The Level 1 calculation considers various parameters and their settings.
If you request rolling, the estimated quantity on hand development corrects the master schedule proposals after the planning time fence. This means that the first master schedule after the planning time fence is adjusted by the estimated quantity on hand development between the run time and planning time fence. For example, if there is an excess part quantity of 100, it is subtracted from the first master schedule proposal after the planning time fence.
This indicates the maximum capacity for one work day. If this field is zero (0), capacity is unlimited. The maximum capacity per period is calculated according to the following formula:
Max capacity per period = Max capacity per day * Period length.
Level 1 calculation considers any specified lot sizes. This information is retrieved from the planning data section in the inventory part register. If the minimum and maximum lot sizes are set to zero (0), the lot size is unlimited.
Fixed master schedule proposals remain in existence until the run date, but they do not affect any calculations within the time fence demand. Variable proposals are set to zero (0) so that they can be recalculated outside the planning time fence.
Site level attributes control how master scheduling level 1 plans for a part. The selections that you make in the Manufacturing tab of the Site window determine how the system processes the part during master scheduling. Selecting the Use Released Purch Reqs in Planning check box causes master scheduling to not delete purchase requisitions in status Released at the start of the master scheduling run. These are viewed as supply later in the master scheduling process.
When demand for a part arises, shop order requisitions, production schedules, or purchase requisitions are created from the fixed master schedule proposals within the planning time fence. Multiple requisitions or schedules will be created depending on the maximum, minimum and multiple values set in the Inventory Part/Planning Data tab. However, this kind of supply is created only if the he Proposal Release field in Inventory Part/Planning Data tab is set to Release, indicating supply for the part is not managed by Kanban circuits.
If you specify that fixed master schedule proposals are to be created automatically, this happens when the variable proposals fall within the planning time fence. Quantity on hand development and quantity available to promise are based on the current quantity on hand minus safety stock.
In the presence of the Max Capacity constraint, MS will place the maximum amount possible on the original receipt date if it is outside the planning time fence. Any remaining quantity will be added to the previous existing master schedule receipt quantity until the maximum capacity is reached. This process is done repeatedly until no quantity remains or until the planning time fence is reached. After reaching the planning time fence and still have quantity remaining, new master schedule proposals are created. These proposals will be created for each work day going back from the original master schedule receipt date to the planning time fence. If planning time fence is reached and still have quantity remaining, this will be put on the date of the original requirement, even though it exceeds the Max Capacity constraint. If Max Capacity is defined so that it is less than the Min Lot Size for a given MS part, Max Capacity will be used instead of the Min Lot Size and a warning message will be generated in action messages.
The Master Schedule Receipts column in the Receipts tab shows the master schedule receipts, both Proposed and Fixed, generated by the system. The master schedule receipts, in the normal course of events, cross the planning time fence and may be set to state Fixed by the system, if indicated by the user. After this, the system generates supply proposals depending on the type of part. If it is a discrete manufactured part, then shop requisitions are generated, and the Schedule Orders column is updated to reflect this. If it is a repetitive manufactured part, then production schedules are generated, again updating the Schedule Orders column. When these supply proposals are converted into shop orders or firm production schedules, the Firm Orders column is updated to reflect this, and the Scheduled Orders column is also updated to reflect the change in status of the supply. When the shop orders are released, the Released Orders column is updated to reflect this, and the Firm Orders column is also updated to reflect the change in status of the supply. The Master Schedule Receipt column is updated only after the supply goes past due.
You can perform master scheduling for a single site, or alternatively execute master scheduling for multiple sites in support of a multi-site supply chain environment. Parts supplied from another site are defined as multi-site planned in the Supplier for Purchase Part window, indicating that the supply comes from an internal supplying site. Master scheduling generates distribution orders from fixed master schedule receipts for these material move requirements.