Managing Customer Schedules

Several functions influence the outcome of customer schedules. The following paragraphs describe the functions, including the way they interact with each other when determining schedule outcome.

A required ship schedule (RSS) identifies, for a particular customer and scheduled order, the item quantities you need to ship and the days on which you need to ship them. When you create an RSS, the system considers the customer’s shipping schedule and planning schedule along with other factors to calculate ship days and required quantities.

Because shipping schedules typically dictate shorter ship days than the planning schedule, the system contains logic that lets you specify how the system holds or nets the planning quantities against the shipping quantities. The Netting Logic field in the Order Line the system resolves shipping and planning schedule requirements when it creates the RSS.

Netting logic determines how the system builds RSSs and the demand input to the Materials Requirements Plan (MRP).

Requirements-based users typically use netting logic option 3. Option 3 replaces the beginning of the planning schedule with the shipping schedule in each week that both planning and shipping schedules exist. Cumulative-based users typically use netting logic option 4. With option 4, the shipping schedule consumes the planning schedule in each week that both planning and shipping schedules exist.

Shipping schedule problems can arise during the last week when the shipping schedule and the planning schedule overlap; however, netting logic option 5 resolves the overlap issue. Netting logic 5 does not consider excess planning quantities in any other week other than the last overlap week. Netting logic 5 calculates the excess planning quantity in the last overlap week, compares the shop calendar to the customer calendar to determine which calendar has the shortest work week, then spreads the excess planning quantity over the remaining open work days according to the calendar with the shortest work week. This results in a more level schedule.

Example: Netting Logic Example provides an example of netting logic. The table depicts a four-week period. The customer sent a shipping schedule release that covers week 1 and 2. The planning schedule release covers all four weeks. The last five rows show the quantities required based on the five netting logic choices.


	Week 1			Week 2					Week 3	Week 4
Shipping Schedule	10	10	10	5	5	5
Planning Schedule	50			40					50	40
Netting Logic 1	10	10	10	5	5	5
Netting Logic 2	50			40					50	40
Netting Logic 3	10	10	10	5	5	5			50	40
Netting Logic 4	10	10	30	5	5	30			50	40
Netting Logic 5	10	10	10	5	5	5	12	13	50	40

As shown in the table, if you specify netting logic 3, the shipping schedule takes precedence in week 1 and 2 because it overlaps the planning schedule for this period. In week 3 and 4, there is no shipping schedule requirement, so the planning schedule dictates the quantities.

If you specify netting logic 4, the shipping schedule is in place up until the last day that it is in effect. The amount on the last day is adjusted, though, to meet the consumed planning schedule.

If you specify netting logic 5, the system determines the available operating days on which to spread the excess planning quantities by selecting either the shop or customer calendar. In the example, the system used a shop calendar that is open Monday to Friday because it has the shortest work week. Week 2 is the last overlap.

See Determining Open Days for Netting Logic.

When you specify option 5 for the Netting Logic field, the system must determine the first available open work day. An open work day is a valid business day on the selected calendar on which there are no identified shipping requirements.

The system selects the days on which to place excess planning requirements based on open work days in either the customer calendar or the shop calendar.

The system determines which calendar to add excess planning quantities by calculating the gap in days between the last shipping requirement and the first open day in both calendars. The system selects the calendar with the smallest gap since this provides the most efficient RSS. If the gap in days is equal in both calendars, the system selects the calendar that has the shortest working week.

Example: The shipping schedule shows 30 quantities for the week: 10 quantities for Monday, 10 quantities for Tuesday, and 10 quantities for Wednesday. The planning schedule shows 60 quantities for the same week. This results in an excess planning quantity of 30 in the overlap week.

The shop calendar shows open days as Monday through Friday. The customer calendar shows open days as Monday through Saturday.

When you specify netting logic 5, the system compares the shop calendar to the customer calendar. Because the shop calendar has the shortest gap, the system uses it to determine open days. It then spreads the excess planning quantity of 30 over the two remaining open work days of the shop calendar. So, the last overlap week on the RSS is as follows:

If the customer calendar work days were from Monday through Thursday, the system would use the customer calendar to spread the excess planning quantity. In this case, the RSS would show the following results for the last overlap week: