheduling strategies and for scheduling in Production Planning and Detailed Scheduling:

Replacement strategies in the strategy profile

Up until now, the strategy profile contained only one strategy, that is, one line of strategy settings with which you specify the rules and defaults by which the system should schedule and reschedule an operation or order. If the system did not find a scheduling date using these strategy settings, the system terminated the scheduling in the DS planning board. When creating an order in the APO system, the system tried, in this case, to execute scheduling using the strategy profile that you entered as an Emergency strategy in Customizing for the Maintenance of global parameters and default values.

As of Release 3.0A (FCS + SP1), you can define several strategies in the strategy profile, that is, several lines of strategy settings. If the scheduling or rescheduling is unsuccessful using one of the strategies, the system can switch to the next strategy, and so on. You specify the following in the strategy profile:

  • Which strategies in the strategy profile the system is allowed to use (you do this by setting the indicator for the allowed strategy to active)
  • In which sequence the system should use the active strategies (you do this by numbering the strategies)

The active strategy with the lowest number has the highest priority. The system uses this strategy first. If this strategy is not successful, the system uses the active strategy with the next number in the sequence, and so on. If the system cannot execute scheduling or rescheduling with any of the strategies, it does not schedule or reschedule.

Due to the fact that you can now maintain replacement strategies in the strategy profile, as of Release 3.0A (FCS + SP1) there are no longer emergency strategies in Maintenance of global parameter and default values.

Setting strategies using pushbuttons

As of Release 3.0A (FCS + SP1), you can also make selected strategy settings during interactive scheduling using pushbuttons.

Strategies for scheduling orders

As of Release 3.0A (FCS + SP1), you can specify in Customizing for Production Planning and Detailed Scheduling under Maintain global parameters and default values , which strategy profile the system uses for scheduling an order:

  • If an order is transferred via a BAPI into the APO system
  • If an order from Supply Network Planning is converted to an order for Production Planning and Detailed Scheduling

Setting the maximum run time for scheduling

In complex scheduling situations in which the system must consider many constraints and dependencies, the time necessary for scheduling can be very long. The system has internal settings which terminate scheduling after a fixed number of scheduling steps (corresponding to a maximum runtime of approximately 10 minutes). Up until now, you could set, according to user, an alternative runtime for scheduling in user maintenance using the SET/GET Parameter /SAPAPO/CDPS_TIMEOUT. The maximum runtime relates to the calling up of one scheduling run, that is, to the scheduling of all objects that you selected for scheduling, including the dependent objects. If scheduling is terminated after reaching the maximum runtime, all objects entered for scheduling are not scheduled or rescheduled.

As of Release 3.0A (FCS + SP1), you set the maximum runtime for scheduling in the strategy profile. If you do not enter a value here, or enter 0, the runtime is limited to the number of scheduling steps set internally in the system. Therefore, the possibility of setting the runtime using the SET/GET parameter no longer exists.

Default dates for rescheduling operations

As of Release 3.0A (FCS + SP1), the following changes apply for the default dates for operations:

  • In the DS planning board, you can not only specify the desired scheduling date for an operation using Drag&Drop, you can also enter the date specifically. Starting from the desired date you entered, the system searches in the planning direction for a scheduling date for the operation. If you want to use this option, choose in the strategy profile, in the screen section Desired date, the Date entered option.
  • In the strategy profile, there is the new Desired date screen section, in which you can explicitly choose between the various options for the desired scheduling date for an operation (Current date, Earliest date and Date entered). The Schedule at the earliest possible time indicator , with enabled you, up until now, to choose between scheduling at the current date and scheduling at the earliest possible time, no longer exists.

Considering the validity period of an order

As of Release 3.0A (FCS + SP1), you can set in the strategy profile whether the system should consider the validity period of an order when scheduling and rescheduling the order. The system determines the validity period of an order when exploding the iPPE or the production process model. When determining the validity period, the system considers for the order that was created on the basis of an iPPE, the validity periods for the iPPE itself, for the components and for the activities. For an order based on a production process model, the system considers the validity periods for the order products and for the components.

You have the following options:

  • Consider the validity periods
If you choose this option, the system must consider the validity periods for order to be scheduled or rescheduled as well as for the dependent orders that are linked via pegging relationships to the order (component orders and supplied orders). It is not possible to schedule orders outside of the validity period.
  • Only consider validity periods for dependent orders
If you choose this option, the system does not have to consider the validity periods of orders to be scheduled or rescheduled; the order can therefore be scheduled outside of its validity period. However, the validity period must be considered for the dependent orders (assuming you have specified in the strategy profile that the pegging relationships are to be considered).
  • Do not consider validity periods
If you choose this option, the system does not have to consider any validity periods.

