How to: Run MPS and MRP
The terms "running the planning worksheet" or "running MRP" refer to the calculation of the master production schedule and material requirements based on actual and forecasted demand. The planning system can calculate either Master Planning Schedule (MPS) or Material Requirements Planning (MRP) on request, or it can calculate both at the same time.
MPS is the calculation of a master production schedule based on actual demand and the production forecast. The MPS calculation is used for end items that have a forecast or a sales order line. These items are called "MPS items" and are identified dynamically when the calculation starts.
MRP is the calculation of material requirements based on actual demand for components and the production forecast on the component level. MRP is calculated only for items that are not MPS items. The purpose of MRP is to provide time-phased formal plans, by item, to supply the appropriate item, at the appropriate time, in the appropriate location, in the appropriate quantity.
The planning algorithms used for both MPS and MRP are identical. The planning algorithms pertain to netting, reuse of existing replenishment orders, and action messages. The planning system process examines what is needed or will be needed (demand) and what is on-hand or expected (supply). When these quantities are netted against each other, Microsoft Dynamics NAV provides action messages. Action messages are suggestions to create a new order, change an order (quantity or date), or cancel an order already on order. The term "order" includes purchase orders, assembly order, production orders, and transfer orders.
Proper planning results depend on the set up done on item cards, assembly BOMs, production BOMs, and routings.
Methods for Generating a Plan
Calculate Regenerative Plan: This function processes or regenerates the material plan. This process starts by deleting all planned supply orders that are currently loaded. All items in the database are replanned.
Calculate Net Change Plan: This function processes a net change plan. Items are considered in net change planning from two types of changes:
Demand/supply changes: These include modifications to quantities on sales orders, production forecasts, assembly orders, production orders, or purchase orders. An unplanned inventory level change is also considered a quantity change.
Planning parameter changes: These include changes in safety stock, reorder point, routing, bill of material, and changes to the time bucket or lead time calculation.
Get Action Messages: This function serves as a short-term planning tool by issuing action messages to alert the user of any modifications made since the last regenerative or net change plan was calculated.
With each planned method, Microsoft Dynamics NAV generates worksheet entries assuming infinite capacity. Work center and machine center capacity is not considered when you develop schedules.
The Calculate Regenerative Plan function is the most common process. The Calculate Plan and Carry out Action Messages functions, however, can be used to run the Calculate Net Change Plan process. The Get Action Messages Plan function can be run between regenerative and net change planning runs to obtain an immediate view of the effect of schedule changes, but it is not intended as a replacement of full regenerative or net change planning processes.
To calculate the planning worksheet
In the Search box, enter Planning Worksheets, and then choose the related link.
On the Home tab, in the Process group, choose Calculate Regenerative Plan to open the Calculate Plan window.
On the Options FastTab, fill in the fields as described in the following table.
Select to initiate the calculation of a master production schedule. Items with open sales orders or production forecasts are considered in this run.
Select to initiate the calculation of material requirements planning. Items with dependent requirements are considered in this run. Typically, MPS and MRP are run at the same time. To run MPS and MRP at the same time, the Combined MPS/MRP Calculation field must be selected on the Planning FastTab in the Manufacturing Setup window.
This date is used to evaluate inventory availability. If an item's on-hand quantity is below the reorder point, the system forward-schedules a replenishment order from this date. If an item is below its safety stock (as of the starting date), the system back-schedules a replenishment order due on the planning starting date.
This is the ending date of the planning horizon. Neither demand nor supply is considered after this date. If the reorder cycle for an item extends beyond the ending date, the effective planning horizon for that item is equal to the order date + reorder cycle.
The planning horizon is the time that the plan is extended to. If the horizon is too short, items with a longer lead time are not ordered on time. If the horizon is too long, too much time is spent reviewing and processing information that likely changes before it is needed. It is possible to set one planning horizon for production and a longer one for purchases, although it is not required. A planning horizon for purchases and production should be set to cover the cumulative lead time for components.
Stop and Show First Error
Select if you want the planning run to stop as soon as it encounters an error. At the same time, a message is displayed with information about the first error. If an error exists, only the successful planning lines made before the error was encountered will be presented in the planning worksheet. If you do not select this field, the Calculate Plan batch job will continue until it has completed, that is, errors will not interrupt the batch job. If one or more errors exist, a message will display after completion with information about how many items are affected. The Planning Error Log window will then open to provide more details about the error and links to the affected item cards.
