How Resource Scheduling Is Done

Resource scheduling can be calculated when you know the planned make order duration. The planning process uses lead times, both fixed and variable, to calculate planned make order duration. For existing work orders, the lead time is the duration of the work order.

The planning process does not change the duration of the work order. You can also manually set fixed and manual lead times.

Tip: If you manually configure the lead times, then set larger values for a conservative planning result. Set smaller values for an aggressive planning result.

For example, suppose the fixed lead time = 1

Variable lead time = 0.2.

The planned order size = 10 units

Make planned order lead time = fixed + variable multiplied by order size = 1 + 0.2 multiplied by 10 = 1 + 2 = 3 days

Demand due date = Day 5

Make planned order: Suggested start date = Day 2; Suggested due date = Day 5

The calculation assumes that day 5 ends at 23:59 and so one full day of lead time pushes the start date to day 4 at 23:59. So in the example, the 3-day lead time pushes the start date to day 2.

The following calculations are used to calculate planned make order duration, routing resource duration, operation duration, and resource duration"

• Planned make order duration: The planned make order quantity is determined by total quantity of demands and order modifiers. Total make order lead time (days) = fixed lead time + quantity multiplied with variable lead time.

• Routing resource duration: Resource requirement (in hours) is calculated for item-based resource usages. Resource requirement = Quantity multiplied by Usage hours. Operation duration (in hours) is calculated by adding each resource requirement adjusted for any simultaneous resources. Total Routing Duration = Sum of the operation duration (hours).

• The operation duration and resource duration calculations are shown in the following illustrations. Each operation and resource requirement is spread over the total make lead time.

The following figure illustrates the calculation for operation duration.

The following figure illustrates the calculation for resource duration.

For a planned make order, the planning process performs the following task:

• Calculates duration based on fixed and variable lead times.

• Calculates required resource hours from the work definition.

• Spreads the required resource hours evenly across the calculated work order duration. If the work order has multiple operations, the duration for each operation is calculated and the resource hours are spread out within the operations for assigned resources.

Rescheduling Existing Work Order

For an existing work order, you can either continue with the existing schedule or change the schedule and assign new dates. If the work order is not rescheduled, then the planning process:

• Does not change the work order start and end dates

• Does not change the operation and resource requirement start and end dates

• Spreads each resource usage evenly over the days of the resource requirement

For example, if the resource requirement start date is Day 5 and end date is Day 6, and resource usage is 14 hours, then the planning process allocates 7 hours on Day 5 and 7 hours on Day 6. If you reschedule a work order, the job duration is preserved and does not change. The lead time for each operation and for each resource requirement remain the same. Only the start and end dates change.

Planning calculations follow these guidelines while rescheduling a work order:

• Allocate the same number of days for work order start and end dates. For example, if the end date is moved by two days, then move the start date by two days.

• Allocate the same number of days to each operation and resource requirement date. Using the previous example, move each operation and resource requirement date by two days.

• Spread each resource usage evenly over the days of the resource requirement. For example, if the resource requirement start date is Day 5 and end date is Day 6, and resource usage is 14 hours, then allocate 7 hours on Day 5 and 7 hours on Day 6.

• Adjust for days on and days off by increasing or decreasing the job, operation, and resource dates. Depending on whether days off are included or removed from the work order, the relative working days remain the same before and after the move. For example, the work order duration is 5 days, starting on Friday and ending on Tuesday including two nonworking weekend days. If the work order is rescheduled to start on Monday, the new end date becomes Wednesday. If any adjusted dates for the work order are pushed into the past, then place the dates on Day 1 of the plan. If a part of the work order is completed, then only the open quantity of the work order is scheduled. If some components and resources are consumed by the work order, then only the open component requirements and open resource usages are planned in the planning process.