If the validity period of an order is violated during scheduling or rescheduling, a corresponding message is issued. In the order view, the system executes a plan explosion with the production process model or the iPPE that is valid at this point in time.

Planning mode for dependent operations

Up until now, the planning mode that was specified in the strategy profile was valid for all resources affected by scheduling or rescheduling. If you had set the planning mode Insert operation, and you rescheduled an operation to a resource, then the operations at the other resources affected by the rescheduling were also rescheduled with the planning mode Insert operation. There was no distinction made between scheduling at the selected resources and scheduling at the dependent resources at which there were dependent operations (Dependent operations are operations that have to be rescheduled as a result of scheduling or rescheduling at the selected resources because relationships have to be maintained).

As of Release 3.0A (FCS + SP1), you can set your own planning mode for rescheduling dependent operations at dependent resources the planning submode. You use the planning submode to specify how the system schedules the dependent operations at the dependent resources. The following planning submodes are available:

  • Scheduling dependent operations according to the planning mode
Here the system schedules at the dependent resources with the same planning mode as at the selected resources. If, for example, you have set Insert operation as the planning mode for the selected resources, the dependent operations at the dependent resources are also rescheduled using Insert operation.
  • Deallocate dependent operations
Here the system deallocates the dependent operations at the dependent resources; that is, the dependent operations are given the status deallocated and are no longer loaded onto the resources.
This planning mode is recommended when you have defined various planners responsible for resources in various work areas. A change in the schedule in one planning area does not automatically lead to a rescheduling of dependent operations at the resources in another planning area. Instead, the dependent operations are removed from the schedule.
  • Scheduling dependent operations infinitely
Here the system reschedules the dependent operations at the dependent resources infinitely, that is, without considering the current resource load.

Skipping fixed operations

Up until now, the system could not shift an operation, which had to be rescheduled, over a fixed operation. In this case, the system terminated the rescheduling of the operation. As of Release 3.0A (FCS + SP1), the system can shift operations to be rescheduled over fixed operations.

Example: You have chosen the planning mode Insert operation and have shifted, using Drag&Drop, operation A10 to a date on which the resource is already loaded with another operation B10. The system must therefore shift operation B10 in the planning direction. When, by doing this, operation B10 hits a fixed operation C10, operation B10 skips over the fixed operation C10.

Retaining the current modes when rescheduling

As of Release 3.0A (FCS + SP1), you can specify in the strategy profile that the system cannot reschedule operations to alternative resources; that is, the modes for the operations are retained. When you want to use this setting for scheduling, you set the Retain current modes indicator in the strategy profile.

When you then reschedule an order, all operations retain their modes. In the DS planning board, you can still use Drag&Drop to reschedule an operation to an alternative resource; however, the dependent operations retain their modes.

Minimum distance between activities

As of Release 3.0A (FCS + SP1), the minimum distance between two activities (between which there is a relationship) is 0, when you have not entered a value for the minimum distance in the production process model or in the iPPE.

Considering the maximum distance between operations

As of Release 3.0A (FCS + SP1), you can specify in the strategy profile whether the system considers the maximum distance between the activities of various operations when scheduling and rescheduling operations.

In the case of more complex scheduling problems, it could be preferable not to consider the maximum distance so that the system can (more easily) find a solution when scheduling. This solution could then serve as a starting point for further scheduling. The system only considers the maximum distance when you have specified in the strategy profile that relationships between operations are considered.

Considering the time buffer

As of Release 3.0A (FCS + SP1), you can specify in the strategy profile that the system considers the time buffer maintained in the resources when scheduling and rescheduling operations and orders. By using the time buffer at a resource, you can control how much earlier the operations at the previous resource must be completed or how much earlier the components produced from other orders must be available at the resource. The time buffer provides a kind of safety time with which you can, to a certain extent, protect the resource from unforeseen delays in material staging.

The system can only consider the time buffer when you have specified in the strategy profile that the relationships between operations or the pegging relationships are considered.

Compact Scheduling

As of Release 3.0A (FCS + SP1), you can specify Compact scheduling in the strategy profile for scheduling and rescheduling operations. In compact scheduling, the system tries to achieve for sequences of operations or for complete orders a schedule with the smallest possible time distances between the operations; ideally, the distances are the minimum distances defined in the production process model or in the iPPE. You can use compact scheduling to keep the lead time for sequences of operations or from orders as short as possible, thereby achieving a more compact schedule. The system can only execute compact scheduling when you specified in the strategy profile that the time relationships between operations are considered. Pegging relationships are not, however, relevant for compact scheduling; the compact scheduling always refers to individual orders.

