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 Deactivation of Sequence-Dependent Setup Activities

Use

The goal of deactivating sequence-dependent setup activities is to keep already scheduled setup activities stable in the short-term horizon. That is to say, the setup times determined are not to change even if the order sequence is changed again (for example, due to the confirmation). You achieve this by deactivating the sequence-dependency of the setup activities for a resource. This affords the following advantages:

  • For the planner, the planning situation in the short-term horizon is more straightforward because the setup times do not change again.

  • In the partial confirmation of the setup activities, the originally determined setup time is now used to calculate the remaining duration of setup. The remaining duration is calculated using the following formula:

    Remaining duration = open quantity/original quantity x original duration

Integration

  • In the deactivation, the sequence-dependency of the activity is removed. The deactivated sequence-dependent setup activity still retains the properties of a sequence-dependent setup activity .

  • After deactivation, the original setup duration is saved as Processing Time in the Mode of the setup activity. This duration is then used for further planning and confirmation.

Prerequisites

  • The system cannot carry out an activation or deactivation of a sequence-dependent setup activity if the latter has one of the following statuses:

    • Partially confirmed

    • Finally confirmed

    • Started

  • You have made the heuristic settings in Customizing for the heuristic SAP_DS_03.

Features

Deactivation Using the Heuristic SAP_DS_03

The deactivation of the sequence-dependent setup activities at a resource can only be carried out in connection with the creation of fixing intervals using the heuristic Processing of Fixing/Planning Intervals . The fixing interval serves above all to stabilize the planning situation at the resource, because the capacity of the resource is blocked during this period and a scheduling or rescheduling of operations is thus prevented. For this reason the deactivation of sequence-dependent setup activities is only meaningful and possible in connection with fixing intervals.

Caution Caution

The deactivation of the setup activities is only possible with the heuristic. The Define Fixing Intervals function, which you can invoke from the detailed scheduling planning board menu, cannot be used for this purpose.

End of the caution.

If there is not yet a fixing interval at the resource, the system deactivates all sequence-dependent setup activities that lie within the new fixing interval when executing the heuristic. If an already existing fixing interval that was previously created by the heuristic is extended by another execution of the heuristic, the deactivated setup activities are only activated if they lie outside the new fixing interval. The sequence-dependent setup activities that lie within the new fixing interval are deactivated. Generally, all setup activities that lie within the fixing interval before or after the execution of the heuristic remain deactivated.

Deletion of Fixing Interval

The deletion of a fixing interval by the heuristic or using the maintenance transaction on the detailed scheduling planning board automatically leads to the activation of the setup activities that lie within the interval to be deleted.

Effects of Manual Changes to the Fixing Interval

If you manually change a fixing interval created by the heuristic on the detailed scheduling planning board using the transaction Define Fixing Intervals, the system performs the following actions:

  • When you manually specify in the maintenance transaction the start date/time for an already existing fixing interval created by the heuristic, the system automatically activates all sequence-dependent setup activities that lie within the fixing interval. The system must activate the setup activities because you have stipulated a start date/time for the fixing interval. This is not allowed for the deactivation of the sequence-dependent setup activities.

  • If you manually shift the end date/time of an existing fixing interval that was created by the heuristic into the future, i.e. lengthen the interval, the system does not make any changes. The setup activities that lie within the original interval remain deactivated. The setup activities located within the lengthened fixing interval remain activated.

  • If you manually bring forward the end date/time of an existing fixing interval that was created by the heuristic, i.e. shorten the interval, all sequence-dependent setup activities that lie outside the shortened interval are activated.

  • Additional fixing intervals that you create manually have no influence on fixing intervals that were created by the heuristic. If the fixing intervals overlap, the setup activities that lie within the area of overlap retain their properties, i.e. deactivated setup activities remain deactivated. The others remain activated.

Rescheduling Due to Manual Order Changes

Because the fixing interval blocks the capacity of the resource for other operations or orders during the selected period, rescheduling cannot result in changes to setup times. The only possible way of rescheduling/replanning orders (operations) that lie within the fixing interval is to change the order. However, the following actions can lead to a rescheduling even though you have created a fixing interval:

  • Change in the order quantity in the ERP system

    If you have changed the quantity in the production order in the ERP system and chose Proportional Adjustment in the process, it may happen that during rescheduling the system reschedules the deactivated sequence-dependent setup activities that lie outside the fixing interval and that, as a result, the stored setup time no longer matches up with the new predecessor activity.

    To be able to determine the deactivated setup activities that lie outside the fixing interval and reactivate them, use the heuristic SAP_DS_04 . This will enable the system to determine the correct setup time for this setup activity.

  • Change in the production version in the ERP system

  • Change in the order quantity in SAP APO

  • Change in the source of supply for an order in SAP APO

  • New BOM explosion

    If you carry out a new BOM explosion for an order in ERP or in SAP APO, the deactivated setup activities are automatically activated because the activity data is read from the master data.

  • Confirmation of orders

    Confirmed operations can also lie outside the fixing interval.If a partially confirmed operation is interrupted, first the setup activity is interrupted and then the activation takes place (if there is a deactivated setup activity) in order to avoid the creation of movable deactivated setup activities.

Activities

To be able to use the deactivation of sequence-dependent setup activities optimally, SAP recommends the following procedure:

  1. You arrange the operations at a resource in the desired sequence, e.g. using the heuristic SAP001.

  2. You execute the new heuristic SAP_DS_03 to create fixing intervals for certain resources and simultaneously deactivate the sequence-dependent setup activities.

  3. Order changes may arise in ERP or in SAP APO, due for example to quantity changes, partial confirmations, etc.

  4. You execute the additional heuristic to reactivate deactivated setup activities that lie outside the fixing interval.

  5. You delete the fixing intervals using the heuristic SAP_DS_03. In the process, the system activates the sequence-dependent setup activities.

  6. You start the process from the beginning by rearranging the operations at a resource in a certain sequence.