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  Calculation of the Duration of an Activity

Use

The duration of an activity is the working time that a resource needs to carry out the activity. Non-working times such as breaks or maintenance phases are not included in this duration.

The duration of a processing activity can consist of a fixed portion and a variable portion that depends on the order quantity.

As a rule, the duration of a setup activity is quantity-independent, whereas the duration of a processing activity is not.

Based on a resource utilization rate of 100%, the system calculates the duration of an activity using the following formula:

Duration of activity = fixed duration + (variable duration x order quantity/output quantity)

The data used in the calculation is described in the following table.

Data for calculating the duration of activity

Data

Description

Output quantity

Base quantity of the primary order product

You assigned the primary order product to an activity as the output product. You specify the base quantity here.

Fixed duration

Working time that is used for the activity, irrespective of the quantity produced

Variable duration

Working time taken to produce the output quantity of the primary order product (without fixed duration)

Note Note

The quantity produced by an activity may differ from the order quantity: If scrap is incurred, the activity must produce a correspondingly larger quantity. In the case of quantity-dependent resource consumption, the resource consumption of the activity also increases as a result.

End of the note.

Integration

The duration of the activity and resource consumption define the capacity requirements of the activity.

If you have defined a utilization rate other than 100% for a resource, the system must take this utilization rate into account in order scheduling. In this case, the system divides the calculated activity duration by the percentage utilization rate. In the case of processing activities, the duration must always be divided by the rate of utilization. For setup activities , you can use report /SAPAPO/TSTREAM_EFF_CHANGE to specify on a client-wide basis whether or not the utilization rate is to be taken into account. You have the following options:

  • Consider utilization rate of the resource for all setup activities

    The setup activities are treated as processing activities. To calculate the operation duration, the utilization rate is applied for both the processing activity and the setup activity.

  • Do not consider utilization rate of the resource for sequence-dependent setup activities

    In calculating the duration, the system takes the setup time from the setup matrix.

  • Do not consider utilization rate of the resource for any setup activities

    Neither sequence-dependent nor non-sequence-dependent setup activities take the utilization rate into account.

    Example Example

    The setup time the system determines from the setup matrix amounts to 60 min. The duration of processing is 5 min per piece. The order quantity is to be 100 pc. You have defined a resource utilization rate of 50%. You have specified that the rate of utilization of the resource is not to be taken into consideration for any setup activities.

    Duration of processing activity = (processing time x order quantity)/utilization rate % = (5 min x 100 pc)/50% = 1000 min

    Duration of setup activity (time from setup matrix) = 60 min

    End of the example.

Prerequisites