For the objects that the system should schedule compactly, the following options are available:

  • Deallocated operations
If you choose this option for compact scheduling, the system schedules the deallocated operations compactly; that is, when an operation is rescheduled that has relationships to deallocated operations, the system tries to shift the deallocated operations as close to the rescheduled operations as the minimum distance allows.
Example:
Order A contains operation A10, which is scheduled, and operation A20, which is deallocated. Between A10 and A20 there is a relationship with a defined minimum time distance. Order B contains operation B10, which is scheduled, and operation B20, which is deallocated. Between B10 and B20 there is also a relationship with a defined minimum time distance. You have specified compact scheduling for the deallocated operations.
When you reschedule the scheduled operation A10, the system tries to shift the deallocated operation A20 towards operation A10, as closely as the minimum distance (even when the relationship is not violated). When order A has a third operation A30 with a relationship to operation A20, operation A30 is shifted towards A20 (even when the relationship is not violated). However, if operation A30 is scheduled, it is not shifted (unless the relationship is violated).
In rescheduling A10, operation B10 from order B is affected, for example, because the planning mode Insert operation or Close gap is set, and B10 therefore has to be shifted. The system now tries to shift the deallocated operation B20 in such a way that the minimum distance to B10 is achieved (even when the relationship is not violated).
  • Deallocated operations and selected orders
If you choose this option for compact scheduling, the system schedules deallocated operations and the orders selected for scheduling compactly; that is:
When an operation is rescheduled, that has relationships to deallocated operations, the system tries to shift the deallocated operations as close to the rescheduled operation as the minimum distance allows.
In addition, the system also reschedules the complete orders, that you selected for scheduling, compactly. The system schedules each selected order in such a way that the smallest distance possible exists between its operations, independent of whether the operations are scheduled or deallocated.
Note:
In the DS planning board, you select an order for scheduling by marking the order or individual operations in the order. For a scheduling run, you choose an order by entering the order or the individual operations in the order. When creating an order, the order created and its component orders are the selected orders.
Example:
Order A contains operations A10, A20 and A30, which are all scheduled. Between A10 and A20 there are relationships with minimum time distances defined. Order B contains operation B10, which is scheduled, operation B20, which is deallocated, and operation B30, which is scheduled. Between B10 and B20, and B20 and B30 there are also relationships with minimum time distances defined. You have specified compact scheduling for deallocated operations and selected orders.
If you reschedule operation A10, then order A is the selected order. The system therefore executes compact planning for the whole of order A; that is, it tries to shift the scheduled operation A20 as close to operation A10 as the minimum distance allows, and the scheduled operation A30 as close to A20 as the minimum distance allows (even when the relationships were not violated).
In rescheduling A10, operation B10 from order B is affected, for example, because the planning mode Insert operation or Close gap is set, and B10 therefore has to be shifted. The system now tries to shift the deallocated operation B20 in such a way that the minimum distance to B10 is achieved (even when the relationship is not violated). The scheduled operation B30 is, however, not shifted (as long as the relationship is not violated), because you only chose order A for scheduling when rescheduling operation A10.
  • All rescheduled orders
If you choose this option for compact scheduling, the system schedules all the orders compactly that it has to reschedule when scheduling or rescheduling an operation or order, including the selected orders. The system tries to achieve the minimum distances between the operations in all of the affected orders, independent of whether the operations are scheduled or deallocated.
Example:
Order A contains operations A10, A20 and A30. Between A10 and A20, and between A20 and A30 there are relationships with minimum time distances. Order B contains operations B10, B20 and B30. Between B10 and B20, and between B20 and B30 there are also relationships with minimum time distances. You have specified compact scheduling for all rescheduled orders.
If you reschedule A10, the system executes compact scheduling for the whole of order A; that is, is tries to shift operations A20 and A30 in such a way that the minimum distances are achieved between all operations (even when the relationships were not violated).
In rescheduling A10, operation B10 from order B is affected, for example, because the planning mode Insert operation or Close gap is set, and B10 therefore has to be shifted. Due to the fact that order B is affected by rescheduling, the system executes compact scheduling for the whole of order B; that is, it also tries to shift B20 and B30 in such a way that the minimum distances are achieved (even when the relationships were not violated).

Notes:

  • When you use compact scheduling, the system only reschedules operations when the relationships to these operations were violated, and when you specified that the relationships must be considered. Rescheduling is executed in such a way that the relationships are no longer violated; that is, the distances between the operations are not less than the minimum distances, and do not exceed the maximum distances. It is therefore not necessary to set minimum distances. However, in the case of compact scheduling, rescheduling occurs even when no relationships were violated.
  • The system always tries to set the minimum distances between the activities in an operation.
  • If you do not define a minimum distance in the production process model between two operations or between two activities in an operation, the system uses the distance 0 when scheduling.

Scheduling log

In Release 3.0A (FCS + SP1):

  • The scheduling log has been newly structured
  • You can specify how many and which messages are displayed
  • The scheduling log is also integrated into the production planning run

For further information, see the release information Scheduling log.






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