| # Constraints for generating nonreferenced purchase schedule lines The following constraints can prevent Enterprise Planning to generate or update nonreferenced purchase schedule lines: Frozen zone settings Generation horizon of the patterns Expiry date of the contract Firm Planned status of the schedule line Frozen zone settings Frozen periods, which you can specify in the Purchase Contract Line Logistic Data (tdpur3102m000) session and/or the Item - Purchase Business Partner (tdipu0110m000) session, can prevent schedule lines to be generated or updated. The following frozen time zones are available: Frozen period During the frozen period, Enterprise Planning cannot generate/update schedule lines. Upper bound During the period of upper bound, the schedule line quantities can decrease, but not increase. As a result, Enterprise Planning cannot generate new schedule lines in this period. Lower bound During the period of lower bound, the schedule line quantities are allowed to increase, but not to decrease. As a result, Enterprise Planning can generate new schedule lines in this period, but existing schedule lines cannot be deleted. Note If the purchase schedule is Shipment Based, frozen time limits are based on planned shipment dates. If the schedule is Receipt Based, frozen time limits are based on planned receipt dates. If Enterprise Planning cannot increase the schedule line quantity in the frozen period or during the period of upper bound, LN automatically stores the demand at the first available delivery moment that falls outside these periods. If schedule lines are already generated for a specific item, dependent on the schedule line's freezing status, which you can view in the Frozen field of the Purchase Schedule - Lines (tdpur3111m000) session, during order simulation, Enterprise Planning first removes all schedule lines with a freezing status of Free and the Firm Planned check box cleared in the Purchase Schedule - Lines (tdpur3111m000) session. Enterprise Planning then recalculates the requirements and inserts new schedule lines. Generation horizon of the patterns In Enterprise Planning, requirements are grouped based on the delivery moments generated in the Generate Planned Delivery Moments (tdipu0225m000) session. In the Generate Planned Delivery Moments (tdipu0225m000) session, you must define a horizon end date. The horizon end date is the date until which the delivery moments are stored in the Planned Delivery Moments (Receipt Based) (tdipu0126m000) session and the Planned Delivery Moments (Shipment Based) (tdipu0125m000) session, from which they can be called on by Enterprise Planning for lead time offsetting. Because delivery moments are not calculated for the period after the horizon end date, Enterprise Planning cannot find valid delivery moment for this period. As a result, for the period after the horizon end date, Enterprise Planning is free to plan its own delivery moments. Expiry date of the contract If requirements fall after the contract's expiry date, valid business partners can no longer be found. As a result, Enterprise Planning generates planned purchase orders without a supplier. In this case, LN sends a signal to Enterprise Planning that a planned purchase order is generated instead of a schedule line. Firm Planned status of the schedule line If you click Firm Planned in the Purchase Schedule - Lines (tdpur3111m000) session, a schedule line is made Firm Planned. As a result, the schedule line cannot be changed during the next run of Enterprise Planning. Example
P1 | The frozen period.
P2 | The period of lower bound. If the frozen zone- ended before the frozen zone+, an upper bound would be applicable.
P3 | For this period, the delivery moments generated in the Generate Planned Delivery Moments (tdipu0225m000) session, which are displayed in the Planned Delivery Moments (Shipment Based) (tdipu0125m000) or the Planned Delivery Moments (Receipt Based) (tdipu0126m000) sessions, can be used by Enterprise Planning for lead time offsetting, and schedule lines can be generated.
P4 | The period for which no valid delivery moments are available in the Planned Delivery Moments (Shipment Based) (tdipu0125m000) or the Planned Delivery Moments (Receipt Based) (tdipu0126m000) sessions. In this period, Enterprise Planning is free to plan its own delivery moments when generating schedule lines.
P5 | The contract has expired. A planned purchase order is generated instead of a purchase schedule line.
Related topics Overview of purchase schedule handling Using planned delivery moments |