Select a forecast that should be included as demand when you run the planning batch job. The default forecast is set up on the Planning FastTab in the Manufacturing Setup window.
Exclude Forecast Before
Define how much of the selected forecast to include in the planning run by entering a date before which forecast demand is not included, thus allowing you to exclude old information.
Respect Planning Parameters for Exception Warnings
By default, this field is selected.
Supply on planning lines with warnings is normally not modified according to planning parameters. Instead, the planning system only suggests a supply to cover the exact demand quantity. However, you can define certain planning parameters for planning lines to be respected with certain warnings.
For more information, see Calculate Plan - Plan. Wksh..
On the Item FastTab, set filters to run the planning based on item, item description, or location.
Choose the OK button. The batch job runs and then the planning worksheet is populated with the planning lines.
To perform action messages
In the Planning Worksheet window, on the Home tab, in the Process group, choose Carry Out Action Message.
On the Options FastTab, specify how to create the supplies. Fill in the fields as described in the following table.
Specify how you want to create production orders. You can do this directly from the planning line proposals. You can create either planned or firm planned production orders.
Specify how you want to create assembly orders. You can do this directly from the planning line proposals.
Specify how you want to create purchase orders. You can do this directly from the planning line proposals.
If you chose to copy the planning line proposals for purchase orders to the requisition worksheet, select the template and worksheet name.
Specify how you want to create transfer orders. You can do this directly from the planning line proposals.
If you chose to copy the planning line proposals for transfer orders to the requisition worksheet, select the template and worksheet name.
Combine Transfer Orders
Select if you want to combine transfer orders.
Stop and Show First Error
Select if you want the Carry Out Action Msg. - Plan. batch job to stop as soon as it encounters an error. At the same time, a message is displayed with information about the firsterror. If an error exists, only the planning lines processed before the error was encountered will create supply orders.
On the Planning Line FastTab, you can set filters to limit the perform action messages.
Choose the OK button.
The batch job deletes the lines in the planning worksheet after it has performed the action message. The other lines remain in the planning worksheet until they are either accepted at a later date or else deleted. You can also delete the lines manually.
Action messages are issued by the order tracking system when balance is unattainable in the existing order network. They can be viewed as a suggestion for you to process changes that reestablish equilibrium between supply and demand.
The generation of action messages occurs one level at a time, for each item's low-level code. This makes sure that all items that experience or will experience changes in supply or demand are considered.
To avoid small, superfluous, or unimportant action messages, the user can establish dampeners, which serve to restrict the generation of action messages to only those changes that exceed the defined quantity or number of days.
After you have reviewed the action messages and determined whether to accept some or all of the suggested changes, select the Accept Action Message field, and then you are ready to update the schedules accordingly.
An action message is a suggestion to create a new order, cancel an order, or change the quantity or date of an order. An order is a purchase order, transfer order, or production order.
In response to any supply/demand imbalances, the following action messages are generated.
If a demand cannot be fulfilled by suggesting action messages to Change Qty., Reschedule, or Reschedule & Change Qty. on existing orders, the action message New is generated, which suggests a new order. In addition, the message New is generated if there are no existing supply orders in the reorder cycle of the item in question. This parameter determines the number of periods forward and backward in the availability profile when it searches for an order to reschedule.
When demand that is tracked to a supply order experiences a quantity change, the action message Change Qty. is generated, which indicates that the related supply should be changed relative to the change in demand. If a new demand emerges, Microsoft Dynamics NAV searches for the nearest existing unreserved supply order in the reorder cycle, and issues a change of action message for that order.
When a supply or demand order experiences a date modification causing an imbalance in the order network, the action message Reschedule is generated. If there is a one-to-one relationship between demand and supply, an action message is generated suggesting that the supply order be moved accordingly. If the supply-order covers demand from more than one sales order, the supply order is re-scheduled equal to the date of the first demand.
Resch. & Chg. Qty.
If both the dates and quantities of an order have been modified, you must change plans with regard to both circumstances. Action messaging gathers both actions in one message, Resched. and Chg. Qty., to ensure that the order network returns to balance.
If a demand, which has been covered on an order-to-order basis, is deleted, an action message is generated to cancel the related supply order. If the relationship is not order-to-order, an action message is generated to change in order to reduce the supply. If through other factors, such as inventory adjustments, a supply order is not required at the time the action messages are generated by the user, Microsoft Dynamics NAV suggests an action message of Cancel in the worksheet.