Using segment sets

Segments have a specific segment length, are expressed in the segment time unit (weeks, months, four weeks, and so on), and are linked to requirement types. A segment set consists of a number of segments.

To set up a segment set, refer to Overview of purchase schedule handling.

Note

Each segment in the segment set has a unique number. The schedule horizon is built according to the sequence number that is assigned by LN in the Sequence Number field of the Segment Set - Segments (tdipu0114m000) session.
In the Schedule Segments (tdipu0115m000) session, you cannot define a segment time unit and a segment length for a segment with the Immediate requirement type, because this requirement type involves undelivered requirements from the past that must be shipped as soon as possible.

Segment sets and purchase schedules

If you use push schedules or pull forecast schedules, the segment set from the Purchase Contract Line Logistic Data (tdpur3102m000) session and/or the Items - Purchase Business Partner (tdipu0110m000) session is used to:

Regenerate schedule lines in the Regenerate Schedules (tdpur3211m000) session.
Cluster schedule lines to generate release line details with the status Created, which you can perform in the Generate Release Lines (tdpur3222m000) session.

For pull call-off schedules, no segment sets are used because these schedules lines are not regenerated, or clustered and are immediately converted to a release line detail with the status Scheduled. As a result, the requirement type is always Firm.

Note

If you link segments to the segment set in the Segment Set - Segments (tdipu0114m000) session, you must make sure that you use the correct segment time units. Make sure that:

You correctly define the first segment time unit of the first segment in a segment set. For example, if you set the first segment time unit to Week or Four Weeks, and if the calculated schedule issue date does not fall on a Monday, some days can be excluded from the clustering or regeneration process. Note that these segment time units always have Monday as a starting point for their activities. As a result, for a segment time unit defined as Week or Four Weeks, LN only starts clustering or regenerating schedule lines from a Monday on and therefore starts to cluster or regenerate schedule lines from the first Monday that follows the previously calculated schedule issue date. For a segment time unit defined as Month, LN does not start to cluster or regenerate schedule lines on the first available Monday, but on the first available Monday of the following month.
The various segments connect. For example, if you combine the weekly time unit, which runs from Monday through Sunday, with the monthly time unit, which runs from the first Monday of the month through the day before the first Monday of the following month, when you regenerate or cluster schedule lines, a period of time can be undefined.

Example

Next schedule issue date: 19/07/99

Segments in the segment set:

Segment Code	Requirement Type	Time Unit	Segment Length
1	Firm	Weeks	1
2	Planned	Months	1
3	Planned	Months	1

Segment time calculation, based on schedule issue date:

Segment Code	Start Date	End Date	Requirement Type
1	19/07/99	25/07/99	Firm
2	02/08/99	05/09/99	Planned
3	06/09/99	03/10/99	Planned

In this example, a time gap of one week exists between 26 July 1999 and 2 August 1999. Although LN automatically fills this time gap, to avoid time gaps in a segment set, use the four weeks time unit in combination with the weekly time unit.

Note

When LN regenerates schedule lines, if a period is undefined between two segments, the schedule lines that fall in this time gap automatically receive the requirement type of the segment with the highest sequence number. For example, if a time gap exists between a segment that calculates the Firm requirement type and a segment that calculates the Planned requirement type, the schedule lines that fall in this time gap automatically receive the Firm requirement type. As a result, the time gap from the previous example that runs from 26 July 1999 through 2 August 1999, automatically receives the Firm requirement type.
When LN clusters schedule lines, if a period is undefined between two segments, LN automatically adds another segment that fills this time gap so that the schedule lines that fall in this time gap are also included in the clustering process. All the schedule lines that fall within the time period of that newly generated segment, are clustered into one release line detail.
All schedule lines in a purchase release that fall after the period calculated by the last segment in a segment set, automatically receive the Planned requirement type.