Master-based CTP check
For the master-based CTP check, standard items and generic items do not differ from each other. The master-based components CTP check is performed between the order horizon and the planning horizon of the end item. The bill of critical materials is used to find components that are critical in CTP.
LN takes the quantity required and the lead-time offset defined in the bill of critical materials (BCM) line into account when adding the component ATP to the end item’s ATP.
The component CTP quantity is derived from the item master plan, so it is checked based on the plan period buckets as defined in the Scenario - Periods (cprpd4120m000) session. As a result, the cumulative component CTP of every subsequent plan period is taken during the check.
Component CTP increases the ATP with the quantity you can produce on date t, based on component ATP:
Example
Consider the acceptance of a sales order for item A on date t.
Item A has a critical material B and C. A production order takes three days and requires C at the start. Material B is required one day later, so the BCM has a two-day offset for material B, and three days for C.
The sales order is for 10 pieces, ATP of item A on date t is five. Because this amount is insufficient, component CTP is checked. ATP for C on t-3 is 12, and ATP for B on t-2 is 15. Therefore, you can produce 12 more. As a result, CTP is 5 + 12 = 17, and the order can be accepted.
The master-based capacity CTP is checking the work center availability between the order horizon and the planning horizon. The bill of critical capacities is used to find capacities that are critical in CTP.
The capacity CTP value is derived from the resource master plan, therefore, the capacity is checked based on the plan period buckets as defined in the Scenario - Periods (cprpd4120m000) session. As a result, LN takes the cumulative capacity CTP of every subsequent plan period during the check.
The cumulative capacity CTP for a resource appears in the Resource Master Plan (cprmp3501m000) session and is expressed in hours. Using the Lead-Time Offset, and Capacity Required fields in the Bill of Critical Capacities (cprpd3130m000) session, this capacity is translated into an additional cumulative ATP quantity for the finished good that can be promised.
Example
If the Cumulative Capacity CTP is four hours and the Capacity Required is 0.5 hours, the cumulative ATP quantity of the finished good increases by eight pieces. For the correct timing of these quantities, the lead-time offset is taken into account. This calculation is performed as follows:
Using the same sales order example, with critical work center WC.
The bill of critical capacities (BCC) has three-day offset for WC, and one piece requires 0.5 hour capacity.
Free capacity for WC on t-3 is four hours, thus eight pieces. Therefore, CTP is 5+8.