To compute phase numbers for master-based planning
LN bases the phase number for master planning on the following data:
- Bill of critical materials (BCM)
- Supplying relationships
LN computes phase numbers for
- Plan units (and the plan items that belong to it)
- Plan items that are not part of any plan unit
In the master-planning process, an item that is not part of any plan unit is treated as a plan unit of its own.
Criteria for phase numbers
The phase numbers of the plan units must conform to the following criteria:
- If two plan items are in different plan units, and one of these plan items is defined as a component of the other in a BCM, the phase number of the component's plan unit must be greater than the phase number of the parent's plan unit.
- If a supplying relationship exists between two plan items that belong to the same company, the phase number of the supplying item's plan unit must be greater than the phase number of the receiving item's plan unit.
- If a supplying relationship exists between two plan items that belong to different companies, and both items are controlled by central multicompany planning, the phase number of the supplying item's plan unit must be greater than the phase number of the receiving item's plan unit.
Similar criteria apply to plan items without plan units except LN uses the phase number of the plan item instead of the phase number of the plan item's plan unit.
Computation procedure
The computation of the phase numbers is an iterative process. You can choose between two methods:
- Regenerative computation
- Net-change computation
In a regenerative computation, every plan unit and every plan item without a plan unit initially gets phase number 0. LN then checks the plan units and plan items without a plan unit one by one and adjusts their phase numbers until the criteria for phase numbers are fully met. For information on the net-change computation, see Net-change phase number computation.
Example
Consider the following bill of critical materials with seven items:
Items A_1 belongs to plan unit 1, B_2 belongs to plan unit 2, and so on.
The computation yields the following result:
| Plan item | Plan unit | Phase number |
|---|---|---|
| A_1 | 1 | 0 |
| B_2 | 2 | 1 |
| C_4 | 4 | 2 |
| D_4 | 4 | 2 |
| E_4 | 4 | 2 |
| F_3 | 3 | 3 |
| G_3 | 3 | 3 |
You can see the result of the computation in the Master Phase Number field in the Plan Unit (cprpd6100m000) session for plan units and in the Master Phase Number field in the Items - Planning (cprpd1100m000) session for plan items without plan